Merge branch 'v0.8.0' into ifcmax/initial-refresh

Example error: `error: ‘uint64_t’ has not been declared uint64_t blob_file_number, uint64_t total_blob_count,`

See https://github.com/facebook/rocksdb/issues/13365

.github/workflows/ci-bonsai-daily.yml

@@ -109,7 +109,7 @@ jobs:
           # Ensure Bonsai and ifcsverchok enable/disable works before uploading to extensions repo.
 
           # Download Blender.
-          wget -q -O blender.tar.xz https://download.blender.org/release/Blender5.1/blender-5.1.0-linux-x64.tar.xz
+          wget -q -O blender.tar.xz https://download.blender.org/release/Blender5.2/blender-5.2.0-linux-x64.tar.xz
           tar -xf blender.tar.xz
 
           # Setup Blender.
@@ -179,8 +179,7 @@ jobs:
           blender --online-mode --command extension install --enable --sync sun_position
 
           cd IfcOpenShell/src/bonsai
-          pip install pytest-blender
-          pip install pytest-bdd
+          pip install -r requirements-dev.txt
           blender --background --python scripts/setup_pytest.py
           blender --python-expr "import bonsai; print(bonsai.bbim_semver); import ifcopenshell; print(ifcopenshell.version)" --background
           make test

.github/workflows/ci-ifcwrap-standalone.yml

@@ -0,0 +1,155 @@
+# This file was generated with the assistance of an AI coding tool.
+name: ci-ifcwrap-standalone
+
+on:
+  workflow_dispatch:
+  pull_request:
+    paths:
+      - ".github/workflows/ci-ifcwrap-standalone.yml"
+      - "cmake/**"
+      - "src/ifcwrap/**"
+      - "src/ifcparse/**"
+      - "src/ifcgeom/**"
+      - "src/serializers/**"
+      - "src/ifcconvert/**"
+      - "src/ifcopenshell-python/**"
+      - "src/svgfill/**"
+  push:
+    paths:
+      - ".github/workflows/ci-ifcwrap-standalone.yml"
+      - "cmake/**"
+      - "src/ifcwrap/**"
+      - "src/ifcparse/**"
+      - "src/ifcgeom/**"
+      - "src/serializers/**"
+      - "src/ifcconvert/**"
+      - "src/ifcopenshell-python/**"
+      - "src/svgfill/**"
+
+env:
+  IFCOPENSHELL_PREFIX: ${{ github.workspace }}/ifcopenshell-install
+
+jobs:
+  build-ifcopenshell:
+    runs-on: ubuntu-22.04
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Install C++ dependencies
+        run: |
+          sudo apt update
+          sudo apt-get install --no-install-recommends -y \
+            cmake \
+            gcc \
+            g++ \
+            libboost-date-time-dev \
+            libboost-filesystem-dev \
+            libboost-iostreams-dev \
+            libboost-program-options-dev \
+            libboost-regex-dev \
+            libboost-system-dev \
+            libboost-thread-dev \
+            libeigen3-dev \
+            libocct-data-exchange-dev \
+            libocct-draw-dev \
+            libocct-foundation-dev \
+            libocct-modeling-algorithms-dev \
+            libocct-modeling-data-dev \
+            libocct-ocaf-dev \
+            libocct-visualization-dev \
+            libpcre3-dev \
+            libtbb-dev \
+            libxml2-dev \
+            libxi-dev \
+            occt-misc \
+            tcl-dev \
+            tk-dev \
+            swig
+
+      - name: Configure minimal IfcOpenShell
+        run: |
+          cmake -S cmake -B build-ifcopenshell \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_INSTALL_PREFIX="${IFCOPENSHELL_PREFIX}" \
+            -DCMAKE_PREFIX_PATH=/usr \
+            -DCMAKE_SYSTEM_PREFIX_PATH=/usr \
+            -DMINIMAL_BUILD=ON \
+            -DBUILD_IFCPYTHON=OFF \
+            "-DSCHEMA_VERSIONS=4x3_add2"
+
+      - name: Build and install minimal IfcOpenShell
+        run: |
+          cmake --build build-ifcopenshell --target install -j "$(nproc)"
+
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v6
+        with:
+          python-version: 3.11
+
+      - name: Install Python import dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install numpy typing_extensions
+
+      - name: Configure standalone IfcPython
+        run: |
+          PYTHON_EXECUTABLE="$(python -c 'import sys; print(sys.executable)')"
+          PYTHON_INCLUDE_DIR="$(python -c 'import sysconfig; print(sysconfig.get_path("include"))')"
+
+          cmake -S src/ifcwrap -B "build-ifcwrap-311" \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_PREFIX_PATH="${IFCOPENSHELL_PREFIX};/usr" \
+            -DPython_EXECUTABLE:FILEPATH="${PYTHON_EXECUTABLE}" \
+            -DPython_INCLUDE_DIR:PATH="${PYTHON_INCLUDE_DIR}" \
+            -DPYTHON_EXECUTABLE:FILEPATH="${PYTHON_EXECUTABLE}" \
+            -DPYTHON_INCLUDE_DIR:PATH="${PYTHON_INCLUDE_DIR}"
+
+      - name: Build and install standalone IfcPython
+        run: |
+          cmake --build "build-ifcwrap-311" --target install -j "$(nproc)"
+
+      - name: Import installed IfcPython
+        run: |
+          PYTHONPATH="${RUNNER_TEMP}/ifcopenshell-python" python - <<'PY'
+          import ifcopenshell
+
+          print("IfcOpenShell import ok:", ifcopenshell.version)
+          PY
+
+      - name: Set up Python 3.12
+        uses: actions/setup-python@v6
+        with:
+          python-version: 3.12
+
+      - name: Install Python import dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install numpy typing_extensions
+
+      - name: Configure standalone IfcPython
+        run: |
+          PYTHON_EXECUTABLE="$(python -c 'import sys; print(sys.executable)')"
+          PYTHON_INCLUDE_DIR="$(python -c 'import sysconfig; print(sysconfig.get_path("include"))')"
+
+          cmake -S src/ifcwrap -B "build-ifcwrap-312" \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_PREFIX_PATH="${IFCOPENSHELL_PREFIX};/usr" \
+            -DPython_EXECUTABLE:FILEPATH="${PYTHON_EXECUTABLE}" \
+            -DPython_INCLUDE_DIR:PATH="${PYTHON_INCLUDE_DIR}" \
+            -DPYTHON_EXECUTABLE:FILEPATH="${PYTHON_EXECUTABLE}" \
+            -DPYTHON_INCLUDE_DIR:PATH="${PYTHON_INCLUDE_DIR}"
+
+      - name: Build and install standalone IfcPython
+        run: |
+          cmake --build "build-ifcwrap-312" --target install -j "$(nproc)"
+
+      - name: Import installed IfcPython
+        run: |
+          PYTHONPATH="${RUNNER_TEMP}/ifcopenshell-python" python - <<'PY'
+          import ifcopenshell
+
+          print("IfcOpenShell import ok:", ifcopenshell.version)
+          PY

.github/workflows/ci-lint.yaml

@@ -27,10 +27,7 @@ jobs:
       - name: Install dependencies
         run: |
           curl -LsSf https://astral.sh/uv/install.sh | sh
-          uv tool install ruff
-          uv tool install black
-          uv tool install poethepoet
-          uv tool install ty==0.0.34
+          cat requirements-tools.txt | xargs -L1 uv tool install
 
       # black doesn't catch all syntax errors, so we check them explicitly.
       - name: Check syntax errors

.github/workflows/ci.yml

@@ -10,9 +10,13 @@ on:
       - 'src/ifcgeomserver/**'
       - 'src/ifcjni/**'
       - 'src/ifcmax/**'
+      - 'src/ifc5d/**'
+      - 'src/ifcedit/**'
+      - 'src/ifcmcp/**'
       - 'src/ifcopenshell-python/**'
       - '!src/ifcopenshell-python/docs/**'
       - 'src/ifcparse/**'
+      - 'src/ifcquery/**'
       - 'src/ifcwrap/**'
       - 'src/qtviewer/**'
       - 'src/svgfill/**'
@@ -51,7 +55,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install xmlschema xsdata numpy lxml pytest isodate lark networkx tabulate python-dateutil shapely pyparsing
+          pip install xmlschema xsdata numpy lxml pytest isodate lark networkx tabulate python-dateutil shapely pyparsing psutil
           pip install src/bcf --no-deps
           pip install pytest-xdist==3.8.0
 
@@ -252,13 +256,26 @@ jobs:
           pip install deepdiff
           cd ../ifcdiff && make test || ERROR=1
           cd ../ifcpatch && make test || ERROR=1
+          pip install -e ../ifc5d --no-deps
+          pip install odfpy xlsxwriter
+          cd ../ifc5d && make test || ERROR=1
+          pip install -e ../ifcquery --no-deps
+          cd ../ifcquery && make test || ERROR=1
+          pip install -e ../ifcedit --no-deps
+          cd ../ifcedit && make test || ERROR=1
+          pip install mcp
+          pip install -e ../ifcmcp --no-deps
+          cd ../ifcmcp && make test || ERROR=1
           pip install -e ../ifctester --no-deps
           cd ../ifctester && make test || ERROR=1
           make build-ids-docs || ERROR=1
           # Run mathutils related tests at the end to ensure no other code is relying on mathutils.
+          # mathutils only has pre-built wheels for Python 3.13+; skip on older versions.
           cd ../ifcopenshell-python
-          pip install mathutils
-          make test-mathutils || ERROR=1
+          if python -c "import sys; sys.exit(0 if sys.version_info >= (3, 13) else 1)"; then
+            pip install mathutils
+            make test-mathutils || ERROR=1
+          fi
           if [ $ERROR -ne 0 ]; then
             echo "One or more tests failed";
             exit 1;

.gitignore

@@ -4,6 +4,8 @@
 /_deps-vs*-x*-installed/
 /_installed-vs*-x*/
 /build/
+/build.log
+/output/
 /src/examples/build/
 # ifctester docs output
 /src/ifctester/test/build/
@@ -22,12 +24,14 @@
 __pycache__
 *.py.bak
 venv
+uv.lock
 
 # Visual Studio Code files
 .vscode
 !.vscode/launch.json
 !.vscode/tasks.json
 .vs
+/*.code-workspace
 
 # PyCharm files
 .idea
@@ -126,5 +130,7 @@ src/ifcopenshell-python/ifcopenshell/express/*.exp.cache.dat
 
 # temp files from AI coding tools
 *.claude
+CLAUDE.local.md
 *.py.tmp*
 *.json.tmp*
+

cmake/CMakeLists.txt

@@ -27,13 +27,14 @@ endif()
 set(CMAKE_CXX_STANDARD_REQUIRED ON) # not necessary, but encouraged
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-if(VERSION_OVERRIDE)
-    file(READ "../VERSION" "RELEASE_VERSION_")
-    string(STRIP "${RELEASE_VERSION_}" RELEASE_VERSION)
-    message(STATUS "Detected version '${RELEASE_VERSION}'")
-else()
-    set(RELEASE_VERSION "0.8.0")
-endif()
+# The VERSION file in the repository root is the single source of truth for the
+# release version. Read it unconditionally so a plain source build reports the
+# real version through buildinfo.cpp instead of the stale hardcoded 0.8.0
+# fallback (see #8164). VERSION_OVERRIDE still controls the branch name used
+# when ADD_COMMIT_SHA embeds a commit sha.
+file(READ "../VERSION" "RELEASE_VERSION_")
+string(STRIP "${RELEASE_VERSION_}" RELEASE_VERSION)
+message(STATUS "Detected version '${RELEASE_VERSION}'")
 
 add_definitions(-D_DISABLE_CONSTEXPR_MUTEX_CONSTRUCTOR)
 
@@ -313,8 +314,12 @@ if(WASM_BUILD)
 else()
     # @todo review this, shouldn't this be all possible header-only now?
     # ... or rewritten using C++17 features?
+    # Boost.System has been header-only since 1.69 and its compiled stub library
+    # was dropped in newer Boost, so requesting it as a component makes
+    # find_package fail on Boost 1.70 and up (for example Boost 1.90). It is
+    # still pulled in transitively by thread / iostreams where needed, so do not
+    # request it explicitly.
     set(BOOST_COMPONENTS
-        system
         program_options
         regex
         thread
@@ -558,8 +563,8 @@ if(COMPILE_SCHEMA)
     # Bootstrap the parser
     message(STATUS "Compiling schema, this will take a while...")
     execute_process(
-        COMMAND ${PYTHON_EXECUTABLE} bootstrap.py express.bnf
-        WORKING_DIRECTORY ../src/ifcexpressparser
+        COMMAND ${PYTHON_EXECUTABLE} bootstrap.py
+        WORKING_DIRECTORY ../src/ifcopenshell-python/ifcopenshell/express
         OUTPUT_FILE express_parser.py
         RESULT_VARIABLE SUCCESS
     )
@@ -570,7 +575,7 @@ if(COMPILE_SCHEMA)
 
     # Generate code
     execute_process(
-        COMMAND ${PYTHON_EXECUTABLE} ../ifcexpressparser/express_parser.py ../../${COMPILE_SCHEMA}
+        COMMAND ${PYTHON_EXECUTABLE} ../ifcopenshell-python/ifcopenshell/express/express_parser.py ../../${COMPILE_SCHEMA}
         WORKING_DIRECTORY ../src/ifcparse
         OUTPUT_VARIABLE COMPILED_SCHEMA_NAME
     )
@@ -660,6 +665,11 @@ if(ADD_COMMIT_SHA)
     endif()
 endif(ADD_COMMIT_SHA)
 
+# Always expose the release version (from the VERSION file) to buildinfo.cpp so
+# that a build without commit-sha info reports the correct version instead of a
+# stale hardcoded fallback. See #8164.
+target_compile_definitions(IfcParse PRIVATE IFCOPENSHELL_VERSION_STRING=${RELEASE_VERSION})
+
 if(MSVC)
     # @todo still needs to be understood better, but the cgal and cgal-simple kernel cause multiply defined boost lambda placeholders _1 ... _3
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /FORCE:MULTIPLE")

cmake/FindIfcOpenShell.cmake

@@ -0,0 +1,131 @@
+# This file was generated with the assistance of an AI coding tool.
+################################################################################
+#                                                                              #
+# This file is part of IfcOpenShell.                                           #
+#                                                                              #
+# IfcOpenShell is free software: you can redistribute it and/or modify         #
+# it under the terms of the Lesser GNU General Public License as published by  #
+# the Free Software Foundation, either version 3.0 of the License, or          #
+# (at your option) any later version.                                          #
+#                                                                              #
+# IfcOpenShell is distributed in the hope that it will be useful,              #
+# but WITHOUT ANY WARRANTY; without even the implied warranty of               #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 #
+# Lesser GNU General Public License for more details.                          #
+#                                                                              #
+# You should have received a copy of the Lesser GNU General Public License     #
+# along with this program. If not, see <http://www.gnu.org/licenses/>.         #
+#                                                                              #
+################################################################################
+
+include("${CMAKE_CURRENT_LIST_DIR}/utilities.cmake" OPTIONAL)
+
+set(_IfcOpenShell_find_args)
+if(IfcOpenShell_FIND_VERSION)
+    list(APPEND _IfcOpenShell_find_args "${IfcOpenShell_FIND_VERSION}")
+    if(IfcOpenShell_FIND_VERSION_EXACT)
+        list(APPEND _IfcOpenShell_find_args EXACT)
+    endif()
+endif()
+list(APPEND _IfcOpenShell_find_args CONFIG QUIET)
+if(IfcOpenShell_FIND_COMPONENTS)
+    list(APPEND _IfcOpenShell_find_args COMPONENTS ${IfcOpenShell_FIND_COMPONENTS})
+endif()
+
+set(_IfcOpenShell_saved_module_path "${CMAKE_MODULE_PATH}")
+list(REMOVE_ITEM CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}")
+find_package(IfcOpenShell ${_IfcOpenShell_find_args})
+set(CMAKE_MODULE_PATH "${_IfcOpenShell_saved_module_path}")
+
+if(NOT IfcOpenShell_FOUND)
+    set(_IfcOpenShell_error "Could not find an IfcOpenShell CMake config package. Set IfcOpenShell_DIR or CMAKE_PREFIX_PATH.")
+    if(IfcOpenShell_FIND_REQUIRED)
+        message(FATAL_ERROR "${_IfcOpenShell_error}")
+    elseif(NOT IfcOpenShell_FIND_QUIETLY)
+        message(STATUS "${_IfcOpenShell_error}")
+    endif()
+    return()
+endif()
+
+set(_IfcOpenShell_required_targets IfcOpenShell::IfcParse IfcOpenShell::IfcGeom)
+set(_IfcOpenShell_missing_targets "")
+foreach(_IfcOpenShell_target IN LISTS _IfcOpenShell_required_targets)
+    if(NOT TARGET ${_IfcOpenShell_target})
+        list(APPEND _IfcOpenShell_missing_targets ${_IfcOpenShell_target})
+    endif()
+endforeach()
+
+if(_IfcOpenShell_missing_targets)
+    set(IfcOpenShell_FOUND FALSE)
+    string(REPLACE ";" ", " _IfcOpenShell_missing_targets_text "${_IfcOpenShell_missing_targets}")
+    set(_IfcOpenShell_error "IfcOpenShell config was found, but required targets are missing: ${_IfcOpenShell_missing_targets_text}.")
+    if(IfcOpenShell_FIND_REQUIRED)
+        message(FATAL_ERROR "${_IfcOpenShell_error}")
+    elseif(NOT IfcOpenShell_FIND_QUIETLY)
+        message(STATUS "${_IfcOpenShell_error}")
+    endif()
+    return()
+endif()
+
+if(NOT DEFINED IFCOPENSHELL_WITH_OPENCASCADE)
+    set(IFCOPENSHELL_WITH_OPENCASCADE OFF)
+    if(TARGET IfcOpenShell::geometry_kernel_opencascade)
+        set(IFCOPENSHELL_WITH_OPENCASCADE ON)
+    endif()
+endif()
+
+if(NOT DEFINED IFCOPENSHELL_WITH_CGAL)
+    set(IFCOPENSHELL_WITH_CGAL OFF)
+    if(TARGET IfcOpenShell::IFCOPENSHELL_CGAL)
+        set(IFCOPENSHELL_WITH_CGAL ON)
+    endif()
+endif()
+
+if(NOT DEFINED IFCOPENSHELL_IFCXML)
+    set(IFCOPENSHELL_IFCXML OFF)
+endif()
+
+if(NOT DEFINED IFCOPENSHELL_WITH_ROCKSDB)
+    set(IFCOPENSHELL_WITH_ROCKSDB OFF)
+endif()
+
+set(IFCOPENSHELL_LIBRARIES IfcOpenShell::IfcParse)
+foreach(_IfcOpenShell_target IN ITEMS IfcOpenShell::geometry_serializer IfcOpenShell::Serializers)
+    if(TARGET ${_IfcOpenShell_target})
+        list(APPEND IFCOPENSHELL_LIBRARIES ${_IfcOpenShell_target})
+    endif()
+endforeach()
+
+set(IFCOPENSHELL_KERNEL_LIBRARIES "")
+foreach(_IfcOpenShell_target IN ITEMS
+    IfcOpenShell::geometry_kernel_opencascade
+    IfcOpenShell::geometry_kernel_cgal
+    IfcOpenShell::geometry_kernel_cgal_simple
+)
+    if(TARGET ${_IfcOpenShell_target})
+        list(APPEND IFCOPENSHELL_KERNEL_LIBRARIES ${_IfcOpenShell_target})
+    endif()
+endforeach()
+
+set(IFCOPENSHELL_GEOMETRY_LIBRARIES IfcOpenShell::IfcGeom ${IFCOPENSHELL_KERNEL_LIBRARIES})
+
+if(TARGET IfcOpenShell::OpenCASCADE_INTERFACE)
+    set(OpenCASCADE_LIBRARIES IfcOpenShell::OpenCASCADE_INTERFACE)
+endif()
+
+if(TARGET IfcOpenShell::IFCOPENSHELL_CGAL)
+    set(CGAL_LIBRARIES IfcOpenShell::IFCOPENSHELL_CGAL)
+endif()
+
+if(TARGET IfcOpenShell::svgfill)
+    set(IFCOPENSHELL_SVGFILL_LIBRARY IfcOpenShell::svgfill)
+endif()
+
+mark_as_advanced(IfcOpenShell_DIR)
+
+unset(_IfcOpenShell_error)
+unset(_IfcOpenShell_find_args)
+unset(_IfcOpenShell_missing_targets)
+unset(_IfcOpenShell_missing_targets_text)
+unset(_IfcOpenShell_required_targets)
+unset(_IfcOpenShell_target)

cmake/IfcOpenShellConfig.cmake.in

@@ -7,12 +7,26 @@ set(IFCOPENSHELL_WITH_OPENCASCADE @WITH_OPENCASCADE@)
 set(IFCOPENSHELL_WITH_CGAL @WITH_CGAL@)
 set(IFCOPENSHELL_IFCXML @IFCXML_SUPPORT@)
 set(IFCOPENSHELL_WITH_ROCKSDB @WITH_ROCKSDB@)
+set(IFCOPENSHELL_COLLADA_SUPPORT @COLLADA_SUPPORT@)
+set(IFCOPENSHELL_GLTF_SUPPORT @GLTF_SUPPORT@)
+set(IFCOPENSHELL_HDF5_SUPPORT @HDF5_SUPPORT@)
+set(IFCOPENSHELL_WITH_PROJ @WITH_PROJ@)
+set(IFCOPENSHELL_USD_SUPPORT @USD_SUPPORT@)
 
 include(CMakeFindDependencyMacro)
 
-set(Boost_USE_STATIC_LIBS ON)
-set(Boost_USE_STATIC_RUNTIME OFF)
-set(Boost_USE_MULTITHREADED ON)
+set(IFCOPENSHELL_BOOST_USE_STATIC_LIBS "@Boost_USE_STATIC_LIBS@")
+set(IFCOPENSHELL_BOOST_USE_STATIC_RUNTIME "@Boost_USE_STATIC_RUNTIME@")
+set(IFCOPENSHELL_BOOST_USE_MULTITHREADED "@Boost_USE_MULTITHREADED@")
+if(NOT "${IFCOPENSHELL_BOOST_USE_STATIC_LIBS}" STREQUAL "")
+    set(Boost_USE_STATIC_LIBS ${IFCOPENSHELL_BOOST_USE_STATIC_LIBS})
+endif()
+if(NOT "${IFCOPENSHELL_BOOST_USE_STATIC_RUNTIME}" STREQUAL "")
+    set(Boost_USE_STATIC_RUNTIME ${IFCOPENSHELL_BOOST_USE_STATIC_RUNTIME})
+endif()
+if(NOT "${IFCOPENSHELL_BOOST_USE_MULTITHREADED}" STREQUAL "")
+    set(Boost_USE_MULTITHREADED ${IFCOPENSHELL_BOOST_USE_MULTITHREADED})
+endif()
 set(Boost_COMPONENTS
     system
     program_options
@@ -43,13 +57,33 @@ if(IFCOPENSHELL_WITH_ROCKSDB)
 endif()
 
 if(IFCOPENSHELL_IFCXML)
-    find_dependency(LibXml2 CONFIG)
+    find_dependency(LibXml2)
 endif()
 
 if(IFCOPENSHELL_WITH_CGAL)
     find_dependency(CGAL CONFIG)
 endif()
 
+if(IFCOPENSHELL_COLLADA_SUPPORT)
+    find_dependency(OpenCOLLADA)
+endif()
+
+if(IFCOPENSHELL_GLTF_SUPPORT)
+    find_dependency(nlohmann_json CONFIG)
+endif()
+
+if(IFCOPENSHELL_HDF5_SUPPORT)
+    find_dependency(HDF5 COMPONENTS C CXX)
+endif()
+
+if(IFCOPENSHELL_WITH_PROJ)
+    find_dependency(PROJ)
+endif()
+
+if(IFCOPENSHELL_USD_SUPPORT)
+    find_dependency(USD)
+endif()
+
 if(IFCOPENSHELL_WITH_OPENCASCADE)
     find_dependency(OpenCASCADE CONFIG)
     if(OpenCASCADE_VERSION VERSION_LESS "7.7.0")

docker/.dockerignore

@@ -0,0 +1,3 @@
+.env
+*.pyc
+__pycache__

docker/.gitignore

@@ -0,0 +1,3 @@
+.env
+*.pyc
+__pycache__

docker/.ifcos_env

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# .ifcos_env
+# register autocompletes. just source the file in your shell, i.e. 
+# source .ifcos_env
+
+.ifcos_env() {
+    local cur prev opts
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    opts="create update up down restart build attach logs ps config remove help"
+
+    # Basic static completion
+    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+
+    return 0
+}
+
+# Register the completion for the command "ifcos_env"
+complete -F .ifcos_env ./ifcos_env

docker/Dockerfile

@@ -0,0 +1,67 @@
+FROM rockylinux:9
+
+# Update system, enable CRB (needed by some EPEL packages) and install EPEL,
+# then install required packages + some common tools for a bit of command
+# line comfort. Combined into one layer so a later `create` always installs
+# against packages from the same dnf update, rather than layering fresh
+# installs on top of a stale cached "update" layer.
+RUN dnf update -y && \
+    dnf install -y epel-release && \
+    dnf config-manager --set-enabled crb && \
+    dnf install -y --allowerasing --setopt=install_weak_deps=False --setopt=tsflags=nodocs \
+                   bash-completion vim git curl wget which tree htop sudo   \
+                   gcc gcc-c++ autoconf automake bison make zip cmake      \
+                   python3 python3-pip                                    \
+                   bzip2 patch mesa-libGL-devel libffi-devel fontconfig-devel \
+                   sqlite-devel bzip2-devel zlib-devel openssl-devel xz-devel \
+                   readline-devel ncurses-devel libuuid-devel git-lfs      \
+                   findutils xz byacc ccache && \
+    git lfs install --system && \
+    dnf clean all && \
+    rm -rf /var/cache/dnf
+
+# Trust bind-mounted repos regardless of which user (root or builder) or host
+# UID owns them, rather than a per-user config that only one of them sees.
+RUN git config --system --add safe.directory '*'
+
+# Configure ccache. CCACHE_MAXSIZE (not `ccache -M`) because /ccache is a
+# volume mount point at runtime - anything `ccache -M` writes to a config
+# file under it during this build gets shadowed once the real volume is
+# mounted, so the size cap only actually takes effect via the env var.
+# 2G is generous: a full build (IfcParse+IfcGeom+IfcConvert+wrapper, one
+# Python version) measures ~300MB, and the volume is now shared across all
+# checkouts (see compose.yaml), so this covers several diverging branches.
+ENV CCACHE_DIR=/ccache
+ENV CCACHE_MAXSIZE=2G
+ENV PATH="/usr/lib/ccache:$PATH"
+
+# Non-root user matching the host UID/GID that bind-mounts the repo (default
+# 1000:1000, the common single-user-Linux-box case), so files the build
+# creates under the mount keep sane, non-root ownership on the host side.
+# Override with --build-arg USER_UID=$(id -u) --build-arg USER_GID=$(id -g)
+# if your host user has a different UID/GID.
+ARG USER_UID=1000
+ARG USER_GID=1000
+# groupadd fails outright if USER_GID is already taken by an existing
+# system group - which happens whenever a host's primary GID collides with
+# one baked into the rockylinux9 base image. The main real-world case is
+# macOS, where the default user's primary group is "staff" at GID 20, and
+# GID 20 is "games" on RHEL-family images. Only create the "builder" group
+# when that GID is actually free; otherwise useradd just attaches to
+# whichever group already owns it. Either way the builder user ends up
+# with the right GID for bind-mount ownership, which is all that matters.
+RUN (getent group "${USER_GID}" >/dev/null || groupadd -g "${USER_GID}" builder) \
+    && useradd -m -u "${USER_UID}" -g "${USER_GID}" -s /bin/bash builder \
+    && echo "builder ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/builder
+
+# Copied while still root: /bin is not writable by the builder user.
+COPY --from=ghcr.io/astral-sh/uv:0.11.27 /uv /uvx /bin/
+
+USER builder
+WORKDIR /__w/IfcOpenShell/IfcOpenShell
+
+# Installed as builder so managed Python interpreters land under builder's
+# $HOME, matching the user that actually runs the build.
+RUN uv python install
+
+CMD ["sleep", "infinity"]

docker/README.md

@@ -0,0 +1,78 @@
+Docker build environment
+========================
+
+This is a small utility to make it easy to compile a perfect `_ifcopenshell_wrapper.cpython-*-x86_64-linux-gnu.so`
+files.
+
+The reason for this tool is that I was trying to follow the web page directions, and my build was behaving differently
+to the release builds. Eventually I concluded that the differences between toolchains on the RHEL based rocky9 image
+and Ubuntu were just too great. Getting the build setup was already a lot of trial and error, so I thought I'd spend
+more time trying to reuse the github actions that perform the build, using a utility called `act`. I learnt a lot, in
+particular how much time, energy, and bandwidth Github waste. I also realised I was most of the way to a regular docker
+setup anyway, so I might as well just do that. So I've deconstructed all the github action steps, and turned it into
+a local docker build environment that uses the exact same base, tools, libraries, and build command/flags etc.
+
+Right now a Github action will:
+- launch the rocky9 base
+- upgrade all the packages
+- install a bunch of extra tools
+- do a recursive checkout of your repo
+- checkout the build repository
+- unpack dependencies
+- run the build script, making all python versions (5? right now I think)
+- create the .zip release files
+
+And it does _all_ of that _every_ time. This is not a fault of the action writers - it's just how Github seems to work.
+
+These dockers tools do the following differently, and it's actually a bit more powerful too:
+- build the base image once.
+- update the packages once.
+- install the extra tools once.
+- the repository is the one on your host, that gets bind mounted in the container as the working directory.
+- by adding an environment variable to .env, restricts to compiling for just a single python version.
+- when the build is finished the created files are right there under your local repositry (but not added to git) for
+  ease of access
+- each repository can have it's own build environment container.
+- the image is shared between those environments.
+- the containers share the ccache, so additional envs should get a helping hand.
+- it has a simple set of user friendly commands to drive it all.
+
+For example:
+``` bash
+# To see the commands (a superset of docker compose commands)
+./ifcos_env
+
+# Enable autocomplete of commands
+source .ifcos_env
+
+# First time commands
+./ifcos_env create
+./ifcos_env up
+./ifcos_env build
+
+# install and test library
+# find an issue
+# edit code
+./ifcos_env build
+
+# and so on. When done stop and optionally delete the container
+./ifcos_env stop
+./ifcos_env remove
+```
+
+To limit the build to one python version just add
+``` bash
+PY_TGT=py-311
+```
+or whichever version your Blender requires.
+
+You might see UNIQUE_ID in the .env file too. This keeps containers for separate folders, separate.
+
+System requirements
+1. Linux-x64 only at this time.
+2. Docker and docker-compose need to be installed.
+3. Have a good amount of disk space. (image is in /var (typically the root partition) and will be about 1.7 GB)
+4. The build action will create about 10GB in your repository folder. Make sure this partition is spacious
+   particularly if you intent on having multiple clones building.
+5. ... I think that covers most of it.
+

docker/SKILL.md

@@ -0,0 +1,186 @@
+---
+name: ifcopenshell-docker-build
+description: >-
+  Build a real ifcopenshell_wrapper (.so + .py) and IfcConvert locally via
+  the docker/ifcos_env toolchain, then wire them into a checkout for
+  running C++-dependent parts of the test suite (geometry, the SWIG
+  wrapper stub, the C++ parser). Use whenever a task needs to compile
+  IfcOpenShell's C++ core rather than just read/patch source - e.g.
+  reproducing or fixing a bug in src/ifcgeom, src/ifcparse, src/ifcwrap,
+  or validating util/scripts/validate_stub.py against the actual
+  generated wrapper.
+---
+
+# Building IfcOpenShell locally with docker/ifcos_env
+
+`docker/` mirrors the project's GitHub Actions build environment locally,
+in a persistent, non-root container with ccache so repeat builds are fast.
+See `docker/README.md` for the design rationale. Pure-Python changes don't
+need any of this - only reach for it when you need a real compiled
+`_ifcopenshell_wrapper*.so` or `IfcConvert` binary.
+
+## Placement
+
+This `docker/` folder must live as a direct child of the repo root you want
+to build (sibling of `src/`, `cmake/`, etc.) - `compose.yaml` and
+`ifcos_env` resolve the repo via `../` relative to wherever `docker/`
+itself sits, and bind-mount it into the container. If you're setting this
+up in a fresh clone, copy the whole `docker/` directory there first.
+
+## Setup
+
+```bash
+cd docker
+./ifcos_env create   # build the image (shared by name across all your clones/checkouts, so usually instant after the first time anywhere)
+./ifcos_env up        # create + start the container, clone/unpack the third-party dependency cache (~10GB, one-time per container)
+./ifcos_env build     # full build: all deps + IfcParse + IfcGeom + IfcConvert + the Python wrapper, for one Python version
+```
+
+`PY_TGT` and `UNIQUE_ID` live in `docker/.env` - `PY_TGT` (e.g. `py-311`)
+restricts the build to one Python version instead of building five;
+`UNIQUE_ID` is a hash of the folder path, recalculated on every `up`, so
+each checkout gets its own container/volumes automatically.
+
+A full first build takes ~1.5 hours (mostly compiling IfcOpenShell's own
+C++, not the cached third-party deps). After that, ccache makes incremental
+rebuilds of a couple of touched `.cpp` files **under a minute**.
+
+## Container lifecycle
+
+The container is long-lived (`sleep infinity`) so exec'd commands and
+ccache state persist between builds. Commands map directly onto Docker
+Compose's own container-vs-image distinction:
+
+```bash
+./ifcos_env up         # create the container if it doesn't exist, then start it (runs ready_repo too)
+./ifcos_env stop       # stop the container, keep it around
+./ifcos_env start      # start it back up (same container, same filesystem layer)
+./ifcos_env restart    # stop, then start
+./ifcos_env down       # remove the container (and its network) entirely
+./ifcos_env recreate   # down, then up - a fresh container
+```
+
+Named volumes (`ccache`) and the bind-mounted repo/`build/` are unaffected
+by `down`/`recreate` - only the container itself goes away, and `up`
+recreates it from the image.
+
+## Fast iteration
+
+Pass a target to `build` to skip the parts you don't need:
+
+```bash
+./ifcos_env build IfcConvert           # only the executables (IfcConvert, IfcGeomServer) - skips the Python wrapper entirely
+./ifcos_env build IfcOpenShell-Python  # only the SWIG Python wrapper - skips executables entirely
+./ifcos_env build                      # no target = everything (needed the first time, or after touching shared headers)
+```
+
+Use this to keep the edit -> rebuild -> test loop fast when debugging: if
+you're only touching `src/ifcgeom/`, build `IfcConvert`; if you're only
+exercising the Python API, build `IfcOpenShell-Python`.
+
+## Where the artifacts land
+
+Build output goes to `<repo_root>/build/Linux/x86_64/install/` on the host
+(bind-mounted, not just inside the container), owned by you (see
+"Container user" below):
+
+- `ifcopenshell/bin/IfcConvert` - the CLI binary
+- `python-<version>/lib/python<X.Y>/site-packages/ifcopenshell/_ifcopenshell_wrapper*.so`
+  and `ifcopenshell_wrapper.py` - the compiled wrapper + its generated
+  Python glue
+
+## Testing against a checkout (automated / AI-driven)
+
+`_ifcopenshell_wrapper*.so` and `ifcopenshell_wrapper.py` are already
+gitignored under `src/ifcopenshell-python/ifcopenshell/`, which is exactly
+where a normal in-tree build would put them - copy the two files there:
+
+```bash
+SRC=build/Linux/x86_64/install/python-3.11.8/lib/python3.11/site-packages/ifcopenshell
+cp "$SRC/_ifcopenshell_wrapper.cpython-311-x86_64-linux-gnu.so" src/ifcopenshell-python/ifcopenshell/
+cp "$SRC/ifcopenshell_wrapper.py" src/ifcopenshell-python/ifcopenshell/
+```
+
+Then, to run the test suite against it:
+
+```bash
+export PATH="$PWD/build/Linux/x86_64/install/ifcopenshell/bin:$PATH"   # for IfcConvert-dependent tests
+cd src/ifcopenshell-python/test
+PYTHONPATH="$PWD/.." python3.11 -m pytest -p no:pytest-blender .
+```
+
+(`-p no:pytest-blender` avoids the pytest-blender plugin trying to find a
+`blender` executable and failing collection entirely, even for non-Blender
+tests.) You'll need the matching Python version's `pip install`s too
+(numpy, shapely, isodate, lark, tabulate, pytest, ... - whatever the
+modules under test import) since this is a bare interpreter, not the
+project's pixi env.
+
+**This is the pattern to use for automated or AI-driven verification.**
+Don't use `try` (below) for that - it overwrites files in a real, live
+Blender installation, which isn't something an automated/AI workflow
+should ever do without the human explicitly asking for it in the moment.
+
+## Testing in Blender itself (human only)
+
+`try` copies the built wrapper straight into your actual Blender/Bonsai
+extension install, for manual in-Blender testing:
+
+```bash
+./ifcos_env try
+```
+
+It reads `BLENDER_USER_RESOURCE` from `.env` - set this to wherever
+Blender's user resource folder for the Bonsai extension actually lives on
+your system, which depends on your own Blender setup:
+
+```bash
+# in docker/.env
+BLENDER_USER_RESOURCE=~/.config/blender/bonsai/
+```
+
+`try` figures out the built Python version from `build/.../install/`
+(disambiguating with `PY_TGT` if more than one version was built) and
+copies the wrapper to
+`$BLENDER_USER_RESOURCE/extensions/.local/lib/python<X.Y>/site-packages/ifcopenshell/`.
+
+## Container user
+
+The image runs as a non-root `builder` user, UID/GID matching your host
+account (passed as `--build-arg` by `create` from `id -u`/`id -g`, so it
+adjusts automatically - no manual flag needed even if you're not 1000:1000).
+Files the build creates under the bind mount come out owned by you, not
+root. Passwordless `sudo` is available inside the container (e.g. via
+`attach`) for the rare case you need root for something ad hoc.
+
+If you're picking up an existing checkout that was previously built with
+an older, root-based image, you may hit `Permission denied` the first time
+you run `up`/`build` under the new image - `build/`, `.git/modules/`, the
+`ccache` volume, `output/`, and `build.log` can all be left root-owned from
+before. Fix it once via the container's own root (no host `sudo` needed):
+
+```bash
+docker exec -u root -w /__w/IfcOpenShell/IfcOpenShell <container-name> \
+    chown -R "$(id -u)":"$(id -g)" .git/modules build output build.log /ccache
+```
+
+(`<container-name>` is `ifcopenshell-<UNIQUE_ID>` - see `docker ps -a`.)
+
+## Other things worth knowing
+
+- **Linux x64 only.** `compose.yaml` pins `platform: linux/amd64`; on an
+  ARM host (e.g. Apple Silicon) this build isn't available.
+- **The final "Package .zip archives" step of `build()` has a pre-existing
+  bash syntax error**, unrelated to compilation - the actual build already
+  succeeded by that point (look for `Built IfcOpenShell...` in the output),
+  so this is safe to ignore if you only need the raw artifacts under
+  `build/.../install/`, not packaged release zips.
+- **`test_mmaped_stream` and similar `USE_MMAP`-dependent tests will fail**
+  against this build - `nix/build-all.py` is invoked with `USE_MMAP=OFF`
+  here. Not a bug in your code if you see it fail.
+- Only the bind-mounted `<repo>/build` lives on the host filesystem your
+  repo is checked out on. Anything the container writes *outside* that
+  mount lives in the container's own writable layer under Docker's data
+  root (commonly `/var/lib/docker`, i.e. usually your root partition) -
+  keep an eye on `df -h /` if you're running several of these containers
+  at once.

docker/compose.yaml

@@ -0,0 +1,15 @@
+name: ifcopenshell-${UNIQUE_ID}
+services:
+  ifcopenshell:
+    container_name: ifcopenshell-${UNIQUE_ID}
+    image: ifcopenshell-build-env:updated
+    platform: linux/amd64
+    volumes:
+      - type: bind
+        source: ../
+        target: /__w/IfcOpenShell/IfcOpenShell
+      - ccache:/ccache
+
+volumes:
+  ccache:
+    name: ifcopenshell-ccache-shared

docker/ifcos_env

@@ -0,0 +1,339 @@
+#!/bin/bash
+
+# ================== CONFIG ==================
+SCRIPT_NAME=$(basename "$0")
+ENV_FILE=".env"
+WORKDIR="/__w/IfcOpenShell/IfcOpenShell"
+NAMEPREFIX=ifcopenshell
+
+function set_env() {
+    # Load .env file if it exists
+    if [[ -f "$ENV_FILE" ]]; then
+        set -a
+        source "$ENV_FILE"
+        set +a
+        echo "✅ Loaded environment variables from $ENV_FILE"
+    else
+        echo "⚠️  No $ENV_FILE found, proceeding without it."
+    fi
+}
+
+set_env
+
+# ================ FUNCTIONS =================
+
+function create() {
+    echo "⭐ Creating image: ifcopenshell-build-env"
+    docker build -f Dockerfile \
+        --build-arg USER_UID="$(id -u)" --build-arg USER_GID="$(id -g)" \
+        -t ifcopenshell-build-env:updated .
+}
+
+function update() {
+    # The Dockerfile always builds FROM a clean rockylinux:9 and does
+    # `dnf update -y` as its first step, so re-running create() is enough
+    # to get fresh packages.
+    echo "⚡ Updating image: ifcopenshell-build-env"
+    create
+}
+
+function up() {
+    # Creates the container if it doesn't exist yet (and starts it either
+    # way) - this is the one that needs ready_repo, since a freshly created
+    # container has no submodules/dependency cache in place yet.
+    echo "🚀 Creating/starting stack: ifcopenshell-${UNIQUE_ID}"
+    unique          # Update UNIQUE_ID first
+    docker compose up -d "$@"   # Container must exist before ready_repo can exec into it.
+    ready_repo      # Ensure repo is recursive, and the build repo is in place.
+}
+
+function down() {
+    # Removes the container (and its network) entirely. Named volumes
+    # (ccache) and the bind-mounted repo/build/ survive; up() will recreate
+    # the container from scratch next time.
+    echo "🔥 Removing stack: ifcopenshell-${UNIQUE_ID}"
+    docker compose down "$@"
+}
+
+function stop() {
+    # Stops the existing container without removing it - the container,
+    # its filesystem layer, and its exec history all remain intact.
+    echo "🛑 Stopping stack: ifcopenshell-${UNIQUE_ID}"
+    docker compose stop "$@"
+}
+
+function start() {
+    # Starts a previously-stopped container back up. Does nothing (and
+    # won't create anything) if the container doesn't exist - use up() for
+    # that.
+    echo "▶️  Starting stack: ifcopenshell-${UNIQUE_ID}"
+    docker compose start "$@"
+}
+
+function restart() {
+    echo "🔄 Restarting stack (stop, then start)..."
+    stop
+    start
+}
+
+function recreate() {
+    echo "♻️  Recreating stack (down, then up)..."
+    down
+    up
+}
+
+function logs() {
+    echo "📜 Showing logs..."
+    docker compose logs -f "$@"
+}
+
+function ps() {
+    docker compose ps
+}
+
+function config() {
+    echo "🔍 Validated compose configuration:"
+    docker compose config
+}
+
+function remove() {
+    # Lower-level than down(): removes already-stopped containers without
+    # touching the compose network. Mostly useful after a plain stop().
+    echo "🗑️  Removing stopped containers: ifcopenshell-${UNIQUE_ID}"
+    docker compose rm "$@"
+}
+
+function unique() {
+    echo "🔧 Making stack name folder specific..."
+
+    REGEX="^UNIQUE_ID="
+
+    if [[ ! -f "$ENV_FILE" ]] || ! grep -qE "$REGEX" "$ENV_FILE"; then
+        echo -e "\nUNIQUE_ID=dummy\n" >> "$ENV_FILE"
+    fi
+
+    export UNIQUE_ID="$(pwd | sha256sum | cut -c -8)"
+
+    # `sed -i` takes incompatible syntax between GNU sed (Linux) and BSD sed
+    # (macOS) - `-si` is GNU-only and errors as "illegal option -- s" under
+    # BSD/macOS sed. Avoid -i altogether and do the in-place edit via a temp
+    # file + mv instead, which behaves identically with either sed.
+    local tmp_file
+    tmp_file="$(mktemp "${ENV_FILE}.XXXXXX")"
+    sed "s/^UNIQUE_ID=.*$/UNIQUE_ID=${UNIQUE_ID}/" "$ENV_FILE" > "$tmp_file"
+    mv "$tmp_file" "$ENV_FILE"
+
+    set_env
+}
+
+function ready_repo() {
+    echo "👍 Getting the repo ready to build..."
+    docker exec -i -w "${WORKDIR}" "${NAMEPREFIX}-${UNIQUE_ID}" bash -c '
+        set -euo pipefail   # Recommended for robustness
+
+        git submodule update --init --recursive
+
+        if [[ ! -d "build" ]]; then
+            git clone -b rockylinux9-x64 https://github.com/IfcOpenShell/build-outputs.git build
+        else
+            cd build
+            git pull
+            cd ..
+        fi
+
+        if [[ ! -d "build/Linux/x86_64/install/boost-1.86.0/" ]]; then
+            cd build
+            uv run ../nix/cache_dependencies.py unpack
+            cd ..
+        fi
+    '
+}
+
+function build() {
+    echo "☕ Execute the build, go make yourself a cuppa... I'll be a while"
+    local BUILD_TARGET="$1"
+    
+    docker exec -i -w "${WORKDIR}" -e PY_TGT="${PY_TGT}" -e BUILD_TARGET="${BUILD_TARGET}" "${NAMEPREFIX}-${UNIQUE_ID}" bash -c '
+        set -o pipefail
+        CXXFLAGS="-O3" CFLAGS="-O3 ${DARWIN_C_SOURCE}" ADD_COMMIT_SHA=1 BUILD_CFG=Release uv run ./nix/build-all.py -v ${PY_TGT:+-$PY_TGT} --diskcleanup ${BUILD_TARGET} 2>&1 | tee build.log
+    '
+    echo "🎒 Pack Dependencies"
+    docker exec -i -w "${WORKDIR}" "${NAMEPREFIX}-${UNIQUE_ID}" bash -c '
+        cd build
+        uv run ../nix/cache_dependencies.py pack
+    '
+
+    echo "🎁 Package .zip archives"
+    docker exec -i -w "${WORKDIR}" -e GITHUB_SHA="$(git rev-parse HEAD)" "${NAMEPREFIX}-${UNIQUE_ID}" bash -c '
+        OUTPUT_DIR=${PWD}/output
+        VERSION=v`cat VERSION`
+        mkdir -p ${OUTPUT_DIR}
+        cd ./build/`uname`/*/install/ifcopenshell
+
+        ls -d python-* | while read py_version; do
+            postfix=`echo ${py_version: -1} | sed s/[0-9]//`
+            numbers=`echo $py_version | grep -oE "[0-9]+\.[0-9]+" | tr -d "."`
+            py_version_major=python-${numbers}$postfix
+            pushd . > /dev/null
+            cd $py_version
+            if [ ! -d ifcopenshell ]; then
+                mkdir ../ifcopenshell_
+                mv * ../ifcopenshell_
+                mv ../ifcopenshell_ ifcopenshell
+            fi
+            [ -d ifcopenshell/__pycache__ ] && rm -rf ifcopenshell/__pycache__
+            find ifcopenshell -name "*.pyc" -delete
+            zip -r -qq ifcopenshell-${py_version_major}-${VERSION}-${GITHUB_SHA:0:7}-linux64.zip ifcopenshell/*
+            mv *.zip ${OUTPUT_DIR}/
+            popd > /dev/null
+        done
+
+        cd bin
+        if compgen -G "./*.zip" > /dev/null; then
+            rm *.zip 2>&1 >/dev/null || true
+        ls | while read exe; do
+            zip -qq -r ${exe}-${VERSION}-${GITHUB_SHA:0:7}-linux64.zip $exe
+        done
+        mv *.zip ${OUTPUT_DIR}/
+        cd ..
+      '
+}
+
+function attach() {
+    echo "🔦 Connect to interactive shell"
+    docker exec -it  -w "${WORKDIR}" "${NAMEPREFIX}-${UNIQUE_ID}" /bin/bash
+}
+
+function try() {
+    # Copies the freshly built wrapper into your actual Blender/Bonsai
+    # installation for manual, in-Blender testing. This is a human-only
+    # convenience: it overwrites files in your live Blender setup, so it's
+    # not something that should run unattended as part of an automated or
+    # AI-driven build/test loop (which should instead copy the wrapper into
+    # the repo's own src/ifcopenshell-python/ifcopenshell/ - see SKILL.md).
+    echo "🚴 Copying build artifacts into your Blender resource folder for testing"
+
+    if [[ -z "${BLENDER_USER_RESOURCE:-}" ]]; then
+        echo "❌ BLENDER_USER_RESOURCE is not set in .env."
+        echo "   Add a line pointing at wherever Blender's user resource folder for"
+        echo "   the Bonsai extension actually is on your system, e.g.:"
+        echo "     BLENDER_USER_RESOURCE=~/.config/blender/bonsai/"
+        return 1
+    fi
+
+    # Normalise: expand a leading ~ (in case it was quoted in .env and so
+    # never went through shell tilde-expansion when set_env sourced it),
+    # then resolve to an absolute, symlink-free path.
+    local resource="${BLENDER_USER_RESOURCE/#\~/$HOME}"
+    resource="$(realpath -m "$resource")"
+
+    local install_dir="../build/Linux/x86_64/install"
+    local py_dirs=("$install_dir"/python-*)
+    if [[ ${#py_dirs[@]} -gt 1 && -n "${PY_TGT:-}" ]]; then
+        # PY_TGT is compact (py-311); the install dirs are dotted
+        # (python-3.11.8) - reinsert the dot (assumes a single-digit major
+        # version, true for the Python 3.x line) before matching.
+        local py_tgt_digits="${PY_TGT#py-}"
+        local py_tgt_dotted="${py_tgt_digits:0:1}.${py_tgt_digits:1}"
+        local filtered=() d
+        for d in "${py_dirs[@]}"; do
+            [[ "$(basename "$d")" == "python-${py_tgt_dotted}."* ]] && filtered+=("$d")
+        done
+        [[ ${#filtered[@]} -gt 0 ]] && py_dirs=("${filtered[@]}")
+    fi
+    if [[ ${#py_dirs[@]} -ne 1 || ! -d "${py_dirs[0]}" ]]; then
+        echo "❌ Expected exactly one built python-* dir under $install_dir, found ${#py_dirs[@]}."
+        echo "   Run 'build' first, or set PY_TGT in .env to disambiguate a multi-version build."
+        return 1
+    fi
+
+    local py_minor
+    py_minor="$(basename "${py_dirs[0]}" | grep -oE '[0-9]+\.[0-9]+')"
+    local wrapper_dir="${py_dirs[0]}/lib/python${py_minor}/site-packages/ifcopenshell"
+    if [[ ! -f "$wrapper_dir/ifcopenshell_wrapper.py" ]]; then
+        echo "❌ Built wrapper not found at $wrapper_dir - run 'build' first."
+        return 1
+    fi
+
+    local target="$resource/extensions/.local/lib/python${py_minor}/site-packages/ifcopenshell"
+    mkdir -p "$target"
+    cp "$wrapper_dir"/_ifcopenshell_wrapper*.so "$target/"
+    cp "$wrapper_dir"/ifcopenshell_wrapper.py "$target/"
+    echo "✅ Copied wrapper into $target"
+}
+
+function clean() {
+    # Host-side only - doesn't touch the container, image, or ccache volume.
+    echo "💎 Clean the build and output folder up"
+    if [[ -d "../build" ]]; then
+        rm -rf ../build
+    fi
+    if [[ -d "../output" ]]; then
+        rm -rf ../output
+    fi
+}
+
+
+function help() {
+    cat <<EOF
+Usage: ./$SCRIPT_NAME <command>
+
+Available commands:
+  create      Build the rocky9-based image
+  update      Rebuild the image fresh, picking up OS package updates
+  up          Create the container if it doesn't exist yet, and start it
+  down        Remove the container entirely (docker compose down)
+  stop        Stop the container without removing it
+  start       Start a previously-stopped container
+  restart     stop, then start (same container, no recreation)
+  recreate    down, then up (fresh container)
+  build       Execute the IfcOpenShell build
+  attach      Connect to an interactive shell in the container
+  try         Copy the built wrapper into your Blender resource folder
+              (human-only - see BLENDER_USER_RESOURCE below, and SKILL.md
+              for the AI/automated-testing equivalent)
+  clean       Remove the build and output folders
+  logs        Follow container logs
+  ps          Show running containers
+  config      Validate and show compose config
+  remove      Remove stopped containers (docker compose rm)
+  help        Show this help
+
+Environment variables from .env are automatically loaded, including:
+  PY_TGT                  Restrict the build to one Python version, e.g. py-311
+  UNIQUE_ID               Recalculated automatically on every 'up', don't set by hand
+  BLENDER_USER_RESOURCE   Where 'try' copies the wrapper for manual testing, e.g.
+                          ~/.config/blender/bonsai/
+EOF
+}
+
+# ================= MAIN =================
+
+case "$1" in
+    create)         create ;;
+    update)         update ;;
+    up)             up "${@:2}" ;;
+    down)           down "${@:2}" ;;
+    stop)           stop "${@:2}" ;;
+    start)          start "${@:2}" ;;
+    restart)        restart ;;
+    recreate)       recreate ;;
+    build)          build "${@:2}" ;;
+    attach)         attach ;;
+    try)            try ;;
+    clean)          clean ;;
+    logs)           logs "${@:2}" ;;
+    ps)             ps ;;
+    config)         config ;;
+    remove)         remove ;;
+    help|-h|--help) help ;;
+    "")
+        echo "❌ No command provided."
+        help
+        ;;
+    *)
+        echo "❌ Unknown command: $1"
+        echo "Type './$SCRIPT_NAME help' for available commands."
+        exit 1
+        ;;
+esac

nix/build-all.py

@@ -50,7 +50,7 @@ Used environment variables:
     - ``NO_CLEAN`` - do not clean `ifcopenshell` build directories but continue working on current build
     (installed dependencies are never cleared).
     By default option is disabled, to enable pass any value from `1`, `on`, `true`.
-    - ``IFCOS_SCHEMAS`` - schemas to be built; defaults to cmake default (IFC2X3; IFC4; IFC4X3_ADD2) - to be supplied as `2x3;4`
+    - ``IFCOS_SCHEMAS`` - schemas to be built; defaults to cmake default (8 schemas), to be supplied as `2x3;4;4x3_add2`
     - ``USE_OCCT`` - whether to use official Open CASCADE instead of Community Edition
     (`true` by default, any other value is considered `false`)
     - ``WASM_PYTHON_PATH`` - path to WASM Python installation,
@@ -155,7 +155,7 @@ MPFR_VERSION = "3.1.6"  # latest is 4.1.0
 CGAL_VERSION = "v5.6.3"
 USD_VERSION = "23.05"
 TBB_VERSION = "2021.9.0"
-ROCKSDB_VERSION = "9.11.2"
+ROCKSDB_VERSION = "10.4.2"
 ZSTD_VERSION = "1.5.7"
 # binaries
 cp = "cp"
@@ -627,9 +627,10 @@ def build_dependency(
     build_tool_args: "list[str]",
     download_url: str,
     download_name: str,
+    *,
     download_tool: Literal["py", "git"] = download_tool_default,
     revision: "Union[str, None]" = None,
-    patch: "Union[str, list[str], None]" = None,
+    patch: list[str] | None = None,
     shell=None,
     pre_compile_subs: "Sequence[tuple[str, str, str]]" = (),
     additional_files: "Union[dict[str, str], None]" = None,
@@ -714,8 +715,6 @@ def build_dependency(
                 urlretrieve(url, os.path.join(extract_dir, path))
 
     if patch is not None:
-        if isinstance(patch, str):
-            patch = [patch]
         for p in patch:
             patch_abs = (SCRIPT_PATH / p).absolute().__str__()
             if os.path.exists(patch_abs):
@@ -724,6 +723,8 @@ def build_dependency(
                 except Exception as e:
                     # Assert that the patch has already been applied
                     run(["patch", "-p1", "--batch", "--reverse", "--dry-run", "-i", patch_abs], cwd=extract_dir)
+            else:
+                raise FileNotFoundError(patch_abs)
 
     if shell is not None:
         sp.run(shell, shell=True, check=True, cwd=extract_dir)
@@ -1171,6 +1172,14 @@ if "cgal" in targets:
         os.environ["CC"] = MAC_CROSS_COMPILE_INTEL_CC
         gmp_args.extend(MAC_CROSS_COMPILE_INTEL_AUTOCONF_HOST_ARGS)
 
+    # Fixes configure failing to find a working compiler under GCC 15's default -std=gnu23.
+    # Issue presumably will be resolved in any next gmp version, but currently the last one is 6.3.0.
+    # Patch is just applying fix from upstream meantion below:
+    # https://gmplib.org/list-archives/gmp-bugs/2025-February/005561.html
+    gmp_patches = ["./patches/gmp/001-fix-std23.patch"]
+    if GMP_VERSION != "6.3.0":
+        raise Exception(f"GMP_VERSION changed to {GMP_VERSION}, check whether {gmp_patches} is still needed.")
+
     build_dependency(
         name=f"gmp-{GMP_VERSION}",
         mode="autoconf",
@@ -1178,6 +1187,7 @@ if "cgal" in targets:
         pre_compile_subs=(
             [("build/config.h", "HAVE_OBSTACK_VPRINTF 1", "HAVE_OBSTACK_VPRINTF 0")] if "wasm" in flags else []
         ),
+        patch=gmp_patches,
         # Sometimes ftp.gnu.org is very slow, use ftpmirror.gnu.org as a workaround.
         download_url="https://ftpmirror.gnu.org/gnu/gmp/",
         download_name=f"gmp-{GMP_VERSION}.tar.bz2",

nix/patches/gmp/001-fix-std23.patch

@@ -0,0 +1,27 @@
+Fixes configure failing to find a working compiler under GCC 15's default
+-std=gnu23 (upstream fix: https://gmplib.org/repo/gmp/rev/8e7bb4ae7a18).
+
+Upstream fix is patching `acinclude.m4`, but since in the release tarball
+all macros are already expanded to `configure` script, so we're patching
+all occurrences of that macro.
+
+--- a/configure
++++ b/configure
+@@ -6568,7 +6568,7 @@
+
+ #if defined (__GNUC__) && ! defined (__cplusplus)
+ typedef unsigned long long t1;typedef t1*t2;
+-void g(){}
++void g(int,t1 const*,t1,t2,t1 const*,int){}
+ void h(){}
+ static __inline__ t1 e(t2 rp,t2 up,int n,t1 v0)
+ {t1 c,x,r;int i;if(v0){c=1;for(i=1;i<n;i++){x=up[i];r=x+1;rp[i]=r;}}return c;}
+@@ -8187,7 +8187,7 @@
+
+ #if defined (__GNUC__) && ! defined (__cplusplus)
+ typedef unsigned long long t1;typedef t1*t2;
+-void g(){}
++void g(int,t1 const*,t1,t2,t1 const*,int){}
+ void h(){}
+ static __inline__ t1 e(t2 rp,t2 up,int n,t1 v0)
+ {t1 c,x,r;int i;if(v0){c=1;for(i=1;i<n;i++){x=up[i];r=x+1;rp[i]=r;}}return c;}

nix/patches/occt/88af392.patch

@@ -1,32 +0,0 @@
-http://git.dev.opencascade.org/gitweb/?p=occt.git;a=commitdiff;h=0ab4e621833f4eae945a3762c9a29ee12e2eec53#patch1
-diff --git a/src/HLRBRep/HLRBRep_InternalAlgo.cxx b/src/HLRBRep/HLRBRep_InternalAlgo.cxx
-index ca885ca..c13cb06 100644 (file)
---- a/src/HLRBRep/HLRBRep_InternalAlgo.cxx
-+++ b/src/HLRBRep/HLRBRep_InternalAlgo.cxx
-@@ -165,7 +165,7 @@ void HLRBRep_InternalAlgo::Update ()
-       SB.Bounds(v1,v2,e1,e2,f1,f2);
- 
-       for (Standard_Integer e = e1; e <= e2; e++) {
--        HLRBRep_EdgeData ed = aEDataArray.ChangeValue(e);
-+        HLRBRep_EdgeData& ed = aEDataArray.ChangeValue(e);
-         HLRAlgo::DecodeMinMax(ed.MinMax(), TheMin, TheMax);
-        if (FirstTime) {
-          FirstTime = Standard_False;
-@@ -307,7 +307,7 @@ void HLRBRep_InternalAlgo::InitEdgeStatus ()
-   Standard_Integer nf = myDS->NbFaces();
- 
-   for (Standard_Integer e = 1; e <= ne; e++) {
--    HLRBRep_EdgeData ed = aEDataArray.ChangeValue(e);
-+    HLRBRep_EdgeData& ed = aEDataArray.ChangeValue(e);
-     if (ed.Selected()) ed.Status().ShowAll();
-   }
- //  for (Standard_Integer f = 1; f <= nf; f++) {
-@@ -368,7 +368,7 @@ void HLRBRep_InternalAlgo::Select ()
-     Standard_Integer nf = myDS->NbFaces();
-     
-     for (Standard_Integer e = 1; e <= ne; e++) {
--      HLRBRep_EdgeData ed = aEDataArray.ChangeValue(e);
-+      HLRBRep_EdgeData& ed = aEDataArray.ChangeValue(e);
-       ed.Selected(Standard_True);
-     }
-     

nix/patches/pr622.patch

@@ -1,22 +0,0 @@
-From a0deb4ce8b43cf3c8b8c0a4225c6be5296446dbd Mon Sep 17 00:00:00 2001
-From: Adam Eri <adam.eri@blackmirror.media>
-Date: Tue, 3 Sep 2019 23:30:20 +0200
-Subject: [PATCH] Resolves compile error on macOS
-
-Resolves "no member named 'isnan' in namespace 'std'" on macOS
----
- GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp b/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-index 1f9a3eef..dd6f5c59 100644
---- a/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-+++ b/GeneratedSaxParser/src/GeneratedSaxParserUtils.cpp
-@@ -10,6 +10,7 @@
- 
- #include "GeneratedSaxParserUtils.h"
- #include <math.h>
-+#include <cmath>
- #include <memory>
- #include <string.h>
- #include <limits>

pyproject.toml

@@ -1,13 +1,8 @@
 [project]
 name = "IfcOpenShell"
 version = "0.0.0"
-dependencies = [
-    "black==26.3.1",
-    "ruff==0.15.12",
-    "poethepoet",
-    "ty==0.0.32",
-    "gersemi==0.26.1",
-]
+# Don't provide requires-python explicitly
+# allowing pyprojects to set their own (e.g. bonsai and general ifcopenshell version differ).
 
 [tool.black]
 line-length = 120
@@ -43,6 +38,7 @@ exclude = [
 # then they will be inherited by projects' .toml files.
 # This allows using assuming different Python version for different projects.
 [tool.ruff]
+line-length = 120
 exclude = [
     # Submodules.
     "src/ifcopenshell-python/ifcopenshell/express",
@@ -83,92 +79,39 @@ ignore = [
 ]
 
 [tool.ty.rules]
-all = "ignore"
+all = "error"
 
 # Structural rules (no deep type inference needed, easier to adapt).
-abstract-method-in-final-class = "error"
-ambiguous-protocol-member = "error"
-conflicting-declarations = "error"
-conflicting-metaclass = "error"
-cyclic-class-definition = "error"
-cyclic-type-alias-definition = "error"
-dataclass-field-order = "error"
-duplicate-base = "error"
-duplicate-kw-only = "error"
-empty-body = "error"
-escape-character-in-forward-annotation = "error"
-final-on-non-method = "error"
-final-without-value = "error"
-ignore-comment-unknown-rule = "error"
-implicit-concatenated-string-type-annotation = "error"
-inconsistent-mro = "error"
-ineffective-final = "error"
-instance-layout-conflict = "error"
-invalid-dataclass = "error"
-invalid-dataclass-override = "error"
-invalid-enum-member-annotation = "error"
-invalid-explicit-override = "error"
-invalid-frozen-dataclass-subclass = "error"
-invalid-generic-class = "error"
-invalid-generic-enum = "error"
-invalid-ignore-comment = "error"
-invalid-legacy-positional-parameter = "error"
-invalid-legacy-type-variable = "error"
-invalid-named-tuple = "error"
-invalid-newtype = "error"
-invalid-overload = "error"
-invalid-paramspec = "error"
-invalid-protocol = "error"
-invalid-syntax-in-forward-annotation = "error"
-invalid-total-ordering = "error"
-invalid-type-alias-type = "error"
-invalid-type-checking-constant = "error"
-invalid-type-guard-definition = "error"
-invalid-type-variable-bound = "error"
-invalid-type-variable-constraints = "error"
-invalid-typed-dict-header = "error"
-invalid-typed-dict-statement = "error"
-override-of-final-method = "error"
-override-of-final-variable = "error"
-possibly-missing-import = "error"
-possibly-missing-submodule = "error"
 # Has false positives due to ty walrus operator bug.
-# possibly-unresolved-reference = "error"
-raw-string-type-annotation = "error"
-redundant-final-classvar = "error"
-shadowed-type-variable = "error"
-subclass-of-final-class = "error"
-super-call-in-named-tuple-method = "error"
-unavailable-implicit-super-arguments = "error"
-unbound-type-variable = "error"
-undefined-reveal = "error"
-unresolved-global = "error"
-unresolved-import = "error"
-unresolved-reference = "error"
-unused-ignore-comment = "error"
-unused-type-ignore-comment = "error"
-useless-overload-body = "error"
+possibly-unresolved-reference = "ignore"
+# Maybe later, requires to specify element types for all generics.
+missing-type-argument = "ignore"
+# Conflicts with `bpy` props defined using annotations.
+invalid-type-form = "ignore"
 
 # Non-structural rules:
-deprecated = "error"
-zero-stepsize-in-slice = "error"
-possibly-missing-implicit-call = "error"
-unused-awaitable = "error"
-
-# Function argument rules:
 # Conflicts with `ifcopenshell.api.geometry.add_representation` type of callables we have, confusing them with a module.
-# call-non-callable = "error"
-conflicting-argument-forms = "error"
+call-non-callable = "ignore"
+# bpy is missing some context manager implementations.
+invalid-context-manager = "ignore"
+# Doesn't go well with `bpy.ops.xxx.yyy`.
+unresolved-attribute = "ignore"
 # Too many false positives.
-# invalid-argument-type = "error"
-missing-argument = "error"
-parameter-already-assigned = "error"
-positional-only-parameter-as-kwarg = "error"
-too-many-positional-arguments = "error"
-unknown-argument = "error"
-# Has a lot of warnings due to current ty walrus operator issues.
-# index-out-of-bounds = "error"
-# unresolved-attribute = "error"
+invalid-argument-type = "ignore"
+invalid-method-override = "ignore"
+invalid-assignment = "ignore"
+invalid-parameter-default = "ignore"
+missing-override-decorator = "ignore"
+invalid-yield = "ignore"
+invalid-return-type = "ignore"
+non-callable-init-subclass = "ignore"
+not-iterable = "ignore"
+possibly-missing-attribute = "ignore"
+no-matching-overload = "ignore"
+not-subscriptable = "ignore"
+unsupported-dynamic-base = "ignore"
+unsupported-operator = "ignore"
+type-assertion-failure = "ignore"
 
 [tool.ty.environment]
 extra-paths = [
@@ -215,6 +158,18 @@ exclude = [
 
 [tool.poe.tasks]
 
+dev-setup.sequence = [
+    {cmd = "uv sync"},
+    {cmd = "uv pip install -e ./src/bsdd/"},
+    {cmd = "uv pip install -e ./src/ifcopenshell-python/[advanced,dev]"},
+    {cmd = "uv pip install -e ./src/ifcedit/"},
+    {cmd = "uv pip install -e ./src/ifcpatch/"},
+    {cmd = "uv pip install -e ./src/ifcquery/"},
+    {cmd = "uv pip install -e './src/ifcmcp/[mcp]'"},
+    {cmd = "uv pip install -r src/bonsai/requirements-dev.txt"},
+]
+dev-setup.help = "Install repo packages in editable mode"
+
 ruff = "ruff check"
 
 black = "black ."
@@ -243,6 +198,7 @@ cmake-format = "gersemi . --in-place"
 # --ignore unresolved-reference: walrus operator false positives in ty.
 cmd = """
     ty check
+    nix/
     src/bcf
     src/bsdd
     src/ifc2ca

requirements-tools.txt

@@ -0,0 +1,5 @@
+black==26.3.1
+ruff==0.15.12
+poethepoet
+ty==0.0.59
+gersemi==0.26.1

src/bonsai/Makefile

@@ -106,7 +106,7 @@ endif
 endif # def PLATFORM
 
 # Current build commit hash.
-OLD:=1c5b825
+OLD:=3e7b739
 .PHONY: bump
 bump:
 ifndef NEW

src/bonsai/bonsai/bim/__init__.py

@@ -90,6 +90,7 @@ modules = {
     "web": None,
     "light": None,
     "alignment": None,
+    "clip_box": None,
     # Uncomment this line to enable loading of the demo module. Happy hacking!
     # The name "demo" must correlate to a folder name in `bim/module/`.
     # "demo": None,

src/bonsai/bonsai/bim/data/pset/EPset_Drawing.ifc

@@ -5,7 +5,7 @@ FILE_NAME('EPset_Drawing.ifc','2020-01-01T00:00:00',$,$,'EPset_Drawing','EPset_D
 FILE_SCHEMA(('IFC4'));
 ENDSEC;
 DATA;
-#1=IFCPROPERTYSETTEMPLATE('2JhNIvqZrFnAgxfhK0XVQX',$,'EPset_Drawing','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation/DRAWING',(#23,#22,#27,#24,#19,#12,#26,#9,#8,#7,#6,#4,#18,#11,#5,#20,#25,#14,#10,#17,#28,#16,#3,#21,#13,#15,#2));
+#1=IFCPROPERTYSETTEMPLATE('2JhNIvqZrFnAgxfhK0XVQX',$,'EPset_Drawing','',.PSET_OCCURRENCEDRIVEN.,'IfcAnnotation/DRAWING',(#23,#22,#27,#24,#29,#30,#19,#12,#26,#9,#8,#7,#6,#4,#18,#11,#5,#20,#25,#14,#10,#17,#28,#16,#3,#21,#13,#15,#2));
 #2=IFCSIMPLEPROPERTYTEMPLATE('23JavTMk98ZxXhrUEnjAcf',$,'TargetView','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #3=IFCSIMPLEPROPERTYTEMPLATE('1yVWUt5H9DAOuu0OaMMLpe',$,'Scale','The scale of this drawing represented as a numerator and denominator, such as 1/100',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #4=IFCSIMPLEPROPERTYTEMPLATE('3gsuPBtU93b8f0gg1pjkq6',$,'HumanScale','The scale of this drawing in human readable format, such as 1:100',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
@@ -33,5 +33,7 @@ DATA;
 #26=IFCSIMPLEPROPERTYTEMPLATE('2iwERDOW55Pf4hCbuFRe1Q',$,'FillMode','Method to fill areas seen in projection',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #27=IFCSIMPLEPROPERTYTEMPLATE('1YF$qLzBzF19Io8aB2N8cE',$,'CutMode','Method for cutting geometry',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
 #28=IFCSIMPLEPROPERTYTEMPLATE('1YSnFzurrEyRNtoLdmmddP',$,'BringToFront','The objects with these SVG classes will render in front of all other objects.Ex: IfcBeam, IfcColumn',.P_SINGLEVALUE.,'IfcText',$,$,$,$,$,.READWRITE.);
+#29=IFCSIMPLEPROPERTYTEMPLATE('0lP6Y8q9v2QhDnR4sT7uVx',$,'PerspectiveShiftX','Horizontal perspective camera shift stored as drawing metadata using Blender camera shift units.',.P_SINGLEVALUE.,'IfcReal',$,$,$,$,$,.READWRITE.);
+#30=IFCSIMPLEPROPERTYTEMPLATE('2mR8b1NcW5EoFyG7hJ9kLp',$,'PerspectiveShiftY','Vertical perspective camera shift stored as drawing metadata using Blender camera shift units.',.P_SINGLEVALUE.,'IfcReal',$,$,$,$,$,.READWRITE.);
 ENDSEC;
 END-ISO-10303-21;

src/bonsai/bonsai/bim/handler.py

@@ -47,10 +47,15 @@ from bonsai.bim.module.model.array import (
 )
 from bonsai.bim.module.model.data import AuthoringData
 from bonsai.bim.module.model.decorator import (
+    BendPreviewDecorator,
     BoundingBoxDecorator,
+    DoorSwingReadonlyDecorator,
+    MEPSegmentExtendPreviewDecorator,
+    MEPSystemPathDecorator,
     SlabDirectionDecorator,
     WallAxisDecorator,
     WallFilletPreviewDecorator,
+    WallSystemPathDecorator,
 )
 from bonsai.bim.module.model.wall import WallGizmoPreviewDecorator
 from bonsai.bim.module.nest.decorator import NestDecorator
@@ -315,9 +320,11 @@ def loadIfcStore(scene: bpy.types.Scene) -> None:
     IfcStore.purge()
     refresh_ui_data()
     if not tool.Ifc.get():
+        tool.Autosave.cancel_timer()
         return
     tool.Ifc.schema()
     IfcStore.relink_all_objects()
+    tool.Autosave.reset_timer()
 
 
 @persistent
@@ -510,8 +517,13 @@ def _install_viewport_overlays() -> None:
     NestDecorator.uninstall()
     WallAxisDecorator.uninstall()
     SlabDirectionDecorator.uninstall()
+    MEPSystemPathDecorator.uninstall()
+    WallSystemPathDecorator.uninstall()
     WallFilletPreviewDecorator.uninstall()
+    BendPreviewDecorator.uninstall()
+    MEPSegmentExtendPreviewDecorator.uninstall()
     WallGizmoPreviewDecorator.uninstall()
+    DoorSwingReadonlyDecorator.uninstall()
     ArrayPreviewDecorator.uninstall()
     ArraySelectionHighlightDecorator.uninstall()
     uninstall_decorator_cache_handlers()
@@ -526,16 +538,28 @@ def _install_viewport_overlays() -> None:
             WallAxisDecorator.install(bpy.context)
         if model_props.show_slab_direction:
             SlabDirectionDecorator.install(bpy.context)
+        if model_props.show_paths:
+            MEPSystemPathDecorator.install(bpy.context)
+            WallSystemPathDecorator.install(bpy.context)
         if model_props.show_bounding_box:
             BoundingBoxDecorator.install(bpy.context)
         # Always-installed: draw() self-polls on Scene.BIMPreviewProperties.
         # wall_fillet.is_active, so installation has no cost when no preview
         # is open. No corresponding addon-preference toggle.
         WallFilletPreviewDecorator.install(bpy.context)
+        # Always-installed siblings of WallFilletPreviewDecorator: each
+        # self-polls on its own scene.BIMPreviewProperties subgroup or on
+        # selection + hover gizmo state — zero cost when nothing is active.
+        BendPreviewDecorator.install(bpy.context)
+        MEPSegmentExtendPreviewDecorator.install(bpy.context)
         # Always-installed: draw_lines() self-polls on selection + hover state
         # for join / extend-to-wall / cursor-extend / cursor-split previews.
         # Free when no preview-eligible state is active.
         WallGizmoPreviewDecorator.install(bpy.context)
+        # Always-installed: draw() self-polls on active object + IfcDoor +
+        # parametric pset, so the cost is one bpy/IFC lookup per redraw when
+        # nothing eligible is selected.
+        DoorSwingReadonlyDecorator.install(bpy.context)
         # Always-installed: draw() self-polls on the active object's array
         # family membership, so installation has no cost when no array
         # element is selected.

src/bonsai/bonsai/bim/ifc.py

@@ -46,7 +46,7 @@ IFC_CONNECTED_TYPE = Union[bpy.types.Material, bpy.types.Object]
 class OperationData(TypedDict):
     id: int
     guid: NotRequired[str]
-    obj: str
+    obj: NotRequired[str]
 
 
 class EditObjectOperationData(TypedDict):
@@ -566,6 +566,19 @@ class IfcStore:
                 result = getattr(operator, "_modal")(context, event)
         except:
             bonsai.last_error = traceback.format_exc()
+            # An operator that mutated IFC then raised leaves the IFC graph captured
+            # by the transaction but the Blender side stale. Blender does not push an
+            # undo step for a raised operator (mirror of the CANCELLED-modal gap
+            # handled below), so we push one here so Ctrl+Z actually rewinds the
+            # partial mutation, then surface the recovery path to the user.
+            ifc_file = tool.Ifc.get()
+            if ifc_file and ifc_file.transaction and ifc_file.transaction.operations:
+                bpy.ops.ed.undo_push(message=f"Recover {operator.bl_idname}")
+                operator.report(
+                    {"WARNING"},
+                    "Operation partially completed (IFC changed, Blender state may be stale). "
+                    "Press Ctrl+Z to restore the previous state.",
+                )
             # Try to ensure undo will work since Blender undo does work in case of errors.
             # As error come unexpectedly, it's important that user might have a chance to save the file
             # before they got the error and not to lose the work they've done.

src/bonsai/bonsai/bim/import_ifc.py

@@ -223,6 +223,7 @@ class IfcImporter:
         self.elements: set[ifcopenshell.entity_instance] = set()
         self.annotations: set[ifcopenshell.entity_instance] = set()
         self.gross_elements: set[ifcopenshell.entity_instance] = set()
+        self.broken_arrays: set[ifcopenshell.entity_instance] = set()
         self.element_types: set[ifcopenshell.entity_instance] = set()
         self.spatial_elements: set[ifcopenshell.entity_instance] = set()
         self.meshes: dict[str, OBJECT_DATA_TYPE] = {}
@@ -979,8 +980,13 @@ class IfcImporter:
                     if unit.Name == "METRE":
                         if not unit.Prefix:
                             bpy.context.scene.unit_settings.length_unit = "METERS"
-                        else:
+                        elif f"{unit.Prefix}METERS" in ("KILOMETERS", "CENTIMETERS", "MILLIMETERS", "MICROMETERS"):
                             bpy.context.scene.unit_settings.length_unit = f"{unit.Prefix}METERS"
+                        else:
+                            # Blender's length_unit enum has no entry for other
+                            # SI prefixes (e.g. DECIMETERS), so fall back to
+                            # adaptive display instead of failing to open.
+                            bpy.context.scene.unit_settings.length_unit = "ADAPTIVE"
                 else:
                     bpy.context.scene.unit_settings.system = "IMPERIAL"
                     name = unit.Name.lower()
@@ -1220,7 +1226,17 @@ class IfcImporter:
                             continue
                     for i in range(len(data)):
                         tool.Array.set_children_lock_state(element, i, True)
-                        tool.Array.constrain_children_to_parent(element)
+                    tool.Array.constrain_children_to_parent(element)
+                    for layer in data:
+                        for child_guid in layer.get("children", ()):
+                            try:
+                                self.file.by_guid(child_guid)
+                            except RuntimeError:
+                                print(
+                                    f"setup_arrays: array parent {element.GlobalId} references missing "
+                                    f"child GUID {child_guid!r}."
+                                )
+                                self.broken_arrays.add(element)
 
     def update_linked_aggregates(self):
         # TODO Remove this after a while. See commit 17d6b8a

src/bonsai/bonsai/bim/module/aggregate/decorator.py

@@ -20,7 +20,6 @@ import blf
 import bpy
 import gpu
 import ifcopenshell.util.element
-from bpy.types import SpaceView3D
 from bpy_extras import view3d_utils
 from gpu_extras.batch import batch_for_shader
 from mathutils import Vector
@@ -28,12 +27,6 @@ from mathutils import Vector
 import bonsai.tool as tool
 
 
-def transparent_color(color, alpha=0.1):
-    color = [i for i in color]
-    color[3] = alpha
-    return color
-
-
 def create_bounding_box(objs):
     # Initialize the bounding box coordinates
     min_x, min_y, min_z = float("inf"), float("inf"), float("inf")
@@ -79,26 +72,8 @@ def create_bounding_box(objs):
     return indices, edges
 
 
-class AggregateDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_aggregate, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
+class AggregateDecorator(tool.Blender.ViewportDecorator):
+    draw_method = "draw_aggregate"
 
     def dotted_line_shader(self):
         vert_out = gpu.types.GPUStageInterfaceInfo("my_interface")
@@ -153,14 +128,6 @@ class AggregateDecorator:
         shader.uniform_float("u_Scale", 25)
         batch.draw(shader)
 
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
-
     def draw_aggregate(self, context):
         props = tool.Aggregate.get_aggregate_props()
         self.addon_prefs = tool.Blender.get_addon_preferences()
@@ -191,12 +158,13 @@ class AggregateDecorator:
                 aggregates.append(obj)
                 continue
 
+            aggregate = None
             aggregates_list = tool.Aggregate.get_aggregates_recursively(element)
             if props.in_aggregate_mode and props.editing_aggregate:
                 index = aggregates_list.index(tool.Ifc.get_entity(props.editing_aggregate))
                 if index > 0:
                     aggregate = aggregates_list[index - 1]
-            else:
+            elif aggregates_list:
                 aggregate = aggregates_list[-1]
             if aggregate:
                 aggregates.append(tool.Ifc.get_object(aggregate))
@@ -225,39 +193,11 @@ class AggregateDecorator:
             self.draw_custom_batch(line, decorator_color_unselected)
 
 
-class AggregateModeDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(
-            SpaceView3D.draw_handler_add(handler.draw_aggregate_name, (context,), "WINDOW", "POST_PIXEL")
-        )
-        cls.handlers.append(
-            SpaceView3D.draw_handler_add(handler.draw_aggregate_empty, (context,), "WINDOW", "POST_VIEW")
-        )
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
+class AggregateModeDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_aggregate_name", "POST_PIXEL"),
+        ("draw_aggregate_empty", "POST_VIEW"),
+    )
 
     def draw_aggregate_name(self, context):
         if context.mode == "EDIT_MESH":

src/bonsai/bonsai/bim/module/boundary/decorator.py

@@ -56,11 +56,6 @@ class BoundaryDecorator:
         unselected_elements_color = self.addon_prefs.decorator_color_unselected
         special_elements_color = self.addon_prefs.decorator_color_special
 
-        def transparent_color(color, alpha=0.1):
-            color = [i for i in color]
-            color[3] = alpha
-            return color
-
         gpu.state.point_size_set(6)
         gpu.state.blend_set("ALPHA")
 
@@ -109,7 +104,11 @@ class BoundaryDecorator:
 
         if unselected_edges:
             self.draw_batch("LINES", unselected_vertices, special_elements_color, unselected_edges)
-            self.draw_batch("TRIS", unselected_vertices, transparent_color(special_elements_color), unselected_tris)
+            self.draw_batch(
+                "TRIS", unselected_vertices, tool.Blender.transparent_color(special_elements_color), unselected_tris
+            )
         if selected_edges:
             self.draw_batch("LINES", selected_vertices, selected_elements_color, selected_edges)
-            self.draw_batch("TRIS", selected_vertices, transparent_color(selected_elements_color), selected_tris)
+            self.draw_batch(
+                "TRIS", selected_vertices, tool.Blender.transparent_color(selected_elements_color), selected_tris
+            )

src/bonsai/bonsai/bim/module/brick/data.py

@@ -156,16 +156,13 @@ class BrickschemaReferencesData:
         for rel in getattr(tool.Ifc.get_entity(bpy.context.active_object), "HasAssociations", []):
             if rel.is_a("IfcRelAssociatesLibrary"):
                 reference = rel.RelatingLibrary
-                if tool.Ifc.get_schema() == "IFC2X3" and "#" not in reference.ItemReference:
-                    continue
-                if tool.Ifc.get_schema() != "IFC2X3" and "#" not in reference.Identification:
+                identification = tool.Document.get_external_reference_id(reference)
+                if not identification or "#" not in identification:
                     continue
                 results.append(
                     {
                         "id": reference.id(),
-                        "identification": (
-                            reference.ItemReference if tool.Ifc.get_schema() == "IFC2X3" else reference.Identification
-                        ),
+                        "identification": identification,
                         "name": reference.Name or "Unnamed",
                     }
                 )

src/bonsai/bonsai/bim/module/cad/operator.py

@@ -345,9 +345,17 @@ class CadArcFrom3Points(bpy.types.Operator):
 class CadOffset(bpy.types.Operator):
     bl_idname = "bim.cad_offset"
     bl_label = "CAD Offset"
-    bl_description = "Copy selected mesh geometry at provided offset. Mesh copied based on the current viewport angle."
+    bl_description = (
+        "Offset selected mesh geometry at provided distance, based on the current viewport angle. "
+        "Creates a copy by default, or moves the existing edges if Copy is disabled."
+    )
     bl_options = {"REGISTER", "UNDO"}
     distance: bpy.props.FloatProperty(name="Distance", default=0.1, subtype="DISTANCE")
+    copy: bpy.props.BoolProperty(
+        name="Copy",
+        description="Create a new offset copy of the geometry. If disabled, move the existing edges to the offset location",
+        default=True,
+    )
 
     @classmethod
     def poll(cls, context):
@@ -405,6 +413,11 @@ class CadOffset(bpy.types.Operator):
         rotation = Matrix.Rotation(pi / 2, 2, "Z")
         rotation_i = Matrix.Rotation(-pi / 2, 2, "Z")
 
+        # When not copying, the offset positions are gathered here and applied to
+        # the existing verts only after all loops are processed, so that the
+        # original coordinates are still available while computing offsets.
+        moved_verts = []
+
         # Create loops from edges
         loop_edges = set(edges)
         loops = []
@@ -517,12 +530,15 @@ class CadOffset(bpy.types.Operator):
                     offset_length = self.distance / sqrt((1 + normals[0].dot(normals[1])) / 2)
                     offset = mw.inverted().to_quaternion() @ (wp.to_quaternion() @ (new_normal * offset_length).to_3d())
                     new_vert = v1.co + offset
-                    new_verts.append(bm.verts.new(new_vert))
                 else:
                     normal = (normals[0] * self.distance).to_3d()
                     offset = mw.inverted().to_quaternion() @ (wp.to_quaternion() @ normal)
                     new_vert = v1.co + offset
+
+                if self.copy:
                     new_verts.append(bm.verts.new(new_vert))
+                else:
+                    moved_verts.append((v1, new_vert))
 
                 processed_verts.add(v1.index)
 
@@ -531,9 +547,14 @@ class CadOffset(bpy.types.Operator):
 
                 v1 = v2
 
-            [bm.edges.new((new_verts[i], new_verts[i + 1])) for i in range(len(new_verts) - 1)]
-            if is_closed:
-                bm.edges.new((new_verts[len(new_verts) - 1], new_verts[0]))
+            if self.copy:
+                [bm.edges.new((new_verts[i], new_verts[i + 1])) for i in range(len(new_verts) - 1)]
+                if is_closed:
+                    bm.edges.new((new_verts[len(new_verts) - 1], new_verts[0]))
+
+        # Move the existing edges to the offset location.
+        for vert, new_co in moved_verts:
+            vert.co = new_co
 
         bm.verts.index_update()
         bm.edges.index_update()

src/bonsai/bonsai/bim/module/cad/prop.py

@@ -27,6 +27,11 @@ class BIMCadProperties(PropertyGroup):
     resolution: bpy.props.IntProperty(name="Arc Resolution", min=1, default=1)
     radius: bpy.props.FloatProperty(name="Radius", default=0.1, subtype="DISTANCE")
     distance: bpy.props.FloatProperty(name="Distance", default=0.1, subtype="DISTANCE")
+    copy: bpy.props.BoolProperty(
+        name="Copy",
+        description="Create a new offset copy of the geometry. If disabled, move the existing edges to the offset location",
+        default=True,
+    )
     x: bpy.props.FloatProperty(name="X", default=0.2, subtype="DISTANCE")
     y: bpy.props.FloatProperty(name="Y", default=0.1, subtype="DISTANCE")
     gable_roof_edge_angle: bpy.props.FloatProperty(
@@ -37,6 +42,7 @@ class BIMCadProperties(PropertyGroup):
         resolution: int
         radius: float
         distance: float
+        copy: bool
         x: float
         y: float
         gable_roof_edge_angle: float

src/bonsai/bonsai/bim/module/cad/workspace.py

@@ -256,6 +256,8 @@ class CadHotkey(bpy.types.Operator):
         elif self.hotkey == "S_O":
             row = self.layout.row()
             row.prop(props, "distance")
+            row = self.layout.row()
+            row.prop(props, "copy")
 
         elif self.hotkey == "S_R":
             if tool.Geometry.is_profile_object_active():
@@ -291,7 +293,7 @@ class CadHotkey(bpy.types.Operator):
             bpy.ops.bim.cad_fillet(resolution=self.props.resolution, radius=self.props.radius)
 
     def hotkey_S_O(self):
-        bpy.ops.bim.cad_offset(distance=self.props.distance)
+        bpy.ops.bim.cad_offset(distance=self.props.distance, copy=self.props.copy)
 
     def hotkey_S_Q(self):
         obj = bpy.context.active_object

src/bonsai/bonsai/bim/module/clash/decorator.py

@@ -18,43 +18,17 @@
 
 import blf
 import gpu
-from bpy.types import SpaceView3D
 from bpy_extras.view3d_utils import location_3d_to_region_2d
-from gpu_extras.batch import batch_for_shader
 from mathutils import Vector
 
 import bonsai.tool as tool
 
 
-class ClashDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_text, (context,), "WINDOW", "POST_PIXEL"))
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_geometry, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
+class ClashDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_text", "POST_PIXEL"),
+        ("draw_geometry", "POST_VIEW"),
+    )
 
     def draw_text(self, context):
         self.addon_prefs = tool.Blender.get_addon_preferences()

src/bonsai/bonsai/bim/module/clip_box/__init__.py

@@ -0,0 +1,130 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+import bpy
+from bpy.app.handlers import persistent
+
+import bonsai.tool as tool
+
+from . import face_quad, gizmos, operator, prop, ui
+
+classes = (
+    operator.BIM_OT_add_clip_box,
+    operator.BIM_OT_add_clip_box_for_source,
+    operator.BIM_OT_align_view_to_clip_face,
+    operator.BIM_OT_duplicate_clip_box,
+    operator.BIM_OT_remove_clip_box,
+    operator.BIM_OT_set_active_clip_box,
+    operator.BIM_OT_toggle_clip_box_enabled,
+    prop.BIMClipBoxProperties,
+    prop.BIMSceneClipBoxProperties,
+    face_quad.BIM_GT_box_face_quad,
+    face_quad.BIM_GT_box_face_outline,
+    gizmos.OBJECT_GGT_bim_clip_box,
+    ui.BIM_MT_clip_box_add_for_source,
+    ui.BIM_MT_clip_box_info,
+    ui.BIM_MT_clip_box_settings,
+    ui.BIM_UL_clip_box,
+    ui.BIM_PT_clip_box,
+)
+
+
+@persistent
+def _on_depsgraph_update(scene, depsgraph):
+    tool.ClipBox.on_depsgraph_update(scene, depsgraph)
+    tool.ClipBox.on_depsgraph_update_caps(scene, depsgraph)
+
+
+@persistent
+def _on_load_pre(filepath):
+    # Tear down any in-flight clip-box timers before Blender frees the
+    # WM / screens / areas / regions for the loading file. A refresh timer
+    # that survives the teardown fires against the new file's freshly-
+    # allocated regions before their GPU state is wired, CTD-ing inside
+    # GPU_matrix_ortho_set. The gate also blocks the depsgraph IFC-reload
+    # branch and is held closed until on_pre_view fires for the first time
+    # on the new file (first paint = GPU contexts wired).
+    tool.ClipBox._file_loading = True
+    tool.ClipBox._post_load_paint_pending = True
+    tool.ClipBox._cancel_pending_refresh()
+    tool.ClipBox._cancel_pending_cap_rebuild()
+
+
+@persistent
+def _on_load_post(filepath):
+    # The _file_loading gate is NOT cleared here: load_post fires before
+    # the new file's first paint, so GPU contexts may still be uninitialised.
+    # on_pre_view consumes _post_load_paint_pending to open the gate at the
+    # safe moment and kick the post-load re-arm.
+    # Restore the per-scene clip-box list from the project's BBIM_ClipBoxes
+    # pset. Runs after the standard load_post that creates Blender objects.
+    tool.ClipBox._last_seen_object_matrices.clear()
+    tool.ClipBox.load_from_project_pset()
+
+
+_draw_handler_pre = None
+_draw_handler_post = None
+
+
+def register():
+    global _draw_handler_pre, _draw_handler_post
+    bpy.types.Object.BIMClipBoxProperties = bpy.props.PointerProperty(type=prop.BIMClipBoxProperties)
+    bpy.types.Scene.BIMSceneClipBoxProperties = bpy.props.PointerProperty(type=prop.BIMSceneClipBoxProperties)
+    tool.ClipBox.reset_ownership()
+    if _on_depsgraph_update not in bpy.app.handlers.depsgraph_update_post:
+        bpy.app.handlers.depsgraph_update_post.append(_on_depsgraph_update)
+    if _on_load_pre not in bpy.app.handlers.load_pre:
+        bpy.app.handlers.load_pre.append(_on_load_pre)
+    if _on_load_post not in bpy.app.handlers.load_post:
+        bpy.app.handlers.load_post.append(_on_load_post)
+    if _draw_handler_pre is None:
+        _draw_handler_pre = bpy.types.SpaceView3D.draw_handler_add(tool.ClipBox.on_pre_view, (), "WINDOW", "PRE_VIEW")
+    if _draw_handler_post is None:
+        _draw_handler_post = bpy.types.SpaceView3D.draw_handler_add(
+            tool.ClipBox.on_post_view_caps, (), "WINDOW", "POST_VIEW"
+        )
+
+
+def unregister():
+    global _draw_handler_pre, _draw_handler_post
+    if _draw_handler_post is not None:
+        try:
+            bpy.types.SpaceView3D.draw_handler_remove(_draw_handler_post, "WINDOW")
+        except ValueError:
+            pass
+        _draw_handler_post = None
+    if _draw_handler_pre is not None:
+        try:
+            bpy.types.SpaceView3D.draw_handler_remove(_draw_handler_pre, "WINDOW")
+        except ValueError:
+            pass
+        _draw_handler_pre = None
+    if _on_load_post in bpy.app.handlers.load_post:
+        bpy.app.handlers.load_post.remove(_on_load_post)
+    if _on_load_pre in bpy.app.handlers.load_pre:
+        bpy.app.handlers.load_pre.remove(_on_load_pre)
+    if _on_depsgraph_update in bpy.app.handlers.depsgraph_update_post:
+        bpy.app.handlers.depsgraph_update_post.remove(_on_depsgraph_update)
+    tool.ClipBox._cancel_pending_refresh()
+    tool.ClipBox._cancel_pending_cap_rebuild()
+    tool.ClipBox._last_seen_object_matrices.clear()
+    tool.ClipBox.clear_clip_planes()
+    del bpy.types.Object.BIMClipBoxProperties
+    del bpy.types.Scene.BIMSceneClipBoxProperties

src/bonsai/bonsai/bim/module/clip_box/data.py

@@ -0,0 +1,212 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""EnumProperty ``items=`` callbacks for the source-based clip-box picker.
+
+Each callback returns ``[(id_str, label, description)]`` where ``id_str`` is
+an IFC entity id stringified for entity-driven kinds, an IFC class name for
+``CLASS``, or a fixed status name for ``STATUS``. The clip-box operator
+turns the picked id into a ``matrix_world`` via the source-preset helper.
+"""
+
+from __future__ import annotations
+
+import bonsai.tool as tool
+
+EnumItems = list[tuple[str, str, str]]
+
+# Module-level cache. Blender's EnumProperty stores raw char pointers from the
+# tuples a callback returns, so the Python strings must outlive the draw call.
+# Stashing the latest result per kind keeps them alive across callback firings.
+_items_cache: dict[str, EnumItems] = {}
+
+# Sentinel id used for the "no options available" placeholder. The operator
+# treats this as an invalid pick and surfaces an ERROR.
+NO_OPTIONS_ID = "__none__"
+
+
+def _cache(kind: str, items: EnumItems) -> EnumItems:
+    _items_cache[kind] = items
+    return items
+
+
+def _no_options(label: str) -> EnumItems:
+    # Blender refuses to draw an EnumProperty with zero entries — show a
+    # placeholder so the dialog renders and the user sees the empty state.
+    return [(NO_OPTIONS_ID, label, "")]
+
+
+def _label(entity, ifc_class: str | None = None) -> str:
+    name = (getattr(entity, "Name", None) or "Unnamed").strip() or "Unnamed"
+    return f"{ifc_class}: {name}" if ifc_class else name
+
+
+def _build_items(kind: str, empty_label: str, build_fn) -> EnumItems:
+    """Shared shape for the IFC-driven enum callbacks.
+
+    Returns the no-IFC placeholder if no file is loaded, then runs
+    ``build_fn(ifc_file)``, sorts the result alphabetically by label, and
+    returns the empty-result placeholder if nothing matched. The output is
+    always routed through the module cache.
+    """
+    ifc = tool.Ifc.get()
+    if ifc is None:
+        return _cache(kind, _no_options("No IFC loaded"))
+    items = build_fn(ifc)
+    items.sort(key=lambda t: t[1].lower())
+    if not items:
+        return _cache(kind, _no_options(empty_label))
+    return _cache(kind, items)
+
+
+# Top-down spatial hierarchy so the picker reads in the order an architect
+# already thinks in, rather than a flat alphabetical mix. IfcSpace is excluded
+# — spaces are typically empty volumes used for room metadata, so clipping to
+# one rarely matches the user intent of "show me what's in this container".
+SPATIAL_CLASSES: tuple[str, ...] = (
+    "IfcProject",
+    "IfcSite",
+    "IfcBuilding",
+    "IfcBuildingStorey",
+)
+
+
+def spatial_items(self, context) -> EnumItems:
+    # Special-case: per-class sort within the hierarchy order rather than a
+    # flat alphabetical sort, so the dropdown reads project → site → building.
+    ifc = tool.Ifc.get()
+    if ifc is None:
+        return _cache("SPATIAL", _no_options("No IFC loaded"))
+    items: EnumItems = []
+    for ifc_class in SPATIAL_CLASSES:
+        try:
+            entities = ifc.by_type(ifc_class, include_subtypes=False)
+        except RuntimeError:
+            continue
+        for entity in sorted(entities, key=lambda e: (e.Name or "").lower()):
+            items.append((str(entity.id()), _label(entity, ifc_class), ""))
+    if not items:
+        return _cache("SPATIAL", _no_options("No spatial containers"))
+    return _cache("SPATIAL", items)
+
+
+def class_items(self, context) -> EnumItems:
+    # Special-case: the picker value IS the IFC class name, not an entity id,
+    # so the build shape differs from the other entity-driven callbacks.
+    ifc = tool.Ifc.get()
+    if ifc is None:
+        return _cache("CLASS", _no_options("No IFC loaded"))
+    # List only IFC classes ACTUALLY present in the file (not the whole
+    # schema), so the user picks from classes that can produce a non-empty
+    # clip volume. ``e.is_a()`` returns the most specific class per element.
+    present = sorted({e.is_a() for e in ifc.by_type("IfcProduct")})
+    if not present:
+        return _cache("CLASS", _no_options("No products"))
+    return _cache("CLASS", [(cls, cls, "") for cls in present])
+
+
+def type_items(self, context) -> EnumItems:
+    return _build_items(
+        "TYPE",
+        "No types defined",
+        lambda ifc: [(str(e.id()), _label(e, e.is_a()), "") for e in ifc.by_type("IfcTypeProduct")],
+    )
+
+
+def material_items(self, context) -> EnumItems:
+    return _build_items(
+        "MATERIAL",
+        "No materials defined",
+        lambda ifc: [(str(e.id()), _label(e), "") for e in ifc.by_type("IfcMaterial")],
+    )
+
+
+def profile_items(self, context) -> EnumItems:
+    # ProfileName is optional. Skip unnamed profiles — they can't be
+    # meaningfully picked from a flat list.
+    return _build_items(
+        "PROFILE",
+        "No named profiles",
+        lambda ifc: [
+            (str(e.id()), f"{e.is_a()}: {e.ProfileName}", "")
+            for e in ifc.by_type("IfcProfileDef")
+            if getattr(e, "ProfileName", None)
+        ],
+    )
+
+
+def drawing_items(self, context) -> EnumItems:
+    return _build_items(
+        "DRAWING",
+        "No drawings defined",
+        lambda ifc: [(str(e.id()), _label(e), "") for e in ifc.by_type("IfcAnnotation") if e.ObjectType == "DRAWING"],
+    )
+
+
+# Display labels for each status value. The id strings on the left are the
+# canonical Pset_*Common.Status enum values accepted by Bonsai's status query.
+STATUS_LABELS: tuple[tuple[str, str], ...] = (
+    ("No Status", "No Status"),
+    ("NEW", "New"),
+    ("EXISTING", "Existing"),
+    ("DEMOLISH", "Demolish"),
+    ("TEMPORARY", "Temporary"),
+    ("OTHER", "Other"),
+    ("NOTKNOWN", "Not Known"),
+    ("UNSET", "Unset"),
+)
+
+
+def status_items(self, context) -> EnumItems:
+    # Fixed enum; no IFC needed. Still routed through the cache to share the
+    # same string-lifetime guarantee as the other callbacks.
+    return _cache("STATUS", [(value, label, "") for value, label in STATUS_LABELS])
+
+
+def system_items(self, context) -> EnumItems:
+    # IfcStructuralAnalysisModel is a structural-grouping container, not a
+    # distribution system — excluded to match Bonsai's other system pickers.
+    return _build_items(
+        "SYSTEM",
+        "No systems defined",
+        lambda ifc: [
+            (str(e.id()), _label(e, e.is_a()), "")
+            for e in ifc.by_type("IfcSystem")
+            if not e.is_a("IfcStructuralAnalysisModel")
+        ],
+    )
+
+
+def group_items(self, context) -> EnumItems:
+    # include_subtypes=False so IfcSystem and IfcZone instances don't appear
+    # under Group as well — those get their own picker entries.
+    return _build_items(
+        "GROUP",
+        "No groups defined",
+        lambda ifc: [(str(e.id()), _label(e), "") for e in ifc.by_type("IfcGroup", include_subtypes=False)],
+    )
+
+
+def zone_items(self, context) -> EnumItems:
+    return _build_items(
+        "ZONE",
+        "No zones defined",
+        lambda ifc: [(str(e.id()), _label(e), "") for e in ifc.by_type("IfcZone")],
+    )

src/bonsai/bonsai/bim/module/clip_box/face_quad.py

@@ -0,0 +1,879 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Generic face-quad resize gizmos for any axis-aligned local box.
+
+This module contains the box-agnostic core of the interactive
+face-resize gizmos: two Gizmo classes (a near-invisible click target
+welded to each face, and a thin colored edge outline), a per-redraw
+orchestrator that places six of each on a box, and the pure one-sided
+resize arithmetic. None of it knows about IFC, clip boxes, or
+``BIMSceneClipBoxProperties`` — a future camera-view-box adapter can
+reuse the same classes and helpers.
+
+Consumer contract — the adapter group must:
+
+1. Create six ``BIM_GT_box_face_quad`` and six ``BIM_GT_box_face_outline``
+   instances at ``setup()`` time, in :data:`FACE_ROUTES` order, and bind
+   each quad's ``move_get_cb`` / ``move_set_cb`` to closures that read
+   and mutate the box's host (e.g. an Empty's ``location`` / ``scale``).
+2. Call :func:`apply_face_quad_layout` from ``refresh()`` /
+   ``draw_prepare()`` with the box's local-frame ``bmin`` / ``bmax``,
+   the host's ``matrix_world``, the OBB rotation as a 4x4
+   (``Matrix.Identity(4)`` when the rotation rides in ``matrix_world``),
+   and the current ``region`` / ``rv3d``.
+3. Implement ``_lock_for(active_gz)`` / ``_unlock_all()`` on the group
+   for drag mutual exclusion; the quad's ``invoke`` / ``exit`` call them.
+
+The resize arithmetic in :func:`compute_face_resize` is pure: feed it
+the modal scalar plus drag-start snapshots and it returns the host's
+new scale-on-axis and new origin location.
+"""
+
+from __future__ import annotations
+
+import math
+from collections.abc import Sequence
+from typing import Any
+
+import bpy
+from bpy_extras.view3d_utils import location_3d_to_region_2d, region_2d_to_location_3d
+from mathutils import Matrix, Vector
+
+# ---------------------------------------------------------------------------
+# Public iteration order
+# ---------------------------------------------------------------------------
+
+# (axis, is_max) pairs. The adapter group's ``setup()`` MUST create its
+# six face-quad gizmos in this order so positional indexing into the
+# layout helper stays correct.
+FACE_ROUTES: tuple[tuple[int, bool], ...] = (
+    (0, False),
+    (0, True),
+    (1, False),
+    (1, True),
+    (2, False),
+    (2, True),
+)
+
+
+# ---------------------------------------------------------------------------
+# Public visual constants (adapter reads these in setup())
+# ---------------------------------------------------------------------------
+
+# Standard XYZ axis colors (Blender convention).
+AXIS_COLOR: dict[int, tuple[float, float, float]] = {
+    0: (1.0, 0.2, 0.2),
+    1: (0.2, 1.0, 0.2),
+    2: (0.2, 0.4, 1.0),
+}
+
+# Documented "selectable but unpainted" trick: the GPU still writes the
+# selection buffer at this alpha so clicks register, but no visible
+# pixels are produced.
+FACE_QUAD_ALPHA: float = 0.001
+
+# Very faint hover tint — just enough to confirm "you're aiming at this
+# face" without painting visibly over geometry behind it.
+FACE_QUAD_ALPHA_HIGHLIGHT: float = 0.04
+
+# Setup-time default for ``select_bias``; the layout helper overwrites
+# it per frame to the front-facing or halo value below. Kept below the
+# canonical arrow bias so a bailed frame can't let a front quad steal
+# clicks meant for a hidden control.
+FACE_QUAD_SELECT_BIAS: float = 0.5
+
+
+# ---------------------------------------------------------------------------
+# Internal constants
+# ---------------------------------------------------------------------------
+
+# Unit quad in the local XY plane spanning [-0.5, 0.5]^2 at z=0. Two
+# CCW triangles viewed from +Z. matrix_basis stretches it onto the
+# face's perpendicular extents.
+_QUAD_TRIS: list[tuple[float, float, float]] = [
+    (-0.5, -0.5, 0.0),
+    (0.5, -0.5, 0.0),
+    (0.5, 0.5, 0.0),
+    (-0.5, -0.5, 0.0),
+    (0.5, 0.5, 0.0),
+    (-0.5, 0.5, 0.0),
+]
+
+# Unit-quad outline as 4 line segments in the local XY plane at z=0.
+_QUAD_OUTLINE_LINES: list[tuple[float, float, float]] = [
+    (-0.5, -0.5, 0.0),
+    (0.5, -0.5, 0.0),
+    (0.5, -0.5, 0.0),
+    (0.5, 0.5, 0.0),
+    (0.5, 0.5, 0.0),
+    (-0.5, 0.5, 0.0),
+    (-0.5, 0.5, 0.0),
+    (-0.5, -0.5, 0.0),
+]
+
+# Degenerate zero-area triangle for hidden back-facing quads with no
+# visible-adjacent neighbours (rare orientation). Blender tolerates
+# this; the gizmo is hidden anyway so nothing renders.
+_EMPTY_TRIS: list[tuple[float, float, float]] = [
+    (0.0, 0.0, 0.0),
+    (0.0, 0.0, 0.0),
+    (0.0, 0.0, 0.0),
+]
+
+# Rotates the gizmo's local +Z onto the outward face normal in the
+# box's local frame. Right-hand rotation around the named axis.
+_AXIS_ORIENT: dict[tuple[int, bool], Matrix] = {
+    (0, False): Matrix.Rotation(-math.pi / 2, 4, "Y"),
+    (0, True): Matrix.Rotation(math.pi / 2, 4, "Y"),
+    (1, False): Matrix.Rotation(math.pi / 2, 4, "X"),
+    (1, True): Matrix.Rotation(-math.pi / 2, 4, "X"),
+    (2, False): Matrix.Rotation(math.pi, 4, "X"),
+    (2, True): Matrix.Identity(4),
+}
+
+# Per-face mapping from face-quad local axes to local box axes for the
+# perpendicular-extent scale. ``(w_axis, h_axis)`` — the box-local axis
+# indices the quad's local X and Y span after the orientation rotation.
+_QUAD_PERP_AXES: dict[tuple[int, bool], tuple[int, int]] = {
+    (0, False): (2, 1),
+    (0, True): (2, 1),
+    (1, False): (0, 2),
+    (1, True): (0, 2),
+    (2, False): (0, 1),
+    (2, True): (0, 1),
+}
+
+# Front-facing quad sits ABOVE the halo strips so the cursor on the
+# visible face area always grabs the visible face, never accidentally
+# routes to a back-face halo strip in an adjacent screen region.
+_FACE_QUAD_FRONT_FACING_SELECT_BIAS: float = 1.5
+_FACE_QUAD_HALO_FRAME_SELECT_BIAS: float = 1.0
+
+# Target halo-strip thickness in screen pixels. The world-space margin
+# is recomputed per frame so the rim stays a roughly constant on-screen
+# size regardless of viewport zoom.
+_FACE_QUAD_HALO_TARGET_PIXELS: float = 20.0
+
+# Minimum world half-extent a face resize may shrink to. Stops a drag
+# from collapsing the host to zero or negative scale.
+_MIN_HALF_EXTENT: float = 1e-4
+
+
+# ---------------------------------------------------------------------------
+# Pure predicates (testable without Blender)
+# ---------------------------------------------------------------------------
+
+Vec3 = tuple[float, float, float]
+
+
+def face_outward_axis_local(axis: int, is_max: bool) -> Vec3:
+    """Un-rotated outward face normal in the box's local AABB coords.
+
+    For ``(axis=0, is_max=True)`` returns ``(+1, 0, 0)``; for the −X
+    face ``(-1, 0, 0)``; etc. The rotated world normal is obtained by
+    applying the host's rotation and the OBB rotation:
+    ``mw_rot @ cage_rotation @ this``.
+    """
+    sign = 1.0 if is_max else -1.0
+    out = [0.0, 0.0, 0.0]
+    out[axis] = sign
+    return (out[0], out[1], out[2])
+
+
+def front_facing_face_mask(
+    face_normals_world: Sequence[Vec3],
+    view_dir_world: Vec3,
+    eps: float = 1e-6,
+) -> tuple[bool, ...]:
+    """Which of the 6 box faces point toward the camera.
+
+    A face is front-facing iff its outward normal points AGAINST the
+    view direction (``dot(normal, view_dir) < -eps``). The ``-eps``
+    margin prevents flicker at grazing angles.
+
+    ``face_normals_world`` must be in :data:`FACE_ROUTES` order; returns
+    a 6-tuple of bool parallel to that order.
+    """
+    if len(face_normals_world) != 6:
+        msg = f"expected 6 face normals, got {len(face_normals_world)}"
+        raise ValueError(msg)
+    vx, vy, vz = view_dir_world
+    return tuple((n[0] * vx + n[1] * vy + n[2] * vz) < -eps for n in face_normals_world)
+
+
+def view_axis_parallel_face_mask(
+    face_normals_world: Sequence[Vec3],
+    view_dir_world: Vec3,
+    threshold: float = 0.95,
+) -> tuple[bool, ...]:
+    """Which faces have normals (anti-)parallel to the view direction.
+
+    True iff ``abs(dot(normal, view_dir)) >= threshold`` — i.e. the
+    face is nearly perpendicular to the screen plane. Provided as a
+    pure predicate for callers that want to detect degenerate-drag
+    conditions; the layout helper itself no longer gates on it.
+    """
+    if len(face_normals_world) != 6:
+        msg = f"expected 6 face normals, got {len(face_normals_world)}"
+        raise ValueError(msg)
+    vx, vy, vz = view_dir_world
+    return tuple(abs(n[0] * vx + n[1] * vy + n[2] * vz) >= threshold for n in face_normals_world)
+
+
+# ---------------------------------------------------------------------------
+# Pure resize arithmetic
+# ---------------------------------------------------------------------------
+
+
+def compute_face_resize(
+    *,
+    value: float,
+    init_world_half: float,
+    init_location: tuple[float, float, float],
+    world_axis: tuple[float, float, float],
+    display_size: float,
+) -> tuple[float, tuple[float, float, float]]:
+    """Pure one-sided face-resize arithmetic.
+
+    Returns ``(new_scale_axis, new_location)`` — the host's new scale
+    on the dragged axis and its new world origin — such that the
+    dragged face moves by the modal's outward delta while the OPPOSITE
+    face stays put.
+
+    ``value`` is ``init + delta``, where ``init`` is the unsigned
+    drag-start world half-extent and ``delta`` is the cursor projection
+    onto the face's OUTWARD world normal. Realized half-extent is
+    clamped to a small floor; the location shift uses the realized
+    (post-clamp) delta so the opposite face stays fixed even at the
+    clamp.
+    """
+    face_delta = value - init_world_half
+    new_world_half = init_world_half + 0.5 * face_delta
+    if new_world_half < _MIN_HALF_EXTENT:
+        new_world_half = _MIN_HALF_EXTENT
+    realized_delta = 2.0 * (new_world_half - init_world_half)
+
+    ds = display_size if display_size != 0.0 else 1.0
+    new_scale_axis = new_world_half / ds
+    shift = 0.5 * realized_delta
+    new_location = (
+        init_location[0] + shift * world_axis[0],
+        init_location[1] + shift * world_axis[1],
+        init_location[2] + shift * world_axis[2],
+    )
+    return new_scale_axis, new_location
+
+
+# ---------------------------------------------------------------------------
+# Internal geometry helpers
+# ---------------------------------------------------------------------------
+
+
+def _compute_face_quad_scale(bmin: Any, bmax: Any, axis: int, is_max: bool) -> tuple[float, float]:
+    """Return ``(w, h)`` for the face quad's scale matrix."""
+    w_axis, h_axis = _QUAD_PERP_AXES[(axis, is_max)]
+    w = float(bmax[w_axis] - bmin[w_axis])
+    h = float(bmax[h_axis] - bmin[h_axis])
+    return w, h
+
+
+def _shared_edge_corner_keys(
+    axis_a: int, is_max_a: bool, axis_b: int, is_max_b: bool
+) -> tuple[tuple[int, int, int], tuple[int, int, int]] | None:
+    """Return the 2 corner-bit triples shared by two adjacent faces.
+
+    Corner keys are 3-tuples of bits (0 = bmin, 1 = bmax). The two
+    returned corners are ordered with the free-axis bit ascending.
+    """
+    if axis_a == axis_b:
+        return None
+    free_axis = 3 - axis_a - axis_b
+    bit_a = 1 if is_max_a else 0
+    bit_b = 1 if is_max_b else 0
+    corner_lo = [0, 0, 0]
+    corner_hi = [0, 0, 0]
+    corner_lo[axis_a] = bit_a
+    corner_hi[axis_a] = bit_a
+    corner_lo[axis_b] = bit_b
+    corner_hi[axis_b] = bit_b
+    corner_lo[free_axis] = 0
+    corner_hi[free_axis] = 1
+    return (
+        (corner_lo[0], corner_lo[1], corner_lo[2]),
+        (corner_hi[0], corner_hi[1], corner_hi[2]),
+    )
+
+
+def _face_corner_keys(axis: int, is_max: bool) -> tuple[
+    tuple[int, int, int],
+    tuple[int, int, int],
+    tuple[int, int, int],
+    tuple[int, int, int],
+]:
+    """Return the 4 corner-bit triples of a face in CCW order.
+
+    Triangulation as ``[(0,1,2), (0,2,3)]`` covers the whole face with
+    two non-overlapping triangles.
+    """
+    fixed_bit = 1 if is_max else 0
+    free_axes = [a for a in (0, 1, 2) if a != axis]
+    fa0, fa1 = free_axes
+    corners = []
+    for ka, kb in ((0, 0), (1, 0), (1, 1), (0, 1)):
+        key = [0, 0, 0]
+        key[axis] = fixed_bit
+        key[fa0] = ka
+        key[fa1] = kb
+        corners.append((key[0], key[1], key[2]))
+    return (corners[0], corners[1], corners[2], corners[3])
+
+
+def _build_strip_tris_relative(
+    edge_p0_local: tuple[float, float, float],
+    edge_p1_local: tuple[float, float, float],
+    extrusion_local: tuple[float, float, float],
+) -> list[tuple[float, float, float]]:
+    """Build two CCW triangles (6 vertices) for a thin halo strip.
+
+    All inputs are in coords relative to the gizmo's ``matrix_basis``
+    anchor. The strip runs along ``[edge_p0_local, edge_p1_local]`` and
+    extrudes by ``extrusion_local`` perpendicular to the edge.
+    """
+    p0x, p0y, p0z = edge_p0_local
+    p1x, p1y, p1z = edge_p1_local
+    ex, ey, ez = extrusion_local
+    p0e = (p0x + ex, p0y + ey, p0z + ez)
+    p1e = (p1x + ex, p1y + ey, p1z + ez)
+    return [
+        (p0x, p0y, p0z),
+        p0e,
+        p1e,
+        (p0x, p0y, p0z),
+        p1e,
+        (p1x, p1y, p1z),
+    ]
+
+
+def _strips_geometry_changed(quad_gz, face_quad_local, all_tris) -> bool:
+    """True if the back-face quad's geometry differs from the cached upload.
+
+    Pure orbit/pan doesn't change either the box pose or the cage
+    rotation, so the computed strip vertices are byte-identical to the
+    previous frame's. Hitting the cache lets the back-facing branch
+    skip ``new_custom_shape`` and the GPU upload.
+    """
+    cached = getattr(quad_gz, "_strips_cache_key", None)
+    last_state = getattr(quad_gz, "_last_geometry_state", None)
+    key = (face_quad_local, all_tris)
+    if cached is None or last_state != "strips" or cached != key:
+        quad_gz._strips_cache_key = key
+        quad_gz._last_geometry_state = "strips"
+        return True
+    return False
+
+
+def _compute_face_basis(
+    mw: Any,
+    mw_rot: Any,
+    cage_rotation: Any,
+    pivot_local: Any,
+    face_local: Any,
+    orient: Any,
+) -> tuple[Any, Any]:
+    """World-space (translation, outward-normal-direction) for one face."""
+    rotated_face_local = cage_rotation.to_3x3() @ (face_local - pivot_local) + pivot_local
+    face_world = mw @ rotated_face_local
+    world_axis = (mw_rot @ cage_rotation.to_3x3() @ (orient.to_3x3() @ Vector((0.0, 0.0, 1.0)))).normalized()
+    return face_world, world_axis
+
+
+def _compose_face_matrix_basis(
+    face_world: Any,
+    mw_rot_scale: Any,
+    cage_rotation: Any,
+    orient: Any,
+    w: float,
+    h: float,
+) -> Any:
+    """Compose the 5-term ``matrix_basis`` for a face-plane gizmo.
+
+    Returns ``Translation @ mw_rot_scale @ cage_rotation @ orient @
+    Diagonal((w, h, 1, 1))`` — maps a unit-square local quad onto the
+    world-space face rectangle, including the host's scale.
+    """
+    quad_scale = Matrix.Diagonal((w, h, 1.0, 1.0))
+    return Matrix.Translation(face_world) @ mw_rot_scale.to_4x4() @ cage_rotation @ orient @ quad_scale
+
+
+def _compute_box_corners_world(
+    bmin: Any,
+    bmax: Any,
+    pivot_local: Any,
+    cage_rotation_3x3: Any,
+    mw: Any,
+) -> dict[tuple[int, int, int], Any]:
+    """Return the 8 OBB corners in world space, keyed by bit-triple."""
+    corners: dict[tuple[int, int, int], Any] = {}
+    for ix in (0, 1):
+        for iy in (0, 1):
+            for iz in (0, 1):
+                local = Vector(
+                    (
+                        float(bmax.x if ix else bmin.x),
+                        float(bmax.y if iy else bmin.y),
+                        float(bmax.z if iz else bmin.z),
+                    )
+                )
+                rotated = cage_rotation_3x3 @ (local - pivot_local) + pivot_local
+                corners[(ix, iy, iz)] = mw @ rotated
+    return corners
+
+
+def _abs_scale_matrix(mw: Any) -> Any:
+    """Return a copy of ``mw`` with all scale components ``abs()``-ed.
+
+    Without this, a negative-scale host produces a visible/clickable
+    face inversion: ``mw @ local_vec`` flips the +axis face onto the
+    -axis world side, while the rotation-only normal stays pointing
+    in the +axis direction — so the gizmo for "the +X face" sits at
+    world -X but reports its outward normal as +X.
+    """
+    loc, rot, scale = mw.decompose()
+    abs_scale = Vector((abs(scale.x), abs(scale.y), abs(scale.z)))
+    return Matrix.LocRotScale(loc, rot, abs_scale)
+
+
+def _world_radius_to_screen_pixels(
+    region: Any,
+    rv3d: Any,
+    center_world: Vector,
+    world_radius: float,
+    *,
+    min_pixels: float = 0.0,
+) -> float:
+    """Return the on-screen pixel radius of a world-space circle.
+
+    Projects ``center_world`` and a sample point offset by
+    ``world_radius`` along the camera's view-aligned right axis to
+    region pixels, and returns the screen-pixel distance between them.
+    Falls back to ``min_pixels`` if either projection fails.
+    """
+    try:
+        view_inv = rv3d.view_matrix.inverted()
+        right = Vector((view_inv[0][0], view_inv[0][1], view_inv[0][2])).normalized()
+    except (AttributeError, ValueError):
+        right = Vector((1.0, 0.0, 0.0))
+    sample_world = center_world + right * world_radius
+    return _world_segment_to_screen_pixels(region, rv3d, center_world, sample_world, min_pixels=min_pixels)
+
+
+def _world_segment_to_screen_pixels(
+    region: Any,
+    rv3d: Any,
+    p0_world: Vector,
+    p1_world: Vector,
+    *,
+    min_pixels: float = 0.0,
+) -> float:
+    """Return the on-screen pixel length of an arbitrary world segment.
+
+    Unlike :func:`_world_radius_to_screen_pixels`, this measures the
+    ACTUAL projected length of the segment — foreshortening included.
+    Use this when the segment direction is known to be oblique to the
+    screen plane (e.g. a back face's outward normal): a perpendicular
+    radius measurement overestimates the on-screen length, leaving
+    halo strips visually narrower than the requested pixel target.
+    """
+    p0 = location_3d_to_region_2d(region, rv3d, p0_world)
+    p1 = location_3d_to_region_2d(region, rv3d, p1_world)
+    if not p0 or not p1:
+        return min_pixels
+    dx = float(p1[0]) - float(p0[0])
+    dy = float(p1[1]) - float(p0[1])
+    return max(min_pixels, (dx * dx + dy * dy) ** 0.5)
+
+
+# ---------------------------------------------------------------------------
+# Gizmo classes
+# ---------------------------------------------------------------------------
+
+
+class BIM_GT_box_face_quad(bpy.types.Gizmo):  # noqa: N801 — Blender bl_idname convention
+    """Near-invisible face-quad click target with drag-to-resize modal.
+
+    Geometry: a unit quad in the local XY plane at z=0. The adapter
+    group's layout helper rotates and scales it onto the face plane;
+    the quad is welded to the world face (``use_draw_scale = False``).
+    """
+
+    bl_idname = "BIM_GT_box_face_quad"
+    bl_target_properties = ({"id": "offset", "type": "FLOAT", "array_length": 1},)
+
+    __slots__ = (
+        "custom_shape",
+        "custom_shape_select",
+        "init_value",
+        "move_get_cb",
+        "move_set_cb",
+        "axis",
+        "start_location",
+        "depth_point",
+        "callback",
+        "ctrl_click_cb",
+        "_group",
+        "_face_axis",
+        "is_max",
+        "_drag_snapshot",
+        "_last_geometry_state",
+        "_strips_cache_key",
+    )
+
+    def draw(self, context: Any) -> None:
+        self.draw_custom_shape(self.custom_shape)
+
+    def draw_select(self, context: Any, select_id: int) -> None:
+        # Back-facing quads bind ``custom_shape_select`` to the halo-strip
+        # TRIS so clicks OUTSIDE the box silhouette catch the back face.
+        # Front-facing quads leave it None and reuse ``custom_shape``.
+        shape = getattr(self, "custom_shape_select", None) or self.custom_shape
+        self.draw_custom_shape(shape, select_id=select_id)
+
+    def setup(self) -> None:
+        if not hasattr(self, "custom_shape_"):
+            self.custom_shape = self.new_custom_shape("TRIS", _QUAD_TRIS)
+        self.custom_shape_select = None
+        # Quad welded to world geometry — clicks must align with the
+        # visible face, not a screen-size widget. Disables Blender's
+        # per-frame pixel-constant autoscale.
+        self.use_draw_scale = False
+
+    # ---- modal -------------------------------------------------------------
+
+    def invoke(self, context: Any, event: Any) -> set[str]:
+        # CTRL+click handoff: dispatch a host-defined callback (e.g.
+        # align-view) instead of starting a drag.
+        if event.ctrl and getattr(self, "ctrl_click_cb", None) is not None:
+            self.ctrl_click_cb(context, event)
+            return {"FINISHED"}
+
+        region = context.region
+        rv3d = context.region_data
+        if region is None or rv3d is None:
+            return {"CANCELLED"}
+        self.init_value = self.move_get_cb()
+        # Freeze the projection plane at invoke — projection-plane
+        # drift on tilted axes causes exponential delta runaway.
+        self.depth_point = self.matrix_basis.translation.copy()
+        self.start_location = region_2d_to_location_3d(region, rv3d, (event.mouse_x, event.mouse_y), self.depth_point)
+
+        if getattr(self, "_group", None) is not None:
+            self._group._lock_for(self)
+        return {"RUNNING_MODAL"}
+
+    def exit(self, context: Any, cancel: bool) -> None:
+        try:
+            if context.area:
+                context.area.header_text_set(None)
+            if cancel:
+                self.move_set_cb(self.init_value)
+            if hasattr(self, "callback"):
+                self.callback(self.move_get_cb())
+        finally:
+            self._drag_snapshot = None
+            if getattr(self, "_group", None) is not None:
+                self._group._unlock_all()
+
+    def modal(self, context: Any, event: Any, tweak: set[str]) -> set[str]:
+        if event.type == "ESC":
+            return {"CANCELLED"}
+        region = context.region
+        rv3d = context.region_data
+        if region is None or rv3d is None:
+            return {"CANCELLED"}
+        end_location = region_2d_to_location_3d(region, rv3d, (event.mouse_x, event.mouse_y), self.depth_point)
+        delta = (end_location - self.start_location).dot(self.axis)
+        if "SNAP" in tweak:
+            delta = round(delta, 1)
+        if "PRECISE" in tweak:
+            delta /= 10.0
+        self.move_set_cb(self.init_value + delta)
+        if context.area:
+            context.area.header_text_set(f"Value: {self.move_get_cb():.3f} ({delta:.3f})")
+        return {"RUNNING_MODAL"}
+
+
+class BIM_GT_box_face_outline(bpy.types.Gizmo):  # noqa: N801 — Blender bl_idname convention
+    """Thin non-interactive colored edge outline for one face.
+
+    Drawn as 4 line segments in the face plane. The layout helper
+    toggles its ``alpha`` between near-zero and ``1.0`` based on the
+    sibling face-quad's ``is_highlight`` state — so hovering the quad
+    lights up the matching outline. ``hide_select = True`` keeps the
+    outline out of the GPU selection buffer.
+    """
+
+    bl_idname = "BIM_GT_box_face_outline"
+    bl_target_properties = ()
+
+    __slots__ = (
+        "custom_shape",
+        "_face_axis",
+        "is_max",
+        "_last_outline_state",
+    )
+
+    def draw(self, context: Any) -> None:
+        self.draw_custom_shape(self.custom_shape)
+
+    def draw_select(self, context: Any, select_id: int) -> None:
+        return None
+
+    def setup(self) -> None:
+        if not hasattr(self, "custom_shape_"):
+            self.custom_shape = self.new_custom_shape("LINES", _QUAD_OUTLINE_LINES)
+        self.use_draw_scale = False
+        self.hide_select = True
+        self._last_outline_state = "unit"
+
+
+# ---------------------------------------------------------------------------
+# Per-redraw orchestrator
+# ---------------------------------------------------------------------------
+
+
+def apply_face_quad_layout(
+    *,
+    quad_gizmos,
+    outline_gizmos,
+    bmin: Any,
+    bmax: Any,
+    matrix_world: Any,
+    cage_rotation: Any,
+    region: Any,
+    rv3d: Any,
+    locked: bool,
+) -> None:
+    """Lay out 6 face quads + 6 outlines on the box for this redraw.
+
+    ``quad_gizmos`` / ``outline_gizmos`` are length-6 sequences in
+    :data:`FACE_ROUTES` order. ``bmin`` / ``bmax`` are the box corners
+    in the host's local frame; ``matrix_world`` is the host's world
+    matrix; ``cage_rotation`` is the OBB rotation as a 4x4 (use
+    ``Matrix.Identity(4)`` when rotation rides in ``matrix_world``).
+    ``region`` / ``rv3d`` drive the view-dependent front/back split and
+    the screen-constant halo margin; passing ``rv3d = None`` bails.
+
+    Negative scale on the host is normalized to positive internally so
+    the visible cube and the clickable face gizmos stay aligned —
+    callers don't need to pre-process ``matrix_world``.
+
+    When ``locked`` (a drag is active), ``hide`` / ``select_bias``
+    writes are skipped — the active quad's geometry is still refreshed
+    so it tracks the moving box.
+    """
+    if rv3d is None or getattr(rv3d, "view_rotation", None) is None:
+        return
+    if len(quad_gizmos) != 6 or len(outline_gizmos) != 6:
+        return
+
+    mw = _abs_scale_matrix(matrix_world)
+    mw_rot = mw.to_quaternion().to_matrix()
+    mw_rot_scale = mw.to_3x3()
+    cage_rotation_3x3 = cage_rotation.to_3x3()
+    pivot_local = (bmin + bmax) * 0.5
+    box_center_local = pivot_local
+    face_midpoints_local = {
+        (0, False): Vector((float(bmin.x), box_center_local.y, box_center_local.z)),
+        (0, True): Vector((float(bmax.x), box_center_local.y, box_center_local.z)),
+        (1, False): Vector((box_center_local.x, float(bmin.y), box_center_local.z)),
+        (1, True): Vector((box_center_local.x, float(bmax.y), box_center_local.z)),
+        (2, False): Vector((box_center_local.x, box_center_local.y, float(bmin.z))),
+        (2, True): Vector((box_center_local.x, box_center_local.y, float(bmax.z))),
+    }
+
+    view_dir = (rv3d.view_rotation @ Vector((0.0, 0.0, -1.0))).normalized()
+    view_dir_tuple = (float(view_dir.x), float(view_dir.y), float(view_dir.z))
+    face_normals_world = []
+    for route_axis, route_is_max in FACE_ROUTES:
+        axis_local = Vector(face_outward_axis_local(route_axis, route_is_max))
+        n_world = (mw_rot @ cage_rotation_3x3 @ axis_local).normalized()
+        face_normals_world.append((float(n_world.x), float(n_world.y), float(n_world.z)))
+    front = front_facing_face_mask(tuple(face_normals_world), view_dir_tuple)
+
+    box_center_world = mw @ pivot_local
+    corners_world = _compute_box_corners_world(bmin, bmax, pivot_local, cage_rotation_3x3, mw)
+    route_to_index = {route: i for i, route in enumerate(FACE_ROUTES)}
+
+    for i, route in enumerate(FACE_ROUTES):
+        quad_gz = quad_gizmos[i]
+        is_front = front[i]
+        axis_b, is_max_b = route
+
+        # Place the colored OUTLINE on every face using the same composed
+        # face matrix the front-facing solid quad uses. Hidden/shown via
+        # alpha at the end of the pass.
+        outline_orient = _AXIS_ORIENT[route]
+        outline_face_world, _outline_axis = _compute_face_basis(
+            mw,
+            mw_rot,
+            cage_rotation,
+            pivot_local,
+            face_midpoints_local[route],
+            outline_orient,
+        )
+        ow, oh = _compute_face_quad_scale(bmin, bmax, axis_b, is_max_b)
+        outline_gizmos[i].matrix_basis = _compose_face_matrix_basis(
+            outline_face_world, mw_rot_scale, cage_rotation, outline_orient, ow, oh
+        )
+
+        if is_front:
+            if not locked:
+                quad_gz.hide = False
+                quad_gz.select_bias = _FACE_QUAD_FRONT_FACING_SELECT_BIAS
+            orient = _AXIS_ORIENT[route]
+            face_world, world_axis = _compute_face_basis(
+                mw,
+                mw_rot,
+                cage_rotation,
+                pivot_local,
+                face_midpoints_local[route],
+                orient,
+            )
+            w, h = _compute_face_quad_scale(bmin, bmax, axis_b, is_max_b)
+            quad_gz.matrix_basis = _compose_face_matrix_basis(face_world, mw_rot_scale, cage_rotation, orient, w, h)
+            quad_gz.axis = world_axis
+            if getattr(quad_gz, "_last_geometry_state", None) != "solid":
+                quad_gz.custom_shape = quad_gz.new_custom_shape("TRIS", _QUAD_TRIS)
+                quad_gz.custom_shape_select = None
+                quad_gz._last_geometry_state = "solid"
+            continue
+
+        # Back-facing: anchor at the back face centre; build halo strips
+        # in the planes of the adjacent FRONT faces, extruded outside
+        # the silhouette toward this face's outward normal.
+        face_world = mw @ (cage_rotation_3x3 @ (face_midpoints_local[route] - pivot_local) + pivot_local)
+        quad_gz.matrix_basis = Matrix.Translation(face_world)
+        quad_gz.axis = (mw_rot @ cage_rotation_3x3 @ Vector(face_outward_axis_local(axis_b, is_max_b))).normalized()
+
+        adjacent_front_routes = [
+            (axis_a, is_max_a)
+            for axis_a in range(3)
+            if axis_a != axis_b
+            for is_max_a in (False, True)
+            if front[route_to_index[(axis_a, is_max_a)]]
+        ]
+        # Per-face world margin: measure the screen-projected length of
+        # ONE world unit along THIS face's outward normal. The world
+        # margin that yields ~N pixels on screen is then ``N / length``.
+        # Foreshortening on oblique faces shortens the projected step,
+        # so the world step must grow to keep the strip the same width
+        # on screen.
+        face_world_margin = 0.0
+        if region is not None:
+            sample_end = box_center_world + quad_gz.axis * 1.0
+            screen_step = _world_segment_to_screen_pixels(region, rv3d, box_center_world, sample_end, min_pixels=0.0)
+            if screen_step > 0.0:
+                face_world_margin = _FACE_QUAD_HALO_TARGET_PIXELS / screen_step
+        if face_world_margin <= 0.0 or not adjacent_front_routes:
+            if not locked:
+                quad_gz.hide = True
+                quad_gz.select_bias = _FACE_QUAD_HALO_FRAME_SELECT_BIAS
+            if getattr(quad_gz, "_last_geometry_state", None) != "empty":
+                quad_gz.custom_shape = quad_gz.new_custom_shape("TRIS", _EMPTY_TRIS)
+                quad_gz.custom_shape_select = None
+                quad_gz._last_geometry_state = "empty"
+            continue
+
+        extrusion_world = quad_gz.axis * face_world_margin
+        extrusion_local = (
+            float(extrusion_world.x),
+            float(extrusion_world.y),
+            float(extrusion_world.z),
+        )
+        all_tris: list[tuple[float, float, float]] = []
+        for axis_a, is_max_a in adjacent_front_routes:
+            edge_keys = _shared_edge_corner_keys(axis_a, is_max_a, axis_b, is_max_b)
+            if edge_keys is None:
+                continue
+            key0, key1 = edge_keys
+            wp0 = corners_world[key0]
+            wp1 = corners_world[key1]
+            local_p0 = (
+                float(wp0.x - face_world.x),
+                float(wp0.y - face_world.y),
+                float(wp0.z - face_world.z),
+            )
+            local_p1 = (
+                float(wp1.x - face_world.x),
+                float(wp1.y - face_world.y),
+                float(wp1.z - face_world.z),
+            )
+            all_tris.extend(_build_strip_tris_relative(local_p0, local_p1, extrusion_local))
+
+        if not locked:
+            quad_gz.hide = False
+            quad_gz.select_bias = _FACE_QUAD_HALO_FRAME_SELECT_BIAS
+
+        corner_keys = _face_corner_keys(axis_b, is_max_b)
+        wc_local = [
+            (
+                float(corners_world[k].x - face_world.x),
+                float(corners_world[k].y - face_world.y),
+                float(corners_world[k].z - face_world.z),
+            )
+            for k in corner_keys
+        ]
+        face_quad_local = [
+            wc_local[0],
+            wc_local[1],
+            wc_local[2],
+            wc_local[0],
+            wc_local[2],
+            wc_local[3],
+        ]
+        if _strips_geometry_changed(quad_gz, tuple(face_quad_local), tuple(all_tris)):
+            quad_gz.custom_shape = quad_gz.new_custom_shape("TRIS", face_quad_local)
+            quad_gz.custom_shape_select = quad_gz.new_custom_shape("TRIS", all_tris)
+        quad_gz._last_geometry_state = "strips"
+
+    # Outline alpha follows ONLY the hovered quad's own state — light
+    # the outline of the face under the cursor, nothing else.
+    if not locked:
+        for outline_gz, quad_gz in zip(outline_gizmos, quad_gizmos, strict=True):
+            lit = bool(getattr(quad_gz, "is_highlight", False))
+            outline_gz.alpha = 1.0 if lit else 0.0
+            outline_gz.alpha_highlight = 1.0 if lit else 0.0
+
+
+__all__ = [
+    "AXIS_COLOR",
+    "FACE_QUAD_ALPHA",
+    "FACE_QUAD_ALPHA_HIGHLIGHT",
+    "FACE_QUAD_SELECT_BIAS",
+    "FACE_ROUTES",
+    "BIM_GT_box_face_outline",
+    "BIM_GT_box_face_quad",
+    "apply_face_quad_layout",
+    "compute_face_resize",
+    "face_outward_axis_local",
+    "front_facing_face_mask",
+    "view_axis_parallel_face_mask",
+]

src/bonsai/bonsai/bim/module/clip_box/gizmos.py

@@ -0,0 +1,312 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Interactive face-quad resize gizmos for the active clip box.
+
+Adapter group that binds the generic :mod:`face_quad` core to a Bonsai
+clip-box Empty: six near-invisible click quads + six edge outlines on
+the cube's faces. Dragging a face does a ONE-SIDED resize — the dragged
+face moves along its outward world normal while the opposite face stays
+put — by writing the empty's ``location`` and ``scale``. Bonsai's
+depsgraph handler then re-arms the clip planes from the new matrix.
+"""
+
+from __future__ import annotations
+
+import contextlib
+from typing import Any
+
+import bpy
+from mathutils import Matrix, Vector
+
+import bonsai.tool as tool
+
+from . import face_quad
+
+# Local-frame bounds of the empty's CUBE display. The display spans
+# ``[-empty_display_size, +empty_display_size]^3``; Bonsai always sets
+# ``empty_display_size = 1.0`` on clip-box hosts, so the local box is
+# the unit cube. The empty's per-axis scale + rotation + translation
+# ride in ``matrix_world``, which the layout helper applies.
+_LOCAL_BMIN = Vector((-1.0, -1.0, -1.0))
+_LOCAL_BMAX = Vector((1.0, 1.0, 1.0))
+
+
+def _world_axis(empty: bpy.types.Object, axis: int, is_max: bool) -> Vector:
+    """Outward world-space unit normal of the ``(axis, is_max)`` face.
+
+    Uses the rotation-only matrix so a negative-scale empty doesn't
+    flip the resulting direction — the visible "+X face" then stays
+    associated with world +X (transformed through rotation).
+    """
+    rot_mat = empty.matrix_world.to_quaternion().to_matrix()
+    n = Vector(rot_mat.col[axis])
+    if n.length <= 0.0:
+        return Vector((0.0, 0.0, 0.0))
+    n.normalize()
+    return n if is_max else -n
+
+
+def _world_half_extent(empty: bpy.types.Object, axis: int) -> float:
+    """The empty's box half-extent along local ``axis`` in WORLD units.
+
+    A CUBE empty's local cube is ``±empty_display_size``; ``matrix_world``
+    stretches it by the column length on ``axis``. So the world
+    half-extent is ``|column[axis]| * empty_display_size``.
+    """
+    col_len = empty.matrix_world.to_3x3().col[axis].length
+    display_size = abs(float(getattr(empty, "empty_display_size", 1.0) or 1.0))
+    return float(col_len) * display_size
+
+
+def _make_face_get_cb(gz: Any, group: Any, axis: int, is_max: bool):
+    """Closure returning the world half-extent at drag start and
+    snapshotting the empty's full transform on the gizmo instance.
+
+    The snapshot lives on the gizmo (not the group) so a PERSISTENT
+    group servicing multiple clip boxes can't bleed one drag's state
+    onto another. Cleared on ``exit`` by the shared face-quad hook.
+    """
+
+    def getter() -> float:
+        empty = group._empty
+        if empty is None:
+            return 0.0
+        existing = getattr(gz, "_drag_snapshot", None)
+        if existing is not None and existing.get("empty_name") == getattr(empty, "name", None):
+            return float(existing["world_half"])
+
+        world_half = _world_half_extent(empty, axis)
+        display_size = abs(float(getattr(empty, "empty_display_size", 1.0) or 1.0))
+        gz._drag_snapshot = {
+            "empty_name": getattr(empty, "name", None),
+            "world_half": world_half,
+            "location": tuple(float(v) for v in empty.location),
+            "scale": tuple(float(v) for v in empty.scale),
+            "display_size": display_size if display_size != 0.0 else 1.0,
+            "world_axis": tuple(_world_axis(empty, axis, is_max)),
+        }
+        return float(world_half)
+
+    return getter
+
+
+def _make_ctrl_click_cb(axis: int, is_max: bool):
+    """Closure that dispatches CTRL+click on a face to the align-view operator.
+
+    Routing through an operator (rather than mutating ``rv3d`` here)
+    keeps the action F3-searchable and undoable.
+    """
+
+    def _callback(_context: Any, _event: Any) -> None:
+        bpy.ops.bim.align_view_to_clip_face("INVOKE_DEFAULT", axis=axis, is_max=is_max)
+
+    return _callback
+
+
+def _make_face_set_cb(gz: Any, group: Any, axis: int, is_max: bool):
+    """Closure that applies a one-sided face resize by writing the
+    empty's ``location`` + ``scale``.
+
+    The modal calls this with ``value = init + delta`` where ``delta``
+    is the cursor's projection onto the face's OUTWARD world normal.
+    Both reads come from ``gz._drag_snapshot`` so every frame is
+    relative to drag start, never compounding.
+    """
+    del is_max  # snapshot's world_axis carries the direction
+
+    def setter(value: float) -> None:
+        empty = group._empty
+        if empty is None:
+            return
+        snap = getattr(gz, "_drag_snapshot", None)
+        if snap is None or snap.get("empty_name") != getattr(empty, "name", None):
+            return
+
+        new_scale_axis, new_location = face_quad.compute_face_resize(
+            value=value,
+            init_world_half=snap["world_half"],
+            init_location=snap["location"],
+            world_axis=snap["world_axis"],
+            display_size=snap["display_size"],
+        )
+        new_scale = list(snap["scale"])
+        # Preserve the sign of the original scale so a user-flipped empty
+        # stays flipped after the resize — compute_face_resize returns a
+        # positive magnitude, the sign is the user's intent to keep.
+        sign = -1.0 if snap["scale"][axis] < 0.0 else 1.0
+        new_scale[axis] = sign * new_scale_axis
+
+        empty.scale = new_scale
+        empty.location = Vector(new_location)
+
+    return setter
+
+
+class OBJECT_GGT_bim_clip_box(bpy.types.GizmoGroup):  # noqa: N801 — Blender bl_idname convention
+    """Face-quad resize handles on the active clip box.
+
+    Renders six near-invisible click-target quads and six colored edge
+    outlines on the active clip-box empty whenever clipping is enabled.
+    Click-and-drag a face to resize one-sided; the opposite face stays
+    put. CTRL+click and plain click fall through to selection.
+    """
+
+    bl_idname = "OBJECT_GGT_bim_clip_box"
+    bl_label = "Bonsai Clip Box Faces"
+    bl_space_type = "VIEW_3D"
+    bl_region_type = "WINDOW"
+    bl_options = {"3D", "PERSISTENT", "SHOW_MODAL_ALL"}
+
+    @classmethod
+    def poll(cls, context: Any) -> bool:
+        scene = getattr(context, "scene", None)
+        if scene is None:
+            return False
+        scene_props = tool.ClipBox.get_scene_props(scene)
+        if not scene_props.enabled or not scene_props.enable_gizmos:
+            return False
+        active_clip_box = tool.ClipBox.get_active_clip_box(scene)
+        if active_clip_box is None:
+            return False
+        # Only render when the user has the active clip box itself
+        # selected — otherwise the face handles would intercept clicks
+        # meant for the geometry behind them.
+        return getattr(context, "active_object", None) is active_clip_box
+
+    @classmethod
+    def setup_keymap(cls, keyconfig):
+        # Bind CLICK_DRAG so plain LEFTMOUSE PRESS passes through to
+        # selection — the user can still click through a near-invisible
+        # face quad to pick a mesh behind it.
+        km = keyconfig.keymaps.new(
+            name=cls.bl_idname,
+            space_type=cls.bl_space_type,
+            region_type=cls.bl_region_type,
+        )
+        km.keymap_items.new("gizmogroup.gizmo_tweak", type="LEFTMOUSE", value="CLICK_DRAG")
+        km.keymap_items.new("gizmogroup.gizmo_tweak", type="LEFTMOUSE", value="PRESS", ctrl=True)
+        return km
+
+    def setup(self, context: Any) -> None:
+        # ``_empty`` is resolved each refresh so the PERSISTENT group
+        # follows whichever clip box is active in the scene PG.
+        self._empty: bpy.types.Object | None = None
+        self._locked = False
+        self._face_routes: list[tuple[int, bool]] = []
+
+        for axis, is_max in face_quad.FACE_ROUTES:
+            gz = self.gizmos.new(face_quad.BIM_GT_box_face_quad.bl_idname)
+            gz._group = self
+            gz._face_axis = axis
+            gz.is_max = is_max
+            gz._drag_snapshot = None
+            gz._last_geometry_state = "solid"
+            gz._strips_cache_key = None
+            gz.color = face_quad.AXIS_COLOR[axis]
+            gz.color_highlight = tuple(min(1.0, c + 0.3) for c in face_quad.AXIS_COLOR[axis])
+            gz.alpha = face_quad.FACE_QUAD_ALPHA
+            gz.alpha_highlight = face_quad.FACE_QUAD_ALPHA_HIGHLIGHT
+            gz.use_draw_modal = True
+            gz.scale_basis = 1.0
+            gz.select_bias = face_quad.FACE_QUAD_SELECT_BIAS
+            gz.move_get_cb = _make_face_get_cb(gz, self, axis, is_max)
+            gz.move_set_cb = _make_face_set_cb(gz, self, axis, is_max)
+            # CTRL+click on a face aligns the viewport to look at it.
+            gz.ctrl_click_cb = _make_ctrl_click_cb(axis, is_max)
+            self._face_routes.append((axis, is_max))
+
+        # Outlines added last so they composite on top of the quad
+        # fills (Blender draws gizmos in creation order).
+        for axis, is_max in face_quad.FACE_ROUTES:
+            ol = self.gizmos.new(face_quad.BIM_GT_box_face_outline.bl_idname)
+            ol._face_axis = axis
+            ol.is_max = is_max
+            ol.color = face_quad.AXIS_COLOR[axis]
+            ol.color_highlight = face_quad.AXIS_COLOR[axis]
+            ol.alpha = 0.0
+            ol.alpha_highlight = 0.0
+            ol.line_width = 2.5
+
+    def _quad_gizmos(self):
+        return self.gizmos[: len(self._face_routes)]
+
+    def _outline_gizmos(self):
+        n = len(self._face_routes)
+        return self.gizmos[n : 2 * n]
+
+    def refresh(self, context: Any) -> None:
+        """State-change path: resolve the active empty, then run the
+        shared face-quad layout so the quads aren't stale for a frame
+        after a selection or active-index change."""
+        empty = tool.ClipBox.get_active_clip_box(context.scene)
+        self._empty = empty
+        if empty is None:
+            for gz in self.gizmos:
+                gz.hide = True
+            return
+        self._layout(context, empty)
+
+    def draw_prepare(self, context: Any) -> None:
+        """Per-redraw — fires on orbit — re-run the layout so the
+        front/back split, halo strips, and outline highlights track
+        the camera and any live G/R/S on the empty."""
+        empty = self._empty
+        if empty is None:
+            return
+        self._layout(context, empty)
+
+    def _layout(self, context: Any, empty: bpy.types.Object) -> None:
+        face_quad.apply_face_quad_layout(
+            quad_gizmos=self._quad_gizmos(),
+            outline_gizmos=self._outline_gizmos(),
+            bmin=_LOCAL_BMIN,
+            bmax=_LOCAL_BMAX,
+            matrix_world=empty.matrix_world,
+            # The empty's rotation rides in matrix_world, so the
+            # box-local OBB rotation is identity.
+            cage_rotation=Matrix.Identity(4),
+            region=getattr(context, "region", None),
+            rv3d=getattr(context, "region_data", None),
+            locked=self._locked,
+        )
+
+    # ---- mutual exclusion (lock siblings during a drag) ------------------
+
+    def _lock_for(self, active_gizmo) -> None:
+        self._locked = True
+        for gz in self.gizmos:
+            if gz is not active_gizmo:
+                with contextlib.suppress(ReferenceError, RuntimeError):
+                    gz.hide = True
+
+    def _unlock_all(self) -> None:
+        self._locked = False
+        for gz in self.gizmos:
+            with contextlib.suppress(ReferenceError, RuntimeError):
+                gz.hide = False
+        # Rebuild caps synchronously so the cross-section overlay
+        # re-forms the instant the user releases the handle, rather
+        # than waiting for the depsgraph's debounced rebuild path.
+        with contextlib.suppress(RuntimeError, ReferenceError):
+            tool.ClipBox.rebuild_caps_now()
+        # Push an undo step so the user can revert a face drag with Ctrl+Z.
+        with contextlib.suppress(RuntimeError):
+            bpy.ops.ed.undo_push(message="Resize Clip Box")

src/bonsai/bonsai/bim/module/clip_box/operator.py

@@ -0,0 +1,294 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+import bpy
+from mathutils import Matrix, Vector
+
+import bonsai.tool as tool
+from bonsai.bim.helper import prop_with_search
+
+from . import data
+
+# NOTE: do NOT add ``from __future__ import annotations`` to this module.
+# PEP 563 stringifies the operator's EnumProperty class annotations, which
+# breaks any introspection that reads ``cls.__annotations__[name].keywords``
+# — including the enum-search helper that draws the search-button icon.
+
+CLIP_BOX_NAME = "ClipBox"
+
+# Display labels for the source-based picker, used for the menu entries and
+# the dialog title. The dict keys are the canonical source-kind identifiers.
+SOURCE_KIND_LABELS: dict[str, str] = {
+    "SPATIAL": "Spatial Element",
+    "CLASS": "Class",
+    "TYPE": "Type",
+    "MATERIAL": "Material",
+    "PROFILE": "Profile",
+    "DRAWING": "Drawing",
+    "STATUS": "Status",
+    "SYSTEM": "System",
+    "GROUP": "Group",
+    "ZONE": "Zone",
+}
+
+
+_SOURCE_ID_DISPATCH = {
+    "SPATIAL": data.spatial_items,
+    "CLASS": data.class_items,
+    "TYPE": data.type_items,
+    "MATERIAL": data.material_items,
+    "PROFILE": data.profile_items,
+    "DRAWING": data.drawing_items,
+    "STATUS": data.status_items,
+    "SYSTEM": data.system_items,
+    "GROUP": data.group_items,
+    "ZONE": data.zone_items,
+}
+
+
+def _source_id_items(self, context):
+    """Dispatch the ``source_id`` enum items based on the picked ``source_kind``."""
+    fn = _SOURCE_ID_DISPATCH.get(self.source_kind)
+    if fn is None:
+        return [(data.NO_OPTIONS_ID, "No options", "")]
+    return fn(self, context)
+
+
+def _source_display_name(kind, source_id):
+    """Human-readable name of the picked source, used in the clip-box name."""
+    if kind == "STATUS":
+        return next((label for value, label in data.STATUS_LABELS if value == source_id), source_id)
+    if kind == "CLASS":
+        # source_id IS the human-readable IFC class name.
+        return source_id
+    ifc = tool.Ifc.get()
+    if ifc is None:
+        return source_id
+    try:
+        entity = ifc.by_id(int(source_id))
+    except (TypeError, ValueError, RuntimeError):
+        return source_id
+    return (getattr(entity, "Name", None) or "Unnamed").strip() or "Unnamed"
+
+
+class BIM_OT_align_view_to_clip_face(bpy.types.Operator):
+    bl_idname = "bim.align_view_to_clip_face"
+    bl_label = "Align View to Clip Box Face"
+    bl_description = "Orient the 3D viewport to look directly at the picked clip-box face"
+    bl_options = {"REGISTER"}
+
+    axis: bpy.props.IntProperty(default=0, options={"SKIP_SAVE"})
+    is_max: bpy.props.BoolProperty(default=True, options={"SKIP_SAVE"})
+
+    def execute(self, context):
+        rv3d = getattr(context, "region_data", None)
+        if rv3d is None:
+            return {"CANCELLED"}
+        clip_box = tool.ClipBox.get_active_clip_box(context.scene)
+        if clip_box is None:
+            return {"CANCELLED"}
+        rot_mat = clip_box.matrix_world.to_quaternion().to_matrix()
+        outward_local = Vector((0.0, 0.0, 0.0))
+        outward_local[self.axis] = 1.0 if self.is_max else -1.0
+        outward = (rot_mat @ outward_local).normalized()
+        if outward.length == 0.0:
+            return {"CANCELLED"}
+        up_world = (rot_mat @ _local_up_for_face(self.axis, self.is_max)).normalized()
+        rv3d.view_rotation = _view_rotation_from_forward_and_up(-outward, up_world)
+        return {"FINISHED"}
+
+
+def _local_up_for_face(axis: int, is_max: bool) -> Vector:
+    """Box-local up direction for a face, following Blender numpad conventions.
+
+    Side faces (local ±X / ±Y normal) → local +Z is up. Top face (local +Z
+    normal) → local +Y is up; bottom face (local -Z normal) → local -Y is
+    up. The caller rotates this through the empty's matrix so the
+    resulting world up axis tracks the box's orientation.
+    """
+    if axis == 2:
+        return Vector((0.0, 1.0, 0.0)) if is_max else Vector((0.0, -1.0, 0.0))
+    return Vector((0.0, 0.0, 1.0))
+
+
+def _view_rotation_from_forward_and_up(forward: Vector, up_hint: Vector) -> "bpy.types.Quaternion":
+    """Build a camera ``view_rotation`` that looks along ``forward`` with
+    ``up_hint`` projected to the camera's local +Y."""
+    back = -forward.normalized()
+    right = up_hint.cross(back)
+    if right.length < 1e-6:
+        right = Vector((1.0, 0.0, 0.0))
+    right.normalize()
+    up = back.cross(right).normalized()
+    return Matrix(
+        (
+            (right.x, up.x, back.x),
+            (right.y, up.y, back.y),
+            (right.z, up.z, back.z),
+        )
+    ).to_quaternion()
+
+
+class BIM_OT_add_clip_box(bpy.types.Operator):
+    bl_idname = "bim.add_clip_box"
+    bl_label = "Add Clip Box"
+    bl_description = (
+        "Create a clip box empty at the 3D cursor. The empty's location, rotation, and scale "
+        "drive the viewport clip planes; resize with S, move with G, rotate with R"
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        # Default to a 20m cube (scale 10 around [-1, +1] local cube) so
+        # the volume covers a typical building storey or two rather than
+        # the meaningless 2m unit cube. The user resizes with S.
+        matrix = Matrix.Translation(context.scene.cursor.location.copy()) @ Matrix.Diagonal((10.0, 10.0, 10.0, 1.0))
+        tool.ClipBox.create_clip_box_empty(context, matrix, name=CLIP_BOX_NAME)
+        return {"FINISHED"}
+
+
+class BIM_OT_add_clip_box_for_source(bpy.types.Operator):
+    bl_idname = "bim.add_clip_box_for_source"
+    bl_label = "Add Clip Box From Source"
+    bl_description = (
+        "Create a clip box sized to a chosen source: a spatial container, IFC type, material, "
+        "profile, drawing camera frustum, element status, system, group, or zone"
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    source_kind: bpy.props.EnumProperty(
+        name="Source Kind",
+        items=[(kind, label, "") for kind, label in SOURCE_KIND_LABELS.items()],
+        default="SPATIAL",
+        options={"SKIP_SAVE"},
+    )
+    source_id: bpy.props.EnumProperty(
+        name="Source",
+        items=_source_id_items,
+        options={"SKIP_SAVE"},
+    )
+
+    def invoke(self, context, event):
+        return context.window_manager.invoke_props_dialog(self)
+
+    def draw(self, context):
+        layout = self.layout
+        label = f"Clip {SOURCE_KIND_LABELS.get(self.source_kind, 'Source')}"
+        # Search button appears once the enum exceeds the helper's threshold,
+        # giving the user a popup picker instead of a plain dropdown.
+        prop_with_search(layout, self, "source_id", text=label)
+
+    def execute(self, context):
+        if not self.source_id or self.source_id == data.NO_OPTIONS_ID:
+            self.report({"ERROR"}, "No source selected.")
+            return {"CANCELLED"}
+        matrix = tool.ClipBox.compute_matrix_for_source(self.source_kind, self.source_id)
+        if matrix is None:
+            kind_label = SOURCE_KIND_LABELS.get(self.source_kind, self.source_kind)
+            self.report(
+                {"ERROR"},
+                f"No elements found for {kind_label} '{_source_display_name(self.source_kind, self.source_id)}'.",
+            )
+            return {"CANCELLED"}
+        name = f"ClipBox.{SOURCE_KIND_LABELS.get(self.source_kind, self.source_kind)}.{_source_display_name(self.source_kind, self.source_id)}"
+        tool.ClipBox.create_clip_box_empty(context, matrix, name=name)
+        return {"FINISHED"}
+
+
+class BIM_OT_remove_clip_box(bpy.types.Operator):
+    bl_idname = "bim.remove_clip_box"
+    bl_label = "Remove Clip Box"
+    bl_description = "Remove this clip box and its host empty"
+    bl_options = {"REGISTER", "UNDO"}
+
+    index: bpy.props.IntProperty(default=-1, options={"SKIP_SAVE"})
+    delete_object: bpy.props.BoolProperty(default=True, name="Delete Host Object")
+
+    def execute(self, context):
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+        index = self.index if self.index >= 0 else scene_props.active_clip_box_index
+        if index < 0 or index >= len(scene_props.clip_boxes):
+            return {"CANCELLED"}
+
+        entry = scene_props.clip_boxes[index]
+        obj = entry.obj
+        scene_props.clip_boxes.remove(index)
+        if scene_props.active_clip_box_index >= len(scene_props.clip_boxes):
+            scene_props.active_clip_box_index = max(0, len(scene_props.clip_boxes) - 1)
+
+        if self.delete_object and obj is not None:
+            bpy.data.objects.remove(obj, do_unlink=True)
+
+        tool.ClipBox.refresh(context.scene)
+        tool.ClipBox.save_to_project_pset(context.scene)
+        return {"FINISHED"}
+
+
+class BIM_OT_set_active_clip_box(bpy.types.Operator):
+    bl_idname = "bim.set_active_clip_box"
+    bl_label = "Set Active Clip Box"
+    bl_description = "Set this clip box as the active one driving the viewport clip"
+    bl_options = {"REGISTER", "UNDO"}
+
+    index: bpy.props.IntProperty(default=-1, options={"SKIP_SAVE"})
+
+    def execute(self, context):
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+        if self.index < 0 or self.index >= len(scene_props.clip_boxes):
+            return {"CANCELLED"}
+        scene_props.active_clip_box_index = self.index
+        return {"FINISHED"}
+
+
+class BIM_OT_toggle_clip_box_enabled(bpy.types.Operator):
+    bl_idname = "bim.toggle_clip_box_enabled"
+    bl_label = "Toggle Clip Box"
+    bl_description = "Toggle whether the active clip box is driving the viewport clip planes"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+        scene_props.enabled = not scene_props.enabled
+        return {"FINISHED"}
+
+
+class BIM_OT_duplicate_clip_box(bpy.types.Operator):
+    bl_idname = "bim.duplicate_clip_box"
+    bl_label = "Duplicate Clip Box"
+    bl_description = "Duplicate this clip box: copy its empty + matrix into a new entry"
+    bl_options = {"REGISTER", "UNDO"}
+
+    index: bpy.props.IntProperty(default=-1, options={"SKIP_SAVE"})
+
+    def execute(self, context):
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+        source_index = self.index if self.index >= 0 else scene_props.active_clip_box_index
+        if source_index < 0 or source_index >= len(scene_props.clip_boxes):
+            return {"CANCELLED"}
+        source = scene_props.clip_boxes[source_index].obj
+        if source is None:
+            return {"CANCELLED"}
+
+        copy = tool.ClipBox.create_clip_box_empty(context, source.matrix_world.copy(), name=source.name)
+        # Preserve the source's display attrs so the duplicate matches.
+        copy.empty_display_type = source.empty_display_type
+        copy.empty_display_size = source.empty_display_size
+        copy.show_in_front = source.show_in_front
+        return {"FINISHED"}

src/bonsai/bonsai/bim/module/clip_box/prop.py

@@ -0,0 +1,165 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import bpy
+from bpy.types import PropertyGroup
+
+import bonsai.tool as tool
+from bonsai.bim.prop import ObjProperty
+
+
+class BIMClipBoxProperties(PropertyGroup):
+    """Per-object marker for a clip-box host empty.
+
+    The host empty's ``matrix_world`` is the single source of truth for
+    the clip box's pose and dimensions: translation = box centre,
+    rotation = box orientation, per-axis scale = world half-extents. The
+    visible cube comes from the empty's CUBE display.
+
+    Only ``is_clip_box`` lives here; visibility (``enabled``) and overlay
+    (``show_caps``) are global per-file and live on the Scene PG.
+    """
+
+    is_clip_box: bpy.props.BoolProperty(
+        default=False,
+        description="True when this empty was created as a clip-box host. Internal flag; not user-edited.",
+    )
+
+    if TYPE_CHECKING:
+        is_clip_box: bool
+
+
+def update_active_clip_box_index(self, context):
+    tool.ClipBox.schedule_refresh()
+    tool.ClipBox.select_active_clip_box(context)
+    # Rebuild caps for the new active box's clip volume.
+    tool.ClipBox.invalidate_cap_cache(immediate=True)
+
+
+def update_show_caps(self, context):
+    tool.ClipBox.schedule_refresh()
+    # Off → on must trigger a rebuild so caps reappear immediately rather
+    # than wait for the next depsgraph tick. The rebuild is a no-op when
+    # show_caps is now False (it clears and returns), so this is safe in
+    # both directions.
+    tool.ClipBox.invalidate_cap_cache()
+
+
+def update_enabled(self, context):
+    tool.ClipBox.schedule_refresh()
+
+
+def update_clip_only_ifc_products(self, context):
+    # The eligibility set for capping changed — drop the cache and let the
+    # debounced rebuild pick up the new objects on the next idle tick.
+    tool.ClipBox.invalidate_cap_cache()
+
+
+def update_include_linked_ifc(self, context):
+    tool.ClipBox.invalidate_cap_cache()
+
+
+class BIMSceneClipBoxProperties(PropertyGroup):
+    """Scene-level registry of clip boxes in this file.
+
+    Multiple boxes may exist; ``active_clip_box_index`` selects which one
+    drives the viewport clip at any time. ``enabled`` and ``show_caps``
+    are global because the user's intent ("hide everything outside the
+    box", "draw cap overlays") applies file-wide, not per box.
+
+    ``enabled`` is intentionally not persisted to the project pset:
+    opening a fresh IFC should never silently hide geometry behind a
+    remembered toggle. Selecting any clip-box empty in the viewport
+    re-arms it (see :meth:`tool.ClipBox._sync_active_to_selection`).
+    """
+
+    clip_boxes: bpy.props.CollectionProperty(type=ObjProperty)
+    active_clip_box_index: bpy.props.IntProperty(
+        default=0,
+        min=0,
+        update=update_active_clip_box_index,
+        description="Index of the clip box currently driving the viewport clip planes",
+    )
+    enabled: bpy.props.BoolProperty(
+        name="Enabled",
+        default=False,
+        update=update_enabled,
+        description="When enabled, the active clip box hides all viewport geometry outside its 6 faces",
+    )
+    show_caps: bpy.props.BoolProperty(
+        name="Show Caps",
+        default=True,
+        update=update_show_caps,
+        description=(
+            "Draw filled cross-section caps where IFC product geometry "
+            "crosses the active clip planes. Disable for performance on "
+            "very heavy scenes"
+        ),
+    )
+    # Stored on the Scene PG so Blender persists it in the .blend; deliberately
+    # NOT written to the project pset so the IFC stays portable across users
+    # who may have different Blender-side reference geometry to clip.
+    clip_only_ifc_products: bpy.props.BoolProperty(
+        name="Only IFC Products",
+        default=True,
+        update=update_clip_only_ifc_products,
+        description=(
+            "When enabled, only IFC element geometry gets cross-section caps. "
+            "Disable to also cap Blender-side reference meshes (sketches, "
+            "imported obj, primitive cubes, …)"
+        ),
+    )
+    # Opt-in inclusion of geometry sitting inside loaded Project › Links
+    # collection-instance empties. Off by default — linked IFCs commonly
+    # carry the entire site / structural / MEP context, and bisecting
+    # them on every clip-box edit can be expensive.
+    include_linked_ifc: bpy.props.BoolProperty(
+        name="Include Linked IFC",
+        default=False,
+        update=update_include_linked_ifc,
+        description=(
+            "Also generate cross-section caps for geometry inside linked "
+            "IFC files (Project ▸ Links). Off by default — linked IFCs may "
+            "carry the entire site / structural backbone, and capping them "
+            "adds per-mesh bisect cost on every clip-box edit"
+        ),
+    )
+    # Also Scene-only — gizmo visibility is a per-user editing preference,
+    # not a portable IFC property.
+    enable_gizmos: bpy.props.BoolProperty(
+        name="Show Face Handles",
+        default=True,
+        description=(
+            "Show interactive face-resize handles on the active clip box. "
+            "Disable to fall back to plain G/R/S transforms on the empty"
+        ),
+    )
+
+    if TYPE_CHECKING:
+        active_clip_box_index: int
+        enabled: bool
+        show_caps: bool
+        clip_only_ifc_products: bool
+        include_linked_ifc: bool
+        enable_gizmos: bool

src/bonsai/bonsai/bim/module/clip_box/ui.py

@@ -0,0 +1,145 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+from __future__ import annotations
+
+from bpy.types import Menu, Panel, UIList
+
+import bonsai.tool as tool
+
+# Per-kind icon for the source-picker menu. Picked from Blender's built-in
+# icon set; semantically close to the kind so users can scan the menu visually.
+_SOURCE_MENU_ENTRIES: tuple[tuple[str, str, str], ...] = (
+    ("SPATIAL", "Clip Spatial Element", "OUTLINER_COLLECTION"),
+    ("CLASS", "Clip by Class", "BLANK1"),
+    ("TYPE", "Clip Type", "FILE_3D"),
+    ("MATERIAL", "Clip Material", "MATERIAL"),
+    ("PROFILE", "Clip Profile", "MESH_CIRCLE"),
+    ("DRAWING", "Clip Drawing Extents", "CAMERA_DATA"),
+    ("STATUS", "Clip by Status", "INFO"),
+    ("SYSTEM", "Clip by System", "MOD_FLUID"),
+    ("GROUP", "Clip by Group", "OUTLINER_OB_GROUP_INSTANCE"),
+    ("ZONE", "Clip by Zone", "MOD_LATTICE"),
+)
+
+
+class BIM_MT_clip_box_add_for_source(Menu):
+    bl_idname = "BIM_MT_clip_box_add_for_source"
+    bl_label = "Add Clip Box From Source"
+
+    def draw(self, context):
+        layout = self.layout
+        for kind, label, icon in _SOURCE_MENU_ENTRIES:
+            op = layout.operator("bim.add_clip_box_for_source", text=label, icon=icon)
+            op.source_kind = kind
+
+
+class BIM_MT_clip_box_settings(Menu):
+    bl_idname = "BIM_MT_clip_box_settings"
+    bl_label = "Clip Box Settings"
+
+    def draw(self, context):
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+        self.layout.prop(scene_props, "clip_only_ifc_products")
+        self.layout.prop(scene_props, "include_linked_ifc")
+        self.layout.prop(scene_props, "enable_gizmos")
+
+
+class BIM_MT_clip_box_info(Menu):
+    bl_idname = "BIM_MT_clip_box_info"
+    bl_label = "Clip Box Face Handles"
+
+    def draw(self, context):
+        layout = self.layout
+        layout.label(text="Face Handles", icon="INFO")
+        layout.separator()
+        layout.label(text="Drag a face to resize the clip box on that axis.")
+        layout.label(text="The opposite face stays fixed (one-sided resize).")
+        layout.label(text="Ctrl+Click a face to align the viewport to it.")
+        layout.separator()
+        layout.label(text="Toggle handles from the Settings (gear) menu.")
+
+
+class BIM_UL_clip_box(UIList):
+    def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index, flt_flag):
+        obj = item.obj
+        row = layout.row(align=True)
+        if obj is None:
+            # Host empty was deleted from outliner; still expose the
+            # remove button so the orphan entry isn't permanent.
+            row.label(text="(missing)", icon="ERROR")
+            row.operator("bim.remove_clip_box", text="", icon="X", emboss=False).index = index
+            return
+        row.prop(obj, "name", text="", emboss=False, icon="MESH_CUBE")
+        row.operator("bim.duplicate_clip_box", text="", icon="DUPLICATE", emboss=False).index = index
+        row.operator("bim.remove_clip_box", text="", icon="X", emboss=False).index = index
+
+
+class BIM_PT_clip_box(Panel):
+    bl_idname = "BIM_PT_clip_box"
+    bl_label = "Clip Box"
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+    bl_options = {"DEFAULT_CLOSED"}
+    bl_parent_id = "BIM_PT_tab_sandbox"
+
+    def draw(self, context):
+        layout = self.layout
+        scene_props = tool.ClipBox.get_scene_props(context.scene)
+
+        toggles = layout.row(align=True)
+        toggles.scale_y = 2.0
+        toggles.prop(
+            scene_props,
+            "enabled",
+            text="Enable Clipping",
+            icon="HIDE_OFF" if scene_props.enabled else "HIDE_ON",
+            toggle=True,
+        )
+        toggles.prop(scene_props, "show_caps", text="Show Caps", icon="MOD_SOLIDIFY", toggle=True)
+        toggles.menu("BIM_MT_clip_box_settings", icon="PREFERENCES", text="")
+        toggles.menu("BIM_MT_clip_box_info", icon="INFO", text="")
+
+        layout.separator()
+        row = layout.row(align=True)
+        row.operator("bim.add_clip_box", icon="ADD", text="Add Clip Box")
+        row.menu("BIM_MT_clip_box_add_for_source", icon="DOWNARROW_HLT", text="")
+
+        layout.template_list(
+            "BIM_UL_clip_box",
+            "",
+            scene_props,
+            "clip_boxes",
+            scene_props,
+            "active_clip_box_index",
+            rows=3,
+        )
+
+        obj = tool.ClipBox.get_active_clip_box(context.scene)
+        if obj is None:
+            layout.label(text="No active clip box", icon="INFO")
+            return
+
+        col = layout.column(align=True)
+        col.label(text="Edit the empty with G / R / S to move / rotate / resize")
+        col.prop(obj, "location")
+        col.prop(obj, "rotation_euler")
+        col.prop(obj, "scale")

src/bonsai/bonsai/bim/module/document/data.py

@@ -127,36 +127,25 @@ class ObjectDocumentData:
                 identification = None
 
                 if is_information:
-                    if tool.Ifc.get_schema() == "IFC2X3":
-                        identification = relating_document.DocumentId
-                    else:
-                        identification = relating_document.Identification
+                    identification = tool.Document.get_document_information_id(relating_document)
 
                     location = getattr(relating_document, "Location", None)
                     description = getattr(relating_document, "Description", "No description")
                 else:
                     description = relating_document.Description
-                    if tool.Ifc.get_schema() == "IFC2X3":
-                        reference_to_document = relating_document.ReferenceToDocument
-                        if not name and reference_to_document:
-                            name = reference_to_document[0].Name
+                    referenced_document = tool.Document.get_reference_document(relating_document)
 
-                        identification = relating_document.ItemReference
-                        if not identification and reference_to_document:
-                            identification = reference_to_document[0].DocumentId
-                        location = relating_document.Location
-                    else:
-                        referenced_document = relating_document.ReferencedDocument
-                        if not name and referenced_document:
-                            name = referenced_document.Name
+                    if not name and referenced_document:
+                        name = referenced_document.Name
 
-                        identification = relating_document.Identification
-                        if not identification and referenced_document:
-                            identification = referenced_document.Identification
+                    identification = tool.Document.get_external_reference_id(relating_document)
+                    if not identification and referenced_document:
+                        identification = tool.Document.get_document_information_id(referenced_document)
 
-                        location = relating_document.Location
-                        if location is None and referenced_document:
-                            location = referenced_document.Location
+                    location = relating_document.Location
+                    # IFC2X3 IfcDocumentInformation has no Location to fall back to.
+                    if location is None and referenced_document and tool.Ifc.get_schema() != "IFC2X3":
+                        location = referenced_document.Location
 
                 location = cls.convert_to_file_uri(location) if location else None
 

src/bonsai/bonsai/bim/module/drawing/gizmos.py

@@ -82,7 +82,15 @@ import math
 from collections.abc import Callable, Iterator
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any, ClassVar, Literal, Optional, Protocol, runtime_checkable
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    ClassVar,
+    Literal,
+    Optional,
+    Protocol,
+    runtime_checkable,
+)
 
 import blf
 import bpy
@@ -105,6 +113,9 @@ from mathutils.kdtree import KDTree
 import bonsai.tool as tool
 from bonsai.bim.module.drawing.shaders import ExtrusionGuidesShader
 
+if TYPE_CHECKING:
+    import bmesh
+
 SNAP_POINT_SIZE = 10.0
 SNAP_POINT_COLOR = (1.0, 0.5, 0.0, 1.0)
 SNAP_MAX_RADIUS = 50.0
@@ -159,6 +170,38 @@ _SPECIAL = {"=", " "}  # Formula prefix, spaces
 NUMERIC_INPUT_CHARS = _DIGITS | _OPERATORS | _METRIC_UNITS | _IMPERIAL_UNITS | _SPECIAL
 
 
+def _is_transform_modal_active(context) -> bool:
+    """Module-local alias for ``tool.Blender.is_transform_modal_active``.
+
+    Preserved as a name so AST scans and call sites in this file stay
+    decoupled from the helper's home module.
+    """
+    return tool.Blender.is_transform_modal_active(context)
+
+
+def _hide_all_non_modal_gizmos(group) -> None:
+    """Set ``hide = True`` on every gizmo in ``group`` whose own ``is_modal``
+    is False. Used by parametric ``draw_prepare`` to suppress visible
+    re-positioning while a transform modal is dragging ``matrix_world``."""
+    for gz in group.gizmos:
+        if not getattr(gz, "is_modal", False):
+            gz.hide = True
+
+
+def apply_transform_modal_draw_gate(group, context) -> bool:
+    """Combined gate for ``draw_prepare`` overrides: hide non-modal gizmos and
+    return ``True`` when a Blender transform modal is dragging matrix_world.
+
+    Returns ``False`` when no transform modal is active so callers can fall
+    through to their normal positioning logic. ``True`` means the caller must
+    early-return without touching matrix_basis — the hidden gizmos will be
+    re-shown on the next idle frame once the modal exits."""
+    if not _is_transform_modal_active(context):
+        return False
+    _hide_all_non_modal_gizmos(group)
+    return True
+
+
 class GizmoColor(Enum):
     """Color identifiers for dimension gizmos.
 
@@ -1694,6 +1737,33 @@ def billboarded_at(world_pos: Vector, billboard_rot: Matrix, scale: float = DEFA
     return Matrix.Translation(world_pos) @ billboard_rot @ Matrix.Scale(scale, 4)
 
 
+def billboarded_along_axis(
+    world_pos: Vector,
+    billboard_rot: Matrix,
+    axis_world: Vector,
+    scale: float = DEFAULT_BILLBOARD_SCALE,
+) -> Matrix:
+    """Composed matrix_basis like ``billboarded_at`` but with local +X
+    rotated about the camera-forward axis to align with ``axis_world``
+    projected onto the screen plane.
+
+    The gizmo still faces the camera (local +Z stays along camera-forward),
+    only its in-plane orientation changes. Falls back to plain
+    ``billboarded_at`` when the axis is near-parallel to the view direction
+    (no usable screen projection)."""
+    camera_forward = billboard_rot @ Vector((0.0, 0.0, 1.0))
+    projected = axis_world - camera_forward * axis_world.dot(camera_forward)
+    if projected.length < 1e-4:
+        return billboarded_at(world_pos, billboard_rot, scale)
+    projected.normalize()
+    y_axis = camera_forward.cross(projected).normalized()
+    rot = Matrix.Identity(4)
+    rot[0][:3] = (projected.x, y_axis.x, camera_forward.x)
+    rot[1][:3] = (projected.y, y_axis.y, camera_forward.y)
+    rot[2][:3] = (projected.z, y_axis.z, camera_forward.z)
+    return Matrix.Translation(world_pos) @ rot @ Matrix.Scale(scale, 4)
+
+
 def get_screen_up(billboard_rot: Matrix) -> Vector:
     """Camera's screen-up direction in world space — local +Y of the billboard
     rotation. Use to lift a gizmo above an anchor in a way that stays
@@ -1976,7 +2046,9 @@ class TexturedQuadGizmoMixin(StaticTrisGizmoMixin):
 
     def setup(self) -> None:
         super().setup()
-        from bonsai.bim.module.drawing import gizmo_textures
+        from bonsai.bim.module.drawing import (
+            gizmo_textures,  # ty: ignore[unresolved-import]
+        )
 
         self._quad_batch = batch_for_shader(
             gizmo_textures.get_shader(),
@@ -1985,7 +2057,9 @@ class TexturedQuadGizmoMixin(StaticTrisGizmoMixin):
         )
 
     def draw(self, context: bpy.types.Context) -> None:
-        from bonsai.bim.module.drawing import gizmo_textures
+        from bonsai.bim.module.drawing import (
+            gizmo_textures,  # ty: ignore[unresolved-import]
+        )
 
         texture = gizmo_textures.get_icon_texture(self.icon_name)
         if texture is None:
@@ -3255,11 +3329,16 @@ class GizmoArc(StaticTrisGizmoMixin, bpy.types.Gizmo):
     """Static quarter-arc glyph for swing visualisation.
 
     Consumers needing the mirrored (RIGHT) visual apply a flip-X matrix to
-    ``matrix_basis``."""
+    ``matrix_basis``. ``outline_alpha = 0.0`` suppresses the inherited 8-pass
+    dark halo: an open curve has no enclosed silhouette for the dilation to
+    ring, so the offset passes read as ghost arcs rather than a uniform
+    outline. The arc's own cross-section thickness keeps it legible without
+    the halo."""
 
     bl_idname = "VIEW3D_GT_arc"
     __slots__ = ("custom_shape",)
     tris = ARC_TRIS_DEFAULT
+    outline_alpha = 0.0
 
 
 def _link_toggle_icon_tris(broken: bool) -> tuple[tuple[float, float, float], ...]:
@@ -4786,7 +4865,14 @@ class GizmoDimension(GizmoMovable):
 
         self.init_value = click_distance
 
-        if self.initial_snap_state and self.active_obj:
+        # Schematic gizmos opt out of dimension snap. Force the header
+        # indicator to ``off`` for the drag's duration so the user sees the
+        # state matches behaviour; ``exit`` restores ``initial_snap_state``.
+        # Skipping the snap cache here also avoids the per-drag mesh probe.
+        snap_supported = getattr(self.gizmo_group, "snap_enabled_on_dimensions", True)
+        if not snap_supported:
+            context.scene.tool_settings.use_snap = False
+        elif self.initial_snap_state and self.active_obj:
             build_snap_cache(context, self.active_obj)
             self._snap_cache_built = True
 
@@ -4828,11 +4914,18 @@ class GizmoDimension(GizmoMovable):
         if not region or not rv3d:
             return {"RUNNING_MODAL"}
 
-        tool_settings.use_snap = not self.initial_snap_state if event.ctrl else self.initial_snap_state
+        # Group-level opt-out: schematic gizmos float in viewport space, so
+        # global-snap-to-scene-vertices would produce spurious value jumps.
+        # The fallback (``True``) covers any gizmo whose group is not a
+        # ``BaseParametricGizmoGroup``.
+        snap_supported = getattr(self.gizmo_group, "snap_enabled_on_dimensions", True)
 
-        if tool_settings.use_snap and not self._snap_cache_built and self.active_obj:
-            build_snap_cache(context, self.active_obj)
-            self._snap_cache_built = True
+        if snap_supported:
+            tool_settings.use_snap = not self.initial_snap_state if event.ctrl else self.initial_snap_state
+
+            if tool_settings.use_snap and not self._snap_cache_built and self.active_obj:
+                build_snap_cache(context, self.active_obj)
+                self._snap_cache_built = True
 
         current_coord = (event.mouse_region_x, event.mouse_region_y)
 
@@ -4856,7 +4949,7 @@ class GizmoDimension(GizmoMovable):
 
         delta = (current_3d - self.start_location).dot(axis_direction)
 
-        if tool_settings.use_snap and self.active_obj:
+        if snap_supported and tool_settings.use_snap and self.active_obj:
             # Snap the dimension tip (not mouse position) to target
             # Calculate where the dimension tip would be with current delta
             # The tip is at: gizmo_origin + axis * (init_value + delta)
@@ -4998,6 +5091,8 @@ class BillboardingGizmoGroupMixin:
         self.position_gizmos(context)
 
     def draw_prepare(self, context: bpy.types.Context) -> None:
+        if apply_transform_modal_draw_gate(self, context):
+            return
         self.position_gizmos(context)
 
     def setup_icon_gizmo(
@@ -5227,6 +5322,13 @@ class BaseParametricGizmoGroup:
     # Pre-computed flip matrix for negative value handling (180° rotation around Z)
     FLIP_MATRIX = Matrix.Rotation(math.pi, 4, "Z")
 
+    # Default: dimension drags respect Blender's global snap (Ctrl-toggleable
+    # during drag). Subclasses whose dimensions float in viewport space rather
+    # than aligning to real-world geometry should override to ``False`` —
+    # snapping to scene vertices in that case produces spurious value jumps
+    # as the mouse crosses unrelated meshes.
+    snap_enabled_on_dimensions: bool = True
+
     # === Icon Gizmo Layout (meters) ===
     # Icons are positioned in a horizontal row above the element:
     #   [Validate] [Cancel] [Cycle]
@@ -5652,6 +5754,8 @@ class BaseParametricGizmoGroup:
 
         if preview_base.any_preview_active(context):
             return False
+        if _is_transform_modal_active(context):
+            return False
         if cls.gizmo_pref_name:
             prefs = tool.Blender.get_addon_preferences()
             if not getattr(prefs.gizmos, cls.gizmo_pref_name, True):
@@ -6416,6 +6520,8 @@ class BaseParametricGizmoGroup:
         """
         if not self.is_setup_complete():
             return
+        if apply_transform_modal_draw_gate(self, context):
+            return
         obj = context.active_object
         if not obj:
             return
@@ -6483,6 +6589,11 @@ class BaseSchematicGizmoGroup(BaseParametricGizmoGroup):
     # list and become no-ops. The schematic equivalents below take their place.
     dimension_gizmo_props: list[DimensionGizmoConfig] = []
 
+    # Schematic dimensions float in billboarded viewport space, not aligned to
+    # real-world geometry. Snapping the dragged tip to scene vertices would
+    # produce nonsensical value jumps as the mouse crosses unrelated meshes.
+    snap_enabled_on_dimensions: bool = False
+
     # Declarative dimension configuration consumed by ``setup_schematic_dimensions``
     # and ``update_schematic_dimensions``. Each config produces one
     # ``BIM_GT_gizmo_dimension`` instance positioned at a schematic-local
@@ -6622,6 +6733,8 @@ class BaseSchematicGizmoGroup(BaseParametricGizmoGroup):
     def draw_prepare(self, context: bpy.types.Context) -> None:
         if not self.is_setup_complete():
             return
+        if apply_transform_modal_draw_gate(self, context):
+            return
         obj = context.active_object
         if not obj:
             return
@@ -7028,6 +7141,8 @@ class BaseIconActionGroup(BillboardingGizmoGroupMixin):
             return False
         if not tool.Blender.are_viewport_gizmos_enabled():
             return False
+        if _is_transform_modal_active(context):
+            return False
         return cls.is_eligible_object(obj)
 
     def setup(self, context: bpy.types.Context) -> None:

src/bonsai/bonsai/bim/module/drawing/handler.py

@@ -50,6 +50,9 @@ def set_active_camera_resolution(scene: bpy.types.Scene) -> None:
     if camera.type != props.camera_type:
         camera.type = props.camera_type
 
+    if props.update_props and (drawing := tool.Ifc.get_entity(camera_obj)):
+        tool.Drawing.sync_perspective_camera_shifts(drawing, camera)
+
     ortho_scale, aspect_ratio = props.get_scale_and_aspect_ratio()
     scene_render = scene.render
     if (camera.ortho_scale != ortho_scale) or not tool.Cad.is_x(

src/bonsai/bonsai/bim/module/drawing/helper.py

@@ -189,14 +189,20 @@ def format_distance(
             if hasattr(length_unit, "Prefix") and length_unit.Prefix:
                 unit_length = length_unit.Prefix + length_unit.Name
             unit_length_mapping = {
+                "MILE": "MILES",
                 "FOOT": "FEET",
                 "INCH": "INCHES",
+                "KILOMETRE": "KILOMETERS",
                 "METRE": "METERS",
                 "DECIMETRE": "DECIMETERS",
                 "CENTIMETRE": "CENTIMETERS",
                 "MILLIMETRE": "MILLIMETERS",
+                "MICROMETRE": "MICROMETERS",
             }
-            unit_length = unit_length_mapping[unit_length]
+            # Fall through for units without a dedicated formatter (e.g.
+            # HECTOMETRE) so they use the adaptive branch instead of a
+            # KeyError (#8255).
+            unit_length = unit_length_mapping.get(unit_length, unit_length)
         # For now we only format area in IFC Units
         if area_unit := ifcopenshell.util.unit.get_project_unit(tool.Ifc.get(), "AREAUNIT"):
             area_unit_symbol = " " + ifcopenshell.util.unit.get_unit_symbol(area_unit)

src/bonsai/bonsai/bim/module/drawing/operator.py

@@ -57,7 +57,7 @@ import shapely
 from bpy_extras.image_utils import load_image
 from bpy_extras.io_utils import ImportHelper
 from lxml import etree
-from mathutils import Color, Vector
+from mathutils import Color, Matrix, Vector
 
 import bonsai.bim.export_ifc
 import bonsai.bim.handler
@@ -602,6 +602,7 @@ class CreateDrawing(bpy.types.Operator):
         context_type: Literal["body", "annotation"],
         drawing_elements: set[ifcopenshell.entity_instance],
         target_view: str,
+        link_matrix: Optional[Matrix] = None,
     ) -> None:
         drawing_elements = drawing_elements.copy()
         contexts_: list[list[int]] = getattr(contexts, context_type)
@@ -613,9 +614,19 @@ class CreateDrawing(bpy.types.Operator):
                 geom_settings.set("dimensionality", ifcopenshell.ifcopenshell_wrapper.CURVES_SURFACES_AND_SOLIDS)
                 geom_settings.set("iterator-output", ifcopenshell.ifcopenshell_wrapper.NATIVE)
 
-                if ifc.by_id(context[0]).ContextType == "Plan" and "PLAN_VIEW" in target_view:
+                is_plan = ifc.by_id(context[0]).ContextType == "Plan" and "PLAN_VIEW" in target_view
+                z_offset = (0.002 if target_view == "PLAN_VIEW" else -0.002) if is_plan else 0.0
+
+                if link_matrix is not None:
+                    unit_scale = ifcopenshell.util.unit.calculate_unit_scale(ifc)
+                    t = link_matrix.to_translation()
+                    offset = (t.x / unit_scale, t.y / unit_scale, t.z / unit_scale + z_offset)
+                    geom_settings.set("model-offset", offset)
+                    q = link_matrix.to_quaternion()
+                    geom_settings.set("model-rotation", (q.x, q.y, q.z, q.w))
+                elif z_offset:
                     # A 2mm Z offset to combat Z-fighting in plan or RCPs
-                    geom_settings.set("model-offset", (0.0, 0.0, 0.002 if target_view == "PLAN_VIEW" else -0.002))
+                    geom_settings.set("model-offset", (0.0, 0.0, z_offset))
 
                 geom_settings.set("context-ids", context)
                 it = ifcopenshell.geom.iterator(
@@ -923,11 +934,16 @@ class CreateDrawing(bpy.types.Operator):
 
         bim_props = tool.Blender.get_bim_props()
         prefs = tool.Blender.get_addon_preferences()
-        files = {bim_props.ifc_file: tool.Ifc.get()}
+        # Map ifc_path → (ifc_file, link_matrix); main file has no link_matrix (None)
+        files: dict[str, tuple[ifcopenshell.file, Optional[Matrix]]] = {bim_props.ifc_file: (tool.Ifc.get(), None)}
 
         props = tool.Project.get_project_props()
         for link in props.get_loaded_links_for_drawings():
-            files[link.filepath] = self.get_linked_file(link)
+            try:
+                link_matrix = tool.Project.calculate_link_matrix(link)
+            except Exception:
+                link_matrix = None
+            files[link.filepath] = (self.get_linked_file(link), link_matrix)
 
         target_view = ifcopenshell.util.element.get_psets(self.camera_element)["EPset_Drawing"]["TargetView"]
         self.setup_serialiser(target_view)
@@ -935,7 +951,13 @@ class CreateDrawing(bpy.types.Operator):
         tree = ifcopenshell.geom.tree()
         tree.enable_face_styles(True)
 
-        for ifc_path, ifc in files.items():
+        # Accumulated across every file in the loop below (main model plus any
+        # linked models) so the SHAPELY fill pass after the loop covers all of
+        # them, not just whichever file happened to be processed last.
+        raycast_objs = set()
+        elements_with_faces = set()
+
+        for ifc_path, (ifc, link_matrix) in files.items():
             # Don't use draw.main() just whilst we're prototyping and experimenting
             # TODO: hash paths are never used
             ifc_hash = hashlib.md5(ifc_path.encode("utf-8")).hexdigest()
@@ -944,13 +966,24 @@ class CreateDrawing(bpy.types.Operator):
             self.serialiser.setFile(ifc)
             drawing_elements = tool.Drawing.get_drawing_elements(self.camera_element, ifc_file=ifc)
 
+            if self.cprops.fill_mode == "SHAPELY":
+                for element in drawing_elements.copy():
+                    if element.is_a("IfcAnnotation"):
+                        continue
+                    obj = tool.Ifc.get_object(element)
+                    if obj and obj.type == "MESH" and len(obj.data.polygons):
+                        elements_with_faces.add(element.GlobalId)
+                        raycast_objs.add(obj)
+
             # Get all representation contexts to see what we're dealing with.
             # Drawings only draw bodies and annotations (and facetation, due to a Revit bug).
             # A drawing prioritises a target view context first, followed by a model view context as a fallback.
             # Specifically for PLAN_VIEW and REFLECTED_PLAN_VIEW, any Plan context is also prioritised.
             contexts = self.get_linework_contexts(ifc, target_view)
-            self.serialize_contexts_elements(ifc, tree, contexts, "body", drawing_elements, target_view)
-            self.serialize_contexts_elements(ifc, tree, contexts, "annotation", drawing_elements, target_view)
+            self.serialize_contexts_elements(ifc, tree, contexts, "body", drawing_elements, target_view, link_matrix)
+            self.serialize_contexts_elements(
+                ifc, tree, contexts, "annotation", drawing_elements, target_view, link_matrix
+            )
 
             if tool.Ifc.get() == ifc and self.camera_element not in drawing_elements:
                 with profile("Camera element"):
@@ -1017,16 +1050,6 @@ class CreateDrawing(bpy.types.Operator):
             # shapely variant
             group = root.find("{http://www.w3.org/2000/svg}g")
 
-            raycast_objs = set()
-            elements_with_faces = set()
-            for element in drawing_elements.copy():
-                if element.is_a("IfcAnnotation"):
-                    continue
-                obj = tool.Ifc.get_object(element)
-                if obj and obj.type == "MESH" and len(obj.data.polygons):
-                    elements_with_faces.add(element.GlobalId)
-                    raycast_objs.add(obj)
-
             projections = root.xpath(
                 ".//svg:g[contains(@class, 'projection')]", namespaces={"svg": "http://www.w3.org/2000/svg"}
             )
@@ -1683,6 +1706,12 @@ class CreateDrawing(bpy.types.Operator):
             key=lambda a: (
                 tool.Drawing.get_annotation_z_index(a),
                 1 if ifcopenshell.util.element.get_predefined_type(a) == "TEXT" else 0,
+                # Deterministic tiebreaker so equal-priority annotations keep a
+                # stable order across sessions. Without it the order comes from
+                # the set union above, which depends on entity hashes (and thus
+                # the file pointer), shuffling annotations between Blender
+                # restarts. See #6608.
+                a.id(),
             ),
         )
 
@@ -2319,7 +2348,10 @@ class ActivateDrawingBase(tool.Ifc.Operator):
     bl_description = (
         "Activates the selected drawing view.\n\n"
         + "ALT+CLICK to keep the viewport position.\n\n"
-        + "SHIFT+CLICK to load a quick preview of the drawing view"
+        + "SHIFT+CLICK to load a quick preview of the drawing view.\n\n"
+        + "SHIFT+CTRL+CLICK to load the annotations of all selected drawings without switching views, "
+        + "then select their cameras (the first selected drawing's camera becomes active).\n\n"
+        + "SHIFT+CTRL+ALT+CLICK to do the same but also select the annotations, not just the cameras"
     )
 
     drawing: bpy.props.IntProperty()
@@ -2335,13 +2367,32 @@ class ActivateDrawingBase(tool.Ifc.Operator):
         default=False,
         options={"SKIP_SAVE"},
     )
+    load_selected_annotations: bpy.props.BoolProperty(
+        name="Load Selected Annotations",
+        description="Load the annotations of all selected drawings without switching the active view.",
+        default=False,
+        options={"SKIP_SAVE"},
+    )
+    include_annotations_in_selection: bpy.props.BoolProperty(
+        name="Include Annotations In Selection",
+        description="Also select the loaded annotation objects, not just the drawing cameras.",
+        default=False,
+        options={"SKIP_SAVE"},
+    )
 
     if TYPE_CHECKING:
         drawing: int
         should_view_from_camera: bool
         use_quick_preview: bool
+        load_selected_annotations: bool
+        include_annotations_in_selection: bool
 
     def invoke(self, context, event) -> set["rna_enums.OperatorReturnItems"]:
+        if event.type == "LEFTMOUSE" and event.shift and event.ctrl:
+            self.load_selected_annotations = True
+            if event.alt:
+                self.include_annotations_in_selection = True
+            return self.execute(context)
         if event.type == "LEFTMOUSE" and event.alt:
             self.should_view_from_camera = False
         if event.type == "LEFTMOUSE" and event.shift:
@@ -2354,6 +2405,37 @@ class ActivateDrawingBase(tool.Ifc.Operator):
         if props.is_editing_drawings == False:
             bpy.ops.bim.load_drawings()
 
+        if self.load_selected_annotations:
+            objs_to_select = []
+            active_camera = None
+            for d in props.drawings:
+                if not (d.is_drawing and d.is_selected):
+                    continue
+                selected_drawing = tool.Ifc.get().by_id(d.ifc_definition_id)
+                # Importing the camera (if missing) ensures the drawing's
+                # collection exists so the annotations get collected into it.
+                if not (camera := tool.Ifc.get_object(selected_drawing)):
+                    camera = tool.Drawing.import_drawing(selected_drawing)
+                group = tool.Drawing.get_drawing_group(selected_drawing)
+                tool.Drawing.import_annotations_in_group(group)
+
+                if active_camera is None:
+                    active_camera = camera
+                objs_to_select.append(camera)
+                if self.include_annotations_in_selection:
+                    for element in tool.Drawing.get_group_elements(group) or []:
+                        if element.is_a("IfcAnnotation") and element.ObjectType != "DRAWING":
+                            if annotation_obj := tool.Ifc.get_object(element):
+                                objs_to_select.append(annotation_obj)
+
+            # Select the checked drawings' objects, with the first drawing's camera as active.
+            bpy.ops.object.select_all(action="DESELECT")
+            for obj in objs_to_select:
+                obj.select_set(True)
+            if active_camera is not None:
+                context.view_layer.objects.active = active_camera
+            return {"FINISHED"}
+
         drawing = tool.Ifc.get().by_id(self.drawing)
         dprops = tool.Drawing.get_document_props()
 
@@ -2439,7 +2521,10 @@ class ActivateDrawing(bpy.types.Operator, ActivateDrawingBase):
     bl_description = (
         "Activates the selected drawing view.\n\n"
         + "ALT+CLICK to keep the viewport position.\n\n"
-        + "SHIFT+CLICK to load a quick preview of the drawing view"
+        + "SHIFT+CLICK to load a quick preview of the drawing view.\n\n"
+        + "SHIFT+CTRL+CLICK to load the annotations of all selected drawings without switching views, "
+        + "then select their cameras (the first selected drawing's camera becomes active).\n\n"
+        + "SHIFT+CTRL+ALT+CLICK to do the same but also select the annotations, not just the cameras"
     )
 
 
@@ -3501,7 +3586,7 @@ class EditSheet(bpy.types.Operator, tool.Ifc.Operator):
         if sheet.is_a("IfcDocumentInformation"):
             self.document_type = "SHEET"
             self.name = sheet.Name
-            self.identification = sheet.DocumentId if tool.Ifc.get_schema() == "IFC2X3" else sheet.Identification
+            self.identification = tool.Document.get_document_information_id(sheet)
         elif sheet.is_a("IfcDocumentReference") and tool.Drawing.get_reference_description(sheet) == "TITLEBLOCK":
             self.document_type = "TITLEBLOCK"
         else:

src/bonsai/bonsai/bim/module/drawing/prop.py

@@ -604,6 +604,7 @@ class BIMCameraProperties(PropertyGroup):
         return tool.Blender.get_active_uilist_element(dprops.drawing_styles, self.active_drawing_style_index)
 
     # For now, this JSON dump are all the parameters that determine a camera's "Block representation"
+    # Perspective camera shift is stored in EPset_Drawing and intentionally excluded here.
     # By checking this, you will know whether or not the camera IFC representation needs to be refreshed
     def update_representation(self, matrix_world: Matrix) -> bool:
         """Update ``representation`` based on current camera properties and the provided world matrix.

src/bonsai/bonsai/bim/module/drawing/svgwriter.py

@@ -903,12 +903,8 @@ class SvgWriter:
                     continue
                 sheet = tool.Drawing.get_reference_document(sheet_reference)
                 if sheet:
-                    if tool.Ifc.get_schema() == "IFC2X3":
-                        reference_id = sheet_reference.ItemReference or "-"
-                        sheet_id = sheet.DocumentId or "-"
-                    else:
-                        reference_id = sheet_reference.Identification or "-"
-                        sheet_id = sheet.Identification or "-"
+                    reference_id = tool.Document.get_external_reference_id(sheet_reference) or "-"
+                    sheet_id = tool.Document.get_document_information_id(sheet) or "-"
                     return (reference_id, sheet_id)
                 break
         return ("-", "-")

src/bonsai/bonsai/bim/module/drawing/ui.py

@@ -99,6 +99,10 @@ class BIM_PT_camera(Panel):
         if props.target_view == "MODEL_VIEW":
             row = self.layout.row()
             row.prop(props, "camera_type")
+            if props.camera_type == "PERSP":
+                row = self.layout.row(align=True)
+                row.prop(camera_data, "shift_x", text="Camera Shift X/Y:")
+                row.prop(camera_data, "shift_y", text="")
 
         row = self.layout.row()
         row.prop(props, "linework_mode")

src/bonsai/bonsai/bim/module/geometry/decorator.py

@@ -16,8 +16,6 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
-from collections.abc import Sequence
-
 import blf
 import bpy
 import gpu
@@ -25,15 +23,16 @@ import ifcopenshell
 import numpy as np
 from bpy.types import SpaceView3D
 from bpy_extras.view3d_utils import location_3d_to_region_2d
-from gpu_extras.batch import batch_for_shader
 from mathutils import Matrix, Vector
 
 import bonsai.tool as tool
 
 
-class ItemDecorator:
-    is_installed = False
-    handlers = []
+class ItemDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_text", "POST_PIXEL"),
+        ("draw", "POST_VIEW"),
+    )
     objs: dict[str, dict[str, list]]
     obj_is_selected: dict[str, bool]
     obj_is_boolean: dict[str, list[ifcopenshell.entity_instance]]
@@ -119,23 +118,6 @@ class ItemDecorator:
             "special_edges": special_edges,
         }
 
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
-
     def draw_text(self, context):
         self.addon_prefs = tool.Blender.get_addon_preferences()
         selected_elements_color = self.addon_prefs.decorator_color_selected
@@ -163,11 +145,6 @@ class ItemDecorator:
         blf.disable(font_id, blf.SHADOW)
 
     def draw(self, context: bpy.types.Context) -> None:
-        def transparent_color(color: Sequence[float], alpha: float = 0.05) -> list[float]:
-            color = [i for i in color]
-            color[3] = alpha
-            return color
-
         self.addon_prefs = tool.Blender.get_addon_preferences()
         selected_elements_color = self.addon_prefs.decorator_color_selected
         unselected_elements_color = self.addon_prefs.decorator_color_unselected
@@ -197,15 +174,33 @@ class ItemDecorator:
                     if context.mode != "OBJECT":
                         continue
                     self.draw_batch("LINES", data["verts"], selected_elements_color, data["edges"])
-                    self.draw_batch("TRIS", data["verts"], transparent_color(selected_elements_color), data["tris"])
+                    self.draw_batch(
+                        "TRIS",
+                        data["verts"],
+                        tool.Blender.transparent_color(selected_elements_color, alpha=0.05),
+                        data["tris"],
+                    )
                     self.draw_batch("LINES", data["special_verts"], selected_elements_color, data["special_edges"])
                 elif self.obj_is_boolean[obj_name]:
                     self.draw_batch("LINES", data["verts"], special_elements_color, data["edges"])
-                    self.draw_batch("TRIS", data["verts"], transparent_color(special_elements_color), data["tris"])
+                    self.draw_batch(
+                        "TRIS",
+                        data["verts"],
+                        tool.Blender.transparent_color(special_elements_color, alpha=0.05),
+                        data["tris"],
+                    )
                     self.draw_batch("LINES", data["special_verts"], special_elements_color, data["special_edges"])
                 else:
                     self.draw_batch(
-                        "LINES", data["verts"], transparent_color(unselected_elements_color, alpha=0.2), data["edges"]
+                        "LINES",
+                        data["verts"],
+                        tool.Blender.transparent_color(unselected_elements_color, alpha=0.2),
+                        data["edges"],
+                    )
+                    self.draw_batch(
+                        "TRIS",
+                        data["verts"],
+                        tool.Blender.transparent_color(special_elements_color, alpha=0.05),
+                        data["tris"],
                     )
-                    self.draw_batch("TRIS", data["verts"], transparent_color(special_elements_color), data["tris"])
                     self.draw_batch("LINES", data["special_verts"], special_elements_color, data["special_edges"])

src/bonsai/bonsai/bim/module/geometry/operator.py

@@ -546,6 +546,13 @@ class UpdateRepresentation(bpy.types.Operator, tool.Ifc.Operator):
         objs = [bpy.data.objects[obj_name]] if obj_name else context.selected_objects
         self.file = tool.Ifc.get()
 
+        # Tessellated face sets (IfcTriangulatedFaceSet/IfcPolygonalFaceSet) were
+        # introduced in IFC4 and do not exist in IFC2X3. Catch this early so we
+        # don't silently fall back to a faceted brep after stripping materials.
+        if self.ifc_representation_class == "IfcTessellatedFaceSet" and self.file.schema == "IFC2X3":
+            self.report({"ERROR"}, "Tessellated face sets are not supported in IFC2X3.")
+            return {"CANCELLED"}
+
         for obj in objs:
             # TODO: write unit tests to see how this bulk operation handles
             # contradictory ifc_representation_class values and when
@@ -883,6 +890,16 @@ class OverrideDelete(bpy.types.Operator):
         # Track aggregates before deleting their parts
         aggregates_to_check = self.track_aggregates(objects_to_remove)
 
+        # Snapshot the set of IFC entity ids being deleted in this batch so the
+        # connection-rel cascade inside `delete_ifc_object` can suppress
+        # partner-side regenerate when the partner is also about to vanish.
+        batch_being_deleted_ids: set[int] = set()
+        for obj in objects_to_remove:
+            if not tool.Blender.is_valid_data_block(obj):
+                continue
+            if (entity := tool.Ifc.get_entity(obj)) is not None:
+                batch_being_deleted_ids.add(entity.id())
+
         clear_active_object = True
 
         for i, obj in enumerate(objects_to_remove, 1):
@@ -924,7 +941,7 @@ class OverrideDelete(bpy.types.Operator):
                 if tool.Drawing.is_auto_annotation(element):
                     self.report({"INFO"}, "References cannot be deleted. Exclude the referenced element instead.")
                     continue
-                tool.Geometry.delete_ifc_object(obj)
+                tool.Geometry.delete_ifc_object(obj, batch_being_deleted_ids=batch_being_deleted_ids)
             elif tool.Geometry.is_representation_item(obj):
                 tool.Geometry.delete_ifc_item(obj)
             else:
@@ -1023,7 +1040,10 @@ class OverrideDelete(bpy.types.Operator):
             pset = ifcopenshell.util.element.get_pset(element, "BBIM_Array")
             if not pset:
                 continue
-            array_parents.add(ifc_file.by_guid(pset["Parent"]))
+            try:
+                array_parents.add(ifc_file.by_guid(pset["Parent"]))
+            except RuntimeError:
+                continue
 
         for array_parent in array_parents:
             array_parent_obj = tool.Ifc.get_object(array_parent)
@@ -3166,7 +3186,7 @@ class EnableEditingRepresentationItems(bpy.types.Operator, tool.Ifc.Operator):
                 product_reps = element.RepresentationMaps
             item_aspect = {}
             for product_rep in product_reps:
-                for aspect in product_rep.HasShapeAspects:
+                for aspect in getattr(product_rep, "HasShapeAspects", ()):
                     for aspect_rep in aspect.ShapeRepresentations:
                         if aspect_rep.ContextOfItems != representation.ContextOfItems:
                             continue

src/bonsai/bonsai/bim/module/geometry/ui.py

@@ -17,9 +17,9 @@
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
+import ifcopenshell.util.unit
 from bpy.types import Menu, Panel, UIList
 
-import ifcopenshell.util.unit
 import bonsai.bim
 import bonsai.tool as tool
 from bonsai.bim.helper import prop_with_search

src/bonsai/bonsai/bim/module/georeference/decorator.py

@@ -21,7 +21,6 @@ from math import radians
 import blf
 import gpu
 import ifcopenshell.util.geolocation
-from bpy.types import SpaceView3D
 from bpy_extras.view3d_utils import location_3d_to_region_2d
 from gpu_extras.batch import batch_for_shader
 from mathutils import Matrix, Vector
@@ -30,27 +29,11 @@ import bonsai.tool as tool
 from bonsai.bim.module.georeference.data import GeoreferenceData
 
 
-class GeoreferenceDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_text, (context,), "WINDOW", "POST_PIXEL"))
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_geometry, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
+class GeoreferenceDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_text", "POST_PIXEL"),
+        ("draw_geometry", "POST_VIEW"),
+    )
 
     def draw_batch(self, shader_type, content_pos, color, indices=None, should_scale=True):
         if not tool.Blender.validate_shader_batch_data(content_pos, indices):
@@ -197,6 +180,10 @@ class GeoreferenceDecorator:
         decorator_color_error = self.addon_prefs.decorator_color_error
 
         gpu.state.blend_set("ALPHA")
+        # The georef gizmo is a coordinate-system overlay: it must communicate
+        # orientation regardless of model contents, so depth testing is bypassed.
+        original_depth_test = gpu.state.depth_test_get()
+        gpu.state.depth_test_set("ALWAYS")
 
         self.line_shader = gpu.shader.from_builtin("POLYLINE_UNIFORM_COLOR")
         self.line_shader.bind()  # required to be able to change uniforms of the shader
@@ -335,6 +322,8 @@ class GeoreferenceDecorator:
                 self.draw_batch("LINES", verts, decorator_color_special, edges)
                 self.draw_dashed_line(location * 3, location * 6, decorator_color_error)
 
+        gpu.state.depth_test_set(original_depth_test)
+
     def draw_dashed_line(self, start, end, colour, should_scale=True):
         direction = (end - start).normalized()
         distance = (end - start).length

src/bonsai/bonsai/bim/module/library/data.py

@@ -103,9 +103,7 @@ class LibraryReferencesData:
                 results.append(
                     {
                         "id": library.id(),
-                        "identification": (
-                            library.ItemReference if tool.Ifc.get_schema() == "IFC2X3" else library.Identification
-                        ),
+                        "identification": tool.Document.get_external_reference_id(library),
                         "name": library.Name or "Unnamed",
                     }
                 )

src/bonsai/bonsai/bim/module/light/decorator.py

@@ -20,44 +20,18 @@
 import blf
 import bpy
 import gpu
-from bpy.types import SpaceView3D
 from bpy_extras.view3d_utils import location_3d_to_region_2d
-from gpu_extras.batch import batch_for_shader
 from mathutils import Matrix, Vector
 
 import bonsai.tool as tool
 from bonsai.bim.module.light.data import SolarData
 
 
-class SolarDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_text, (context,), "WINDOW", "POST_PIXEL"))
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_geometry, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
+class SolarDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_text", "POST_PIXEL"),
+        ("draw_geometry", "POST_VIEW"),
+    )
 
     def draw_text(self, context: bpy.types.Context) -> None:
         self.addon_prefs = tool.Blender.get_addon_preferences()

src/bonsai/bonsai/bim/module/misc/operator.py

@@ -418,6 +418,13 @@ class ImportQuickFavorites(bpy.types.Operator):
     bl_description = "Import operators from Blender's Quick Favorites menu, including their configured properties"
     bl_options = {"REGISTER", "UNDO"}
 
+    @classmethod
+    def poll(cls, context):
+        if bpy.app.version[:2] not in tool.Misc.QuickFavorites.OFFSET_USER_MENUS:
+            cls.poll_message_set(f"Blender version {bpy.app.version_string} is not supported.")
+            return False
+        return True
+
     def execute(self, context) -> set["rna_enums.OperatorReturnItems"]:
         props = tool.Misc.get_misc_props()
         props.quick_favorites.clear()

src/bonsai/bonsai/bim/module/model/__init__.py

@@ -27,12 +27,14 @@ import bonsai.tool as tool
 from . import (
     array,
     covering,
+    decorator,
     door,
     external,
     grid,
     handler,
     host_add_opening_gizmo,
     mep,
+    mep_bend_preview,
     opening,
     product,
     profile,
@@ -84,6 +86,7 @@ classes = (
     product.SetActiveType,
     workspace.Hotkey,
     workspace.BIM_MT_add_representation_item,
+    wall.AddPerpendicularWall,
     wall.AddWallsFromSlab,
     wall.AlignWall,
     wall.CancelEditingWall,
@@ -108,6 +111,9 @@ classes = (
     wall.GizmoWallFilletPreview,
     wall.GizmoWallFilletReedit,
     wall.GizmoWallFilletToggleOpenings,
+    wall.GizmoPairDisconnect,
+    wall.GizmoSlabEdition,
+    wall.GizmoSlabUnjoinWalls,
     wall.GizmoWallJoinIntersection,
     wall.GizmoWallLinkToggle,
     wall.GizmoWallUnjoinSingle,
@@ -118,7 +124,7 @@ classes = (
     wall.RotateWall90,
     wall.SplitWall,
     wall.SplitWallAtCursor,
-    wall.UnjoinWallPathConnection,
+    wall.DisconnectElements,
     wall.UnjoinWalls,
     wall.EnableWallFilletPreview,
     wall.FinishWallFilletPreview,
@@ -152,11 +158,14 @@ classes = (
     slab.DisableEditingExtrusionProfile,
     slab.DisableEditingSketchExtrusionProfile,
     slab.AddSlabFromWall,
+    slab.CancelEditingSlab,
     slab.DrawPolylineSlab,
     slab.EditExtrusionProfile,
     slab.EditSketchExtrusionProfile,
     slab.EnableEditingExtrusionProfile,
     slab.EnableEditingSketchExtrusionProfile,
+    slab.EnableEditingSlab,
+    slab.FinishEditingSlab,
     slab.RecalculateSlab,
     slab.ResetVertex,
     slab.SetArcIndex,
@@ -183,11 +192,16 @@ classes = (
     prop.BIMDoorProperties,
     prop.BIMRailingProperties,
     prop.BIMRoofProperties,
+    prop.BIMSlabProperties,
     prop.BIMWallProperties,
+    prop.BIMPipeSegmentProperties,
+    prop.BIMDuctSegmentProperties,
     prop.BIMPolylineProperties,
     prop.BIMExternalParametricGeometryProperties,
+    prop.BIMBendPreviewProperties,
     prop.BIMWallFilletPreviewProperties,
     prop.BIMPreviewProperties,
+    prop.BIMParametricEditDialogPrefs,
     ui.BIM_PT_array,
     ui.BIM_PT_stair,
     ui.BIM_PT_wall,
@@ -240,9 +254,13 @@ classes = (
     railing.CopyRailingParameters,
     railing.AddRailing,
     railing.CancelEditingRailing,
+    railing.CycleRailingType,
     railing.FinishEditingRailing,
+    railing.PickRailingTerminalType,
     railing.FlipRailingPathOrder,
     railing.EnableEditingRailing,
+    railing.GizmoRailingSchematic,
+    railing.ToggleRailingUseManualSupports,
     railing.CancelEditingRailingPath,
     railing.FinishEditingRailingPath,
     railing.EnableEditingRailingPath,
@@ -263,6 +281,27 @@ classes = (
     mep.MEPAddObstruction,
     mep.MEPAddTransition,
     mep.MEPAddBend,
+    mep.MEPRemoveTerminalFitting,
+    mep.SelectMEPPathMembers,
+    mep.MEPJoinSegments,
+    mep_bend_preview.EnableBendPreview,
+    mep_bend_preview.FinishBendPreview,
+    mep_bend_preview.CancelBendPreview,
+    mep_bend_preview.EnableBendPreviewFromBend,
+    mep_bend_preview.GizmoBendPreview,
+    mep.EnableEditingPipeSegment,
+    mep.FinishEditingPipeSegment,
+    mep.CancelEditingPipeSegment,
+    mep.EnableEditingDuctSegment,
+    mep.FinishEditingDuctSegment,
+    mep.CancelEditingDuctSegment,
+    mep.ExtendPipeSegmentToCursor,
+    mep.ExtendDuctSegmentToCursor,
+    mep.SplitPipeSegmentAtCursor,
+    mep.SplitDuctSegmentAtCursor,
+    mep.GizmoPipeSegmentEdition,
+    mep.GizmoDuctSegmentEdition,
+    mep.GizmoMEPActions,
     external.ApplyExternalParametricGeometry,
 )
 
@@ -322,6 +361,9 @@ def register():
         type=prop.BIMExternalParametricGeometryProperties
     )
     bpy.types.Scene.BIMPreviewProperties = bpy.props.PointerProperty(type=prop.BIMPreviewProperties)
+    bpy.types.WindowManager.BIMParametricEditDialogPrefs = bpy.props.PointerProperty(
+        type=prop.BIMParametricEditDialogPrefs
+    )
 
     bpy.types.VIEW3D_MT_add.prepend(ui.add_menu)
     bpy.app.handlers.load_post.append(handler.load_post)
@@ -336,6 +378,11 @@ def unregister():
     # half-unloaded module state.
     opening.DecorationsHandler.uninstall()
 
+    # Network path overlays attach SpaceView3D draw handlers on toggle;
+    # uninstall here so addon disable / Blender shutdown doesn't leak them.
+    decorator.MEPSystemPathDecorator.uninstall()
+    decorator.WallSystemPathDecorator.uninstall()
+
     if not bpy.app.background:
         for tool_data in reversed(tools):
             bpy.utils.unregister_tool(tool_data.tool)
@@ -347,6 +394,7 @@ def unregister():
     tool.Parametric.unregister_object_properties()
     del bpy.types.Object.BIMExternalParametricGeometryProperties
     del bpy.types.Scene.BIMPreviewProperties
+    del bpy.types.WindowManager.BIMParametricEditDialogPrefs
 
     bpy.app.handlers.load_post.remove(handler.load_post)
     bpy.types.VIEW3D_MT_add.remove(ui.add_menu)

src/bonsai/bonsai/bim/module/model/array.py

@@ -15,6 +15,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was modified with the assistance of an AI coding tool.
 
 import json
 from typing import ClassVar
@@ -327,6 +329,7 @@ class _ArrayEditMixin(ParametricEditMixinBase):
         # Unhide the (possibly newly-regenerated) children so the user sees
         # the committed result. Mirrors the hide in ``_enable_one``.
         cls._set_children_visibility(element, hidden=False)
+        tool.Array.select_only_parent(obj, context)
 
     @classmethod
     def _cancel_one(cls, obj: bpy.types.Object) -> None:
@@ -419,18 +422,28 @@ class RegenerateArray(bpy.types.Operator, tool.Ifc.Operator):
         pset = ifcopenshell.util.element.get_pset(parent_element, "BBIM_Array")
         arrays = json.loads(pset["Data"])
         pset = tool.Ifc.get().by_id(pset["id"])
-        for array in arrays:
-            for child in set(array["children"]):
-                if child_obj := tool.Ifc.get_object(tool.Ifc.get().by_guid(child)):
-                    tool.Geometry.delete_ifc_object(child_obj)
-            array["children"].clear()
-        # Always operate on the parent — this operator can be invoked with
-        # either the parent OR any array child as active_object (the per-child
-        # gizmo group fires it from a child selection). Using ``obj`` /
-        # ``element`` directly would feed a child to ``regenerate_array`` and
-        # constrain children against a sibling, silently corrupting the array.
-        tool.Model.regenerate_array(parent, arrays)
-        tool.Array.constrain_children_to_parent(parent_element)
+        # Coalesce host recuts across the child-delete loop, the regenerate,
+        # and the per-child opening mirror: each fans out its own host body
+        # recut without the batch wrapper.
+        with tool.Geometry.batch_host_recut():
+            for array in arrays:
+                for child in set(array["children"]):
+                    try:
+                        child_element = tool.Ifc.get().by_guid(child)
+                    except RuntimeError:
+                        continue
+                    if child_obj := tool.Ifc.get_object(child_element):
+                        tool.Geometry.delete_ifc_object(child_obj)
+                array["children"].clear()
+            # Always operate on the parent — this operator can be invoked with
+            # either the parent OR any array child as active_object (the per-child
+            # gizmo group fires it from a child selection). Using ``obj`` /
+            # ``element`` directly would feed a child to ``regenerate_array`` and
+            # constrain children against a sibling, silently corrupting the array.
+            tool.Model.regenerate_array(parent, arrays)
+            tool.Array.constrain_children_to_parent(parent_element)
+
+        tool.Array.select_only_parent(parent, context)
 
 
 class RemoveArray(bpy.types.Operator, tool.Ifc.Operator):
@@ -465,23 +478,24 @@ class RemoveArray(bpy.types.Operator, tool.Ifc.Operator):
         except:
             return {"FINISHED"}
 
-        if self.keep_objs:
-            tool.Array.bake_children_transform(element, self.item)
-            tool.Array.set_children_lock_state(element, self.item, False)
+        with tool.Geometry.batch_host_recut():
+            if self.keep_objs:
+                tool.Array.bake_children_transform(element, self.item)
+                tool.Array.set_children_lock_state(element, self.item, False)
 
-        if not self.keep_objs:
-            data[self.item]["count"] = 1
-        tool.Array.remove_constraints(parent_element)
-        tool.Model.regenerate_array(parent, data, array_layers_to_apply=[self.item] if self.keep_objs else [])
+            if not self.keep_objs:
+                data[self.item]["count"] = 1
+            tool.Array.remove_constraints(parent_element)
+            tool.Model.regenerate_array(parent, data, array_layers_to_apply=[self.item] if self.keep_objs else [])
 
-        pset = tool.Pset.get_element_pset(element, "BBIM_Array")
-        if len(data) == 1:
-            ifcopenshell.api.pset.remove_pset(tool.Ifc.get(), product=element, pset=pset)
-        else:
-            del data[self.item]
-            data = tool.Ifc.get().createIfcText(json.dumps(data))
-            ifcopenshell.api.pset.edit_pset(tool.Ifc.get(), pset=pset, properties={"Data": data})
-            tool.Array.constrain_children_to_parent(element)
+            pset = tool.Pset.get_element_pset(element, "BBIM_Array")
+            if len(data) == 1:
+                ifcopenshell.api.pset.remove_pset(tool.Ifc.get(), product=element, pset=pset)
+            else:
+                del data[self.item]
+                data = tool.Ifc.get().createIfcText(json.dumps(data))
+                ifcopenshell.api.pset.edit_pset(tool.Ifc.get(), pset=pset, properties={"Data": data})
+                tool.Array.constrain_children_to_parent(element)
 
 
 class SelectArrayParent(bpy.types.Operator):
@@ -881,6 +895,36 @@ class EnableEditingParametric(bpy.types.Operator):
         default="",
         description="Operator bl_idname to invoke (e.g., 'bim.enable_editing_door').",
     )
+    sibling_count: bpy.props.IntProperty(default=0, options={"HIDDEN"})
+
+    @staticmethod
+    def should_show_shared_rep_dialog(*, suppress: bool, has_entity: bool, sibling_count: int) -> bool:
+        """Pure decision for the pre-edit warning. Returns ``True`` only when the
+        edit will silently mutate other elements' geometry AND the user has not
+        opted out of the warning for this session."""
+        if suppress or not has_entity:
+            return False
+        return sibling_count > 0
+
+    def invoke(self, context, event):
+        prefs = getattr(context.window_manager, "BIMParametricEditDialogPrefs", None)
+        suppress = bool(prefs and prefs.suppress_shared_rep_warning)
+        obj = context.active_object
+        element = tool.Ifc.get_entity(obj) if obj else None
+        self.sibling_count = tool.Model.get_sibling_occurrence_count(element) if element is not None else 0
+        if self.should_show_shared_rep_dialog(
+            suppress=suppress, has_entity=element is not None, sibling_count=self.sibling_count
+        ):
+            return context.window_manager.invoke_props_dialog(self, width=400)
+        return self.execute(context)
+
+    def draw(self, context):
+        layout = self.layout
+        layout.label(text="Shared geometry", icon="ERROR")
+        layout.label(text=f"Geometry is shared with {self.sibling_count} other element(s).")
+        layout.label(text="Edits will affect them too.")
+        prefs = context.window_manager.BIMParametricEditDialogPrefs
+        layout.prop(prefs, "suppress_shared_rep_warning", text="Don't show this again for this session")
 
     def execute(self, context):
         # Malformed ``feature_enable_op`` (missing dot) would otherwise crash

src/bonsai/bonsai/bim/module/model/data.py

@@ -51,6 +51,10 @@ class AuthoringData:
 
     @classmethod
     def load(cls, ifc_element_type: Optional[str] = None):
+        # ``is_loaded`` is set first as a recursion guard: one of the data
+        # computations evaluates a PropertyGroup enum's ``items`` callback,
+        # which re-enters this method. Without the guard, load recurses to
+        # RecursionError.
         cls.is_loaded = True
         cls.props = tool.Model.get_model_props()
         cls.data["default_container"] = cls.default_container()

src/bonsai/bonsai/bim/module/model/host_add_opening_gizmo.py

@@ -33,6 +33,7 @@ from mathutils import Vector
 
 import bonsai.tool as tool
 from bonsai.bim.module.drawing import gizmos as gizmo
+from bonsai.bim.module.model.opening import is_filling_supported
 from bonsai.bim.module.model.wall import (
     _get_wall_geom_cached,
     _wall_camera_facing_icon_y,
@@ -52,6 +53,20 @@ def is_supported_host(element) -> bool:
     return tool.Parametric.is_path_connectable_wall(element) or element.is_a("IfcSlab") or element.is_a("IfcRoof")
 
 
+def is_supported_filling_or_opening(element) -> bool:
+    """Total predicate for the add-opening gizmo poll. ``None`` (raw Blender
+    mesh) is accepted because the operator converts unclassified meshes
+    into ``IfcOpeningElement`` instances. ``IfcOpeningElement`` is accepted
+    because reassigning an existing opening to a new host is a legal path
+    through the operator. Otherwise defer to the generator's own
+    supported-filling predicate."""
+    if element is None:
+        return True
+    if element.is_a("IfcOpeningElement"):
+        return True
+    return is_filling_supported(element)
+
+
 def _resolve_active_host(context: bpy.types.Context, n_selected: int):
     """Shared poll prologue: gizmo gate + selection cardinality + active-in-
     selected + IFC entity lookup + supported-host predicate. Returns the
@@ -72,12 +87,14 @@ def _resolve_active_host(context: bpy.types.Context, n_selected: int):
 
 
 class GizmoHostAddOpening(bpy.types.GizmoGroup, _WallGeomCachedBillboardingMixin):
-    """Activates when a host element (wall / slab / roof) is the active object
-    and exactly one other selected object is *not* itself a host.
+    """Activates when exactly two objects are selected and one is a fillable
+    host (wall / slab / roof) while the other is a valid filling (door /
+    window / existing opening, or a plain Blender mesh).
 
-    Renders a single ``VIEW3D_GT_add_opening`` icon at the void object's
-    projected location on the host. A click dispatches ``bim.add_opening``,
-    which handles any element exposing the ``HasOpenings`` inverse.
+    Selection-order independent: the host role is identified by class, not
+    by active state. The "+" icon anchors on the host's surface regardless
+    of which object was clicked first. The dispatched ``bim.add_opening``
+    operator also handles either order.
 
     Per-frame positioning keeps the icon facing the camera as the viewport
     orbits."""
@@ -90,22 +107,29 @@ class GizmoHostAddOpening(bpy.types.GizmoGroup, _WallGeomCachedBillboardingMixin
 
     @classmethod
     def poll(cls, context: bpy.types.Context) -> bool:
-        element = _resolve_active_host(context, n_selected=2)
-        if element is None:
+        if not _wall_gizmo_poll_gate(context):
             return False
-        # The operator itself filters on HasOpenings, but checking here keeps
-        # the icon from appearing on host classes that can't accept openings
-        # in the active IFC schema.
-        if not hasattr(element, "HasOpenings"):
+        selected = list(tool.Blender.get_selected_objects())
+        if len(selected) != 2:
             return False
         active = context.active_object
-        other = next(o for o in tool.Blender.get_selected_objects() if o is not active)
-        # Host + host pairings are claimed by host-specific gizmos (wall-join,
-        # extend-vertical, …) — suppress here so the add-opening icon never
-        # stacks on top of them.
-        if is_supported_host(tool.Ifc.get_entity(other)):
+        if active is None or active not in selected:
             return False
-        return True
+        a_element = tool.Ifc.get_entity(selected[0])
+        b_element = tool.Ifc.get_entity(selected[1])
+        return cls._is_apply_opening_pair(a_element, b_element) or cls._is_apply_opening_pair(b_element, a_element)
+
+    @staticmethod
+    def _is_apply_opening_pair(host_element, filling_element) -> bool:
+        """``host_element`` qualifies as a fillable host AND ``filling_element``
+        qualifies as a filling. Used twice with the operands swapped so the
+        gizmo polls true regardless of which of the two selected objects is
+        active."""
+        if not is_supported_host(host_element):
+            return False
+        if not hasattr(host_element, "HasOpenings"):
+            return False
+        return is_supported_filling_or_opening(filling_element)
 
     def setup(self, context: bpy.types.Context) -> None:
         default_color, highlight_color = self.get_decoration_colors()
@@ -114,18 +138,20 @@ class GizmoHostAddOpening(bpy.types.GizmoGroup, _WallGeomCachedBillboardingMixin
         )
 
     def position_gizmos(self, context: bpy.types.Context) -> None:
-        host_obj = context.active_object
-        if not host_obj:
+        selected = list(tool.Blender.get_selected_objects())
+        if len(selected) != 2:
             return
-        selected = tool.Blender.get_selected_objects()
-        other = next((o for o in selected if o is not host_obj), None)
-        if not other:
-            return
-        element = tool.Ifc.get_entity(host_obj)
-        if not element:
+        a, b = selected[0], selected[1]
+        a_element = tool.Ifc.get_entity(a)
+        b_element = tool.Ifc.get_entity(b)
+        if is_supported_host(a_element):
+            host_obj, host_element, other = a, a_element, b
+        elif is_supported_host(b_element):
+            host_obj, host_element, other = b, b_element, a
+        else:
             return
 
-        if tool.Parametric.is_path_connectable_wall(element):
+        if tool.Parametric.is_path_connectable_wall(host_element):
             world_pos = wall_anchor(context, self, host_obj, other)
         else:
             world_pos = layer3_anchor(host_obj, other)

src/bonsai/bonsai/bim/module/model/mep_bend_preview.py

@@ -0,0 +1,444 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Bend-preview lifecycle for MEP segment joins.
+
+Holds the four lifecycle operators (Enable / Finish / Cancel /
+EnableFromBend) and the ``GizmoBendPreview`` group that surfaces the
+tunable dimensions and validate/cancel icons during preview. Draft state
+lives at ``Scene.BIMPreviewProperties.bend`` per CLAUDE.md §2.9 (Scene
+for cross-element previews).
+
+The geometry math (``compute_bend_preview_polylines``,
+``_bend_profile_cross_section``, ``_sweep_profile_along_polyline``)
+stays in ``mep.py`` because the commit operator ``MEPAddBend`` reuses
+it; this module imports the polyline helper for per-frame gizmo
+positioning. The GPU lines themselves are drawn by
+``decorator.BendPreviewDecorator``, kept in ``decorator.py`` with its
+sibling decorators."""
+
+from typing import ClassVar
+
+import bpy
+import ifcopenshell.util.element
+import ifcopenshell.util.unit
+from mathutils import Matrix, Vector
+
+import bonsai.tool as tool
+from bonsai.bim.module.drawing import gizmos as gizmo
+from bonsai.bim.module.model import preview_base
+from bonsai.bim.module.model.mep import (
+    _is_bend_fitting,
+    _n_mep_selected,
+    cached_compute_bend_preview_polylines,
+    segments_are_parallel,
+    validate_bend_preconditions,
+)
+
+
+class EnableBendPreview(bpy.types.Operator):
+    """Enter bend-preview mode for two selected MEP segments. Populates
+    scene.BIMPreviewProperties.bend with segment IFC ids and default
+    start_length / end_length / radius; no IFC mutation until finish."""
+
+    bl_idname = "bim.enable_bend_preview"
+    bl_label = "Enter Bend Preview"
+    bl_description = "Begin tuning bend parameters before committing the bend"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        if not _n_mep_selected(2):
+            cls.poll_message_set("Select exactly 2 MEP segments to bend.")
+            return False
+        return True
+
+    def execute(self, context):
+        selected = tool.Blender.get_selected_objects()
+        active = context.active_object
+        if active is None or active not in selected:
+            self.report({"ERROR"}, "Active object must be one of the selected MEP segments.")
+            return {"CANCELLED"}
+        other = next((o for o in selected if o is not active), None)
+        if other is None:
+            self.report({"ERROR"}, "Two MEP segments must be selected.")
+            return {"CANCELLED"}
+        active_element = tool.Ifc.get_entity(active)
+        other_element = tool.Ifc.get_entity(other)
+        if active_element is None or other_element is None:
+            self.report({"ERROR"}, "Both selected objects must be IFC elements.")
+            return {"CANCELLED"}
+        if segments_are_parallel(active, other):
+            self.report({"ERROR"}, "Bend preview is for non-parallel segments only.")
+            return {"CANCELLED"}
+
+        # Pre-check the same preconditions MEPAddBend enforces so the user
+        # sees the rejection here rather than after tuning a doomed preview.
+        precondition_error = validate_bend_preconditions(active_element, other_element)
+        if precondition_error is not None:
+            self.report({"ERROR"}, precondition_error)
+            return {"CANCELLED"}
+
+        preview_base.sync_uncommitted_moves([active, other])
+
+        props = preview_base.get_preview_props(context, "bend")
+        # Auto-cancel any prior preview so re-clicking join on a different
+        # pair doesn't silently commit the previous tuning.
+        if props is not None and props.is_active:
+            bpy.ops.bim.cancel_bend_preview()
+
+        props.start_segment_id = active_element.id()
+        props.end_segment_id = other_element.id()
+        props.start_length = 0.1
+        props.end_length = 0.1
+        props.radius = 0.2
+        props.is_active = True
+        return {"FINISHED"}
+
+
+class FinishBendPreview(bpy.types.Operator):
+    """Commit the previewed bend with the tuned parameters and exit preview.
+
+    Preview state survives a failed commit so the user can re-tune without
+    re-selecting."""
+
+    bl_idname = "bim.finish_bend_preview"
+    bl_label = "Apply Bend"
+    bl_description = "Commit the bend with the previewed parameters"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        return preview_base.commit_preview(
+            self,
+            context,
+            "bend",
+            "mep_add_bend",
+            ("start_segment_id", "end_segment_id", "start_length", "end_length", "radius", "editing_bend_id"),
+        )
+
+
+class CancelBendPreview(bpy.types.Operator):
+    """Exit bend preview without committing."""
+
+    bl_idname = "bim.cancel_bend_preview"
+    bl_label = "Cancel Bend"
+    bl_description = "Discard the previewed bend"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        if context.screen is None:
+            return {"CANCELLED"}
+        props = preview_base.get_preview_props(context, "bend")
+        if props is None or not props.is_active:
+            return {"CANCELLED"}
+        preview_base.clear_preview_state(props)
+        return {"FINISHED"}
+
+
+class EnableBendPreviewFromBend(bpy.types.Operator):
+    """Re-open the bend preview on an existing bend fitting.
+
+    Resolves the two connected segments via the bend's ports +
+    ``IfcRelConnectsPorts``, reads parametric values back from the bend's
+    ``BBIM_Fitting`` pset, and flags the preview so committing replaces
+    the existing bend in place."""
+
+    bl_idname = "bim.enable_bend_preview_from_bend"
+    bl_label = "Edit Bend"
+    bl_description = "Re-open the bend preview to retune an existing bend"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        active = context.active_object
+        if active is None:
+            cls.poll_message_set("No active object.")
+            return False
+        element = tool.Ifc.get_entity(active)
+        if element is None or not _is_bend_fitting(element):
+            cls.poll_message_set("Active object must be a bend fitting.")
+            return False
+        return True
+
+    def execute(self, context):
+        active = context.active_object
+        bend_element = tool.Ifc.get_entity(active)
+        if bend_element is None or not _is_bend_fitting(bend_element):
+            self.report({"ERROR"}, "Active object is not a bend fitting.")
+            return {"CANCELLED"}
+
+        connected_segments: list = []
+        for port in tool.System.get_ports(bend_element):
+            connected_port = tool.System.get_connected_port(port)
+            if connected_port is None:
+                continue
+            related = tool.System.get_port_relating_element(connected_port)
+            if related is not None and related.is_a("IfcFlowSegment") and related not in connected_segments:
+                connected_segments.append(related)
+
+        if len(connected_segments) != 2:
+            self.report(
+                {"ERROR"},
+                f"Bend has {len(connected_segments)} connected segments; need exactly 2 to re-edit.",
+            )
+            return {"CANCELLED"}
+
+        # Read parametric values from the bend type's BBIM_Fitting pset. The
+        # type carries the canonical parameters; querying the occurrence
+        # would force a get_type round-trip and miss user-edited types.
+        bend_type = ifcopenshell.util.element.get_type(bend_element)
+        if bend_type is None:
+            self.report({"ERROR"}, "Bend fitting has no type to read parameters from.")
+            return {"CANCELLED"}
+        bend_type_obj = tool.Ifc.get_object(bend_type)
+        if bend_type_obj is None:
+            self.report({"ERROR"}, "Bend type has no Blender object — cannot read pset.")
+            return {"CANCELLED"}
+        bbim = tool.Model.get_modeling_bbim_pset_data(bend_type_obj, "BBIM_Fitting")
+        if bbim is None:
+            self.report({"ERROR"}, "Bend fitting has no BBIM_Fitting pset — not a parametric bend.")
+            return {"CANCELLED"}
+        data = bbim.get("data_dict", {})
+
+        props = preview_base.get_preview_props(context, "bend")
+        if props is not None and props.is_active:
+            bpy.ops.bim.cancel_bend_preview()
+
+        # Segment order is load-bearing: the bend's lateral sign and z-axis
+        # flip are derived from which segment is "start" vs "end". Re-edit
+        # must reuse the same pairing as the original create so the recreate
+        # lands at the same orientation.
+        start_segment, end_segment = connected_segments
+        props.start_segment_id = start_segment.id()
+        props.end_segment_id = end_segment.id()
+        # Pset values are in IFC native units; scene units come from si_conversion.
+        si_conversion = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
+        props.start_length = float(data.get("start_length", 0.1)) * si_conversion
+        props.end_length = float(data.get("end_length", 0.1)) * si_conversion
+        props.radius = float(data.get("radius", 0.2)) * si_conversion
+        props.editing_bend_id = bend_element.id()
+        props.is_active = True
+        return {"FINISHED"}
+
+
+def _bend_preview_segments(context):
+    """Resolve the two segment objects from the scene-level preview props.
+
+    Re-resolves by IFC id each frame so undo / file reload during preview
+    never dangles a stale bpy reference."""
+    props = context.scene.BIMPreviewProperties.bend
+    ifc_file = tool.Ifc.get()
+    if ifc_file is None or not props.is_active:
+        return None, None
+    try:
+        start_element = ifc_file.by_id(props.start_segment_id)
+        end_element = ifc_file.by_id(props.end_segment_id)
+    except Exception:
+        return None, None
+    start_obj = tool.Ifc.get_object(start_element) if start_element else None
+    end_obj = tool.Ifc.get_object(end_element) if end_element else None
+    return start_obj, end_obj
+
+
+def _gizmo_x_matrix(location: Vector, x_direction: Vector) -> Matrix:
+    """Build a 4x4 matrix placing a gizmo at ``location`` with its local +X
+    axis aligned to ``x_direction`` in world space. ``BIM_GT_gizmo_dimension``
+    draws + drags along local +X by convention."""
+    x = x_direction.normalized()
+    seed = Vector((0, 0, 1)) if abs(x.z) < 0.9 else Vector((1, 0, 0))
+    y = (seed - x * seed.dot(x)).normalized()
+    z = x.cross(y)
+    mat = Matrix.Identity(4)
+    mat[0][:3] = (x.x, y.x, z.x)
+    mat[1][:3] = (x.y, y.y, z.y)
+    mat[2][:3] = (x.z, y.z, z.z)
+    mat.translation = location
+    return mat
+
+
+class GizmoBendPreview(bpy.types.GizmoGroup):
+    """Interactive gizmo group for the bend preview flow.
+
+    Three dimension widgets drag start_length / end_length / radius; two
+    icon gizmos commit or cancel. When the geometry is degenerate the
+    dimensions and validate hide but cancel stays visible so the user
+    always has an exit."""
+
+    bl_idname = "OBJECT_GGT_bim_bend_preview"
+    bl_label = "Bend Preview Gizmos"
+    bl_space_type = "VIEW_3D"
+    bl_region_type = "WINDOW"
+    bl_options = {"3D", "PERSISTENT"}
+
+    ICON_SCALE: ClassVar[float] = 0.375
+    ICON_SPACING_X: ClassVar[float] = 0.4
+    ICON_Z_OFFSET: ClassVar[float] = 1.5
+
+    @classmethod
+    def poll(cls, context):
+        preview = getattr(context.scene, "BIMPreviewProperties", None)
+        props = preview.bend if preview is not None else None
+        if props is None or not props.is_active:
+            return False
+        if not tool.Blender.are_viewport_gizmos_enabled():
+            return False
+        ifc_file = tool.Ifc.get()
+        if ifc_file is None:
+            return False
+        try:
+            ifc_file.by_id(props.start_segment_id)
+            ifc_file.by_id(props.end_segment_id)
+        except (RuntimeError, KeyError):
+            return False
+        return True
+
+    def setup(self, context):
+        prefs = tool.Blender.get_addon_preferences()
+        default_color = tuple(prefs.decorations_colour[:3])
+        highlight_color = tuple(prefs.decorator_color_selected[:3])
+
+        _props = preview_base.make_props_callback("bend")
+
+        def setup_dimension(attr: str, prop_name: str, invert_delta: bool = False) -> bpy.types.Gizmo:
+            gz = self.gizmos.new("BIM_GT_gizmo_dimension")
+            gz.move_get_cb = preview_base.make_dim_getter(_props, attr)
+            gz.move_set_cb = preview_base.make_dim_setter(_props, attr)
+            gz.axis = Vector((1, 0, 0))
+            gz.invert_delta = invert_delta
+            gz.delta_scale = 1.0
+            gz.prop_name = prop_name
+            gz.gizmo_group = self
+            gz.color = default_color
+            gz.color_highlight = highlight_color
+            gz.alpha = 1.0
+            gz.use_draw_modal = True
+            gz.use_draw_scale = False
+            gz.text_offset_sign = 1
+            gz.text_alignment = gizmo.TextAlignment.CENTER
+            gz.show_start_arrow = False
+            gz.show_end_arrow = True
+            gz.show_extension_lines = False
+            gz.text_formatter = None
+            return gz
+
+        self.start_dim = setup_dimension("start_length", "Start Length")
+        self.end_dim = setup_dimension("end_length", "End Length")
+        self.radius_dim = setup_dimension("radius", "Radius")
+
+        from bonsai.bim.module.drawing.gizmos import BaseParametricGizmoGroup
+
+        self.validate_icon = self.gizmos.new("VIEW3D_GT_validate")
+        self.validate_icon.use_draw_scale = False
+        self.validate_icon.color = BaseParametricGizmoGroup.COLOR_GREEN
+        self.validate_icon.color_highlight = highlight_color
+        self.validate_icon.target_set_operator("bim.finish_bend_preview")
+
+        self.cancel_icon = self.gizmos.new("VIEW3D_GT_cancel")
+        self.cancel_icon.use_draw_scale = False
+        self.cancel_icon.color = BaseParametricGizmoGroup.COLOR_RED
+        self.cancel_icon.color_highlight = highlight_color
+        self.cancel_icon.target_set_operator("bim.cancel_bend_preview")
+
+    def refresh(self, context):
+        self._position_gizmos(context)
+
+    def draw_prepare(self, context):
+        self._position_gizmos(context)
+
+    def _position_gizmos(self, context):
+        """Place gizmos at the bend intersection using the current scene
+        props. Cancel stays visible on degenerate geometry so the user
+        always has an exit; the other widgets hide when there's no defined
+        tangent / arc to anchor them on."""
+        start_obj, end_obj = _bend_preview_segments(context)
+        if start_obj is None or end_obj is None:
+            for gz in (self.start_dim, self.end_dim, self.radius_dim, self.validate_icon, self.cancel_icon):
+                gz.hide = True
+            return
+
+        props = context.scene.BIMPreviewProperties.bend
+        preview = cached_compute_bend_preview_polylines(
+            start_obj, end_obj, props.start_length, props.end_length, props.radius
+        )
+        if not preview["valid"]:
+            for gz in (self.start_dim, self.end_dim, self.radius_dim, self.validate_icon):
+                gz.hide = True
+            self.cancel_icon.hide = False
+            axes = preview.get("invalid_axes") or []
+            if axes:
+                intersection_point = axes[0][1]
+                billboard_rot = gizmo.get_billboard_rotation(context)
+                anchor = intersection_point + Vector((0, 0, self.ICON_Z_OFFSET))
+                self.cancel_icon.matrix_basis = gizmo.billboarded_at(anchor, billboard_rot, scale=self.ICON_SCALE)
+            return
+
+        for gz in (self.start_dim, self.end_dim, self.radius_dim, self.validate_icon, self.cancel_icon):
+            gz.hide = False
+
+        leg_a_far, leg_a_end = preview["leg_a"]
+        leg_b_far, leg_b_end = preview["leg_b"]
+        toward_bend_a = (
+            (leg_a_end - leg_a_far).normalized() if (leg_a_end - leg_a_far).length > 1e-6 else Vector((0, 0, 1))
+        )
+        toward_bend_b = (
+            (leg_b_end - leg_b_far).normalized() if (leg_b_end - leg_b_far).length > 1e-6 else Vector((0, 0, 1))
+        )
+        leg_a_tangent = leg_a_end + toward_bend_a * props.start_length
+        leg_b_tangent = leg_b_end + toward_bend_b * props.end_length
+
+        # axis is set in world space every frame so the drag projection
+        # matches the visual regardless of either segment's matrix_world.
+        self.start_dim.matrix_basis = _gizmo_x_matrix(leg_a_tangent, -toward_bend_a)
+        self.start_dim.axis = -toward_bend_a
+        self.start_dim.set_dimension_length(props.start_length)
+        self.end_dim.matrix_basis = _gizmo_x_matrix(leg_b_tangent, -toward_bend_b)
+        self.end_dim.axis = -toward_bend_b
+        self.end_dim.set_dimension_length(props.end_length)
+
+        arc = preview["arc"]
+        if len(arc) >= 3:
+            mid = len(arc) // 2
+            chord_mid = (arc[0] + arc[-1]) * 0.5
+            toward_mid = arc[mid] - chord_mid
+            if toward_mid.length > 1e-6:
+                toward_mid = toward_mid.normalized()
+                half_chord = (arc[-1] - arc[0]).length * 0.5
+                center_dist = max(0.0, props.radius * props.radius - half_chord * half_chord) ** 0.5
+                arc_center = chord_mid - toward_mid * center_dist
+                radial_out = arc[mid] - arc_center
+                if radial_out.length > 1e-6:
+                    radial_out.normalize()
+                    inward = -radial_out
+                    self.radius_dim.matrix_basis = _gizmo_x_matrix(arc[mid], inward)
+                    self.radius_dim.axis = inward
+                    self.radius_dim.set_dimension_length(props.radius)
+                else:
+                    self.radius_dim.hide = True
+            else:
+                self.radius_dim.hide = True
+        else:
+            self.radius_dim.hide = True
+
+        billboard_rot = gizmo.get_billboard_rotation(context)
+        anchor_base = arc[len(arc) // 2] if arc else (leg_a_end + leg_b_end) * 0.5
+        anchor = anchor_base + Vector((0, 0, self.ICON_Z_OFFSET))
+        offset_x = billboard_rot @ Vector((self.ICON_SPACING_X, 0.0, 0.0))
+        self.validate_icon.matrix_basis = gizmo.billboarded_at(anchor, billboard_rot, scale=self.ICON_SCALE)
+        self.cancel_icon.matrix_basis = gizmo.billboarded_at(anchor + offset_x, billboard_rot, scale=self.ICON_SCALE)

src/bonsai/bonsai/bim/module/model/opening.py

@@ -15,6 +15,8 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was modified with the assistance of an AI coding tool.
 
 from collections.abc import Sequence
 from math import radians
@@ -207,6 +209,21 @@ def _get_cached_world_draw_data(
 # handle each call), so they stay drawable across frames.
 _batch_cache: dict[tuple[int, str], tuple[int, "gpu.types.GPUBatch"]] = {}
 
+# CAD hidden-line convention for the occluded back-pass: world-space dashes so
+# density stays coherent across zoom. Dash + gap = period; dash_width controls
+# the "on" portion.
+_DASH_PERIOD_METERS: float = 0.20
+_DASH_WIDTH_METERS: float = 0.10
+# Solid front pass is rendered wider than the dashed back pass so its halo
+# overpowers the dashed center on visible edges even when the WIRE-display
+# overlay biases the depth buffer at outline pixels.
+_DASH_LINE_WIDTH: float = 1.5
+_SOLID_LINE_WIDTH: float = 2.5
+# Per-iteration default line width used by every non-occlusion draw call in
+# this decorator's ``__call__``. Restored after each occlusion pair so the
+# next draw isn't silently inheriting the wider solid-pass override.
+_DEFAULT_LINE_WIDTH: float = 2.0
+
 
 def _get_cached_batch_or_none(cache_key: tuple[int, str]) -> "gpu.types.GPUBatch | None":
     uid = cache_key[0]
@@ -223,6 +240,15 @@ def _store_batch_in_cache(cache_key: tuple[int, str], batch: "gpu.types.GPUBatch
     _batch_cache[cache_key] = (epoch, batch)
 
 
+def is_filling_supported(element) -> bool:
+    """True when Bonsai's opening generator can derive an opening from this
+    element. IFC's schema permits any IfcElement as a filling; Bonsai
+    currently supports only IfcDoor and IfcWindow because those are the
+    classes with OverallWidth/OverallHeight attributes (or their types'
+    ELEVATION_VIEW profiles) that the generator can consume."""
+    return element is not None and element.is_a() in ("IfcDoor", "IfcWindow")
+
+
 class FilledOpeningGenerator:
     def generate(
         self,
@@ -392,18 +418,16 @@ class FilledOpeningGenerator:
                 representation = tool.Geometry.get_representation_by_context(voided_element, context)
                 assert representation
 
-                bonsai.core.geometry.switch_representation(
-                    tool.Ifc,
-                    tool.Geometry,
-                    obj=voided_obj,
-                    representation=representation,
-                )
+                tool.Geometry.recut_host(voided_obj, representation)
 
     def regenerate_from_type(self, usecase_path: str, ifc_file: ifcopenshell.file, settings: dict[str, Any]) -> None:
         relating_type = settings["relating_type"]
 
-        for related_object in settings["related_objects"]:
-            self._regenerate_from_type(related_object)
+        # Filling type-switch on an array of fillings fans out N host recuts —
+        # one per related object — without batching. Coalesce them.
+        with tool.Geometry.batch_host_recut():
+            for related_object in settings["related_objects"]:
+                self._regenerate_from_type(related_object)
 
     def _regenerate_from_type(self, related_object: ifcopenshell.entity_instance) -> None:
         filling = related_object
@@ -452,12 +476,7 @@ class FilledOpeningGenerator:
             representation = tool.Geometry.get_active_representation(voided_obj)
             if not representation:
                 continue
-            bonsai.core.geometry.switch_representation(
-                tool.Ifc,
-                tool.Geometry,
-                obj=voided_obj,
-                representation=representation,
-            )
+            tool.Geometry.recut_host(voided_obj, representation)
 
     def generate_opening_from_filling(
         self,
@@ -592,6 +611,31 @@ class RecalculateFill(bpy.types.Operator, tool.Ifc.Operator):
         return context.selected_objects
 
     def _execute(self, context):
+        # N selected fillings × M voided host parts would fire N×M host recuts
+        # without batching. Coalesce per host.
+        with tool.Geometry.batch_host_recut():
+            return self._recalculate_fills(context)
+
+    def _recalculate_fills(self, context):
+        # Refresh each selected filling's mapped opening source before
+        # recutting the host. Dedup by source id covers the common shared-
+        # source case in one rewrite while leaving unrelated sibling sources
+        # untouched.
+        seen_source_ids: set[int] = set()
+        for obj in context.selected_objects:
+            element = tool.Ifc.get_entity(obj)
+            if not element or not element.FillsVoids:
+                continue
+            opening = element.FillsVoids[0].RelatingOpeningElement
+            body = tool.Geometry.get_body_representation(opening)
+            if body is None:
+                continue
+            source = tool.Geometry.resolve_mapped_representation(body)
+            if source.id() in seen_source_ids:
+                continue
+            seen_source_ids.add(source.id())
+            tool.Model.regenerate_filling_opening_body(element)
+
         for obj in context.selected_objects:
             element = tool.Ifc.get_entity(obj)
             if not element or not element.FillsVoids:
@@ -620,12 +664,7 @@ class RecalculateFill(bpy.types.Operator, tool.Ifc.Operator):
                 if building_obj and building_obj.data:
                     representation = tool.Geometry.get_active_representation(building_obj)
                     if representation:
-                        bonsai.core.geometry.switch_representation(
-                            tool.Ifc,
-                            tool.Geometry,
-                            obj=building_obj,
-                            representation=representation,
-                        )
+                        tool.Geometry.recut_host(building_obj, representation)
 
         # Refresh cut decorator
         DecoratorData.cut_cache.clear()
@@ -947,27 +986,29 @@ class EditOpenings(Operator, tool.Ifc.Operator):
         for opening_element in opening_elements:
             opening_obj = tool.Ifc.get_object(opening_element)
 
-            similar_openings = bonsai.core.geometry.get_similar_openings(tool.Ifc, opening_element)
-            similar_openings_building_objs = bonsai.core.geometry.get_similar_openings_building_objs(
-                tool.Ifc, similar_openings
-            )
-            building_objs.update(similar_openings_building_objs)
-
             if opening_obj:
-                if tool.Ifc.is_edited(opening_obj):
-                    tool.Geometry.run_geometry_update_representation(obj=opening_obj)
-                    bonsai.core.geometry.edit_similar_opening_placement(
-                        tool.Geometry, opening_element, similar_openings
-                    )
-                elif tool.Ifc.is_moved(opening_obj):
-                    bonsai.core.geometry.edit_object_placement(tool.Ifc, tool.Geometry, tool.Surveyor, obj=opening_obj)
+                opening_edited = tool.Ifc.is_edited(opening_obj)
+                opening_moved = tool.Ifc.is_moved(opening_obj)
+                # Sibling walls only need a viewport-level refresh when the
+                # opening's shape or placement actually changed — a pure
+                # show/hide toggle leaves them in their existing state.
+                if opening_edited or opening_moved:
+                    similar_openings = bonsai.core.geometry.get_similar_openings(tool.Ifc, opening_element)
+                    similar_openings_building_objs = bonsai.core.geometry.get_similar_openings_building_objs(
+                        tool.Ifc, similar_openings
+                    )
+                    building_objs.update(similar_openings_building_objs)
+                    if opening_edited:
+                        tool.Geometry.run_geometry_update_representation(obj=opening_obj)
+                    else:
+                        bonsai.core.geometry.edit_object_placement(
+                            tool.Ifc, tool.Geometry, tool.Surveyor, obj=opening_obj
+                        )
                     bonsai.core.geometry.edit_similar_opening_placement(
                         tool.Geometry, opening_element, similar_openings
                     )
+                    building_objs.update(self.get_all_building_objects_of_similar_openings(opening_element))
 
-                building_objs.update(
-                    self.get_all_building_objects_of_similar_openings(opening_element)
-                )  # NB this has nothing to do with clone similar_opening
                 tool.Ifc.unlink(element=opening_element)
                 if props.representation_obj == opening_obj:
                     props.representation_obj = None
@@ -1005,6 +1046,12 @@ class CloneOpening(Operator, tool.Ifc.Operator):
         return True
 
     def _execute(self, context):
+        # The voided host may be an aggregate whose parts each get recut.
+        # Coalesce per host so a many-parts aggregate doesn't fan out.
+        with tool.Geometry.batch_host_recut():
+            return self._clone_opening(context)
+
+    def _clone_opening(self, context):
         # NOTE: Operator displayed in UI only with IfcOpeningElement being active.
         ifc_file = tool.Ifc.get()
         objects = bpy.context.selected_objects
@@ -1034,12 +1081,7 @@ class CloneOpening(Operator, tool.Ifc.Operator):
                 continue
             representation = tool.Geometry.get_active_representation(obj)
             assert representation
-            bonsai.core.geometry.switch_representation(
-                tool.Ifc,
-                tool.Geometry,
-                obj=obj,
-                representation=representation,
-            )
+            tool.Geometry.recut_host(obj, representation)
 
         return {"FINISHED"}
 
@@ -1189,22 +1231,55 @@ class DecorationsHandler:
         shader.uniform_float("color", color)
         batch.draw(shader)
 
-    def _draw_lines_with_occlusion(self, verts, color, edges_indices, occluded_alpha: float = 0.25, cache_key=None):
-        # One batch, two draws: front pass at full color, occluded pass at
-        # `occluded_alpha`. Save/restore depth_test matches the pattern in
-        # bim/module/structural/decorator.py so callers' state survives.
-        batch = self._get_or_build_batch(self.line_shader, "LINES", verts, edges_indices, cache_key=cache_key)
-        if batch is None:
+    def _draw_lines_with_occlusion(self, verts, color, edges_indices, cache_key=None):
+        # Two-pass CAD hidden-line convention. Both passes use POLYLINE_UNIFORM_COLOR.
+        #
+        # The solid front pass is rendered WIDER than the dashed back pass so it
+        # produces a halo around the line center, beyond the depth-bias zone that
+        # Blender's overlay engine writes when an opening is set to WIRE display.
+        # Without the width difference, the wire bias makes the center-pixel
+        # ``LESS_EQUAL`` comparison fail (line ends up slightly behind the biased
+        # wire depth) so the solid pass would lose to the dashed back pass even
+        # on visible edges. The halo gives the solid pass enough screen-space to
+        # overpower the dashed pattern visually.
+        #
+        # Dashed renders first at the standard width so the solid overlay's wider
+        # halo cleanly hides it on visible edges; on occluded edges the solid
+        # ``LESS_EQUAL`` pass fails against the wall depth and the dashed remains.
+        front_batch = self._get_or_build_batch(self.line_shader, "LINES", verts, edges_indices, cache_key=cache_key)
+        if front_batch is None:
             return
+
+        dashed_cache_key = (cache_key[0], cache_key[1] + "_dashed") if cache_key is not None else None
+        dash_batch = None
+        if dashed_cache_key is not None:
+            dash_batch = _get_cached_batch_or_none(dashed_cache_key)
+        if dash_batch is None:
+            dash_verts, dash_edges = tool.Blender.build_dashed_line_segments(
+                verts, edges_indices, _DASH_PERIOD_METERS, _DASH_WIDTH_METERS
+            )
+            dash_batch = self._get_or_build_batch(self.line_shader, "LINES", dash_verts, dash_edges)
+            if dash_batch is not None and dashed_cache_key is not None:
+                _store_batch_in_cache(dashed_cache_key, dash_batch)
+
         original_depth_test = gpu.state.depth_test_get()
+        front_color = list(color)
+        front_color[3] = 1.0
+        self.line_shader.uniform_float("color", front_color)
+
+        if dash_batch is not None:
+            self.line_shader.uniform_float("lineWidth", _DASH_LINE_WIDTH)
+            gpu.state.depth_test_set("ALWAYS")
+            dash_batch.draw(self.line_shader)
+
+        self.line_shader.uniform_float("lineWidth", _SOLID_LINE_WIDTH)
         gpu.state.depth_test_set("LESS_EQUAL")
-        self.line_shader.uniform_float("color", color)
-        batch.draw(self.line_shader)
-        gpu.state.depth_test_set("GREATER")
-        dimmed = list(color)
-        dimmed[3] = occluded_alpha
-        self.line_shader.uniform_float("color", dimmed)
-        batch.draw(self.line_shader)
+        front_batch.draw(self.line_shader)
+
+        # Restore the per-iteration default set at the top of __call__ so
+        # subsequent draws (the HalfSpaceSolid arrow, future call-sites) are
+        # not silently affected by the front-pass width override.
+        self.line_shader.uniform_float("lineWidth", _DEFAULT_LINE_WIDTH)
         gpu.state.depth_test_set(original_depth_test)
 
     def __call__(self, context):
@@ -1240,7 +1315,7 @@ class DecorationsHandler:
             self.line_shader.bind()  # required to be able to change uniforms of the shader
             # POLYLINE_UNIFORM_COLOR specific uniforms
             self.line_shader.uniform_float("viewportSize", (context.region.width, context.region.height))
-            self.line_shader.uniform_float("lineWidth", 2.0)
+            self.line_shader.uniform_float("lineWidth", _DEFAULT_LINE_WIDTH)
 
             # general shader
             self.shader = gpu.shader.from_builtin("UNIFORM_COLOR")
@@ -1278,9 +1353,7 @@ class DecorationsHandler:
                 self.draw_batch("LINES", verts, selected_elements_color, selected_edges)
                 self.draw_batch("POINTS", unselected_vertices, unselected_elements_color)
                 self.draw_batch("POINTS", selected_vertices, selected_elements_color)
-                obj.data.calc_loop_triangles()
-                tris = [tuple(t.vertices) for t in obj.data.loop_triangles]
-                self.draw_batch("TRIS", verts, transparent_color(special_elements_color), tris)
+                tool.Blender.draw_bmesh_face_tris(bm, verts, transparent_color(special_elements_color), self.draw_batch)
             else:
                 line_verts, verts, edges_indices, tris = _get_cached_world_draw_data(obj)
                 color = selected_elements_color if obj in context.selected_objects else special_elements_color

src/bonsai/bonsai/bim/module/model/preview_base.py

@@ -163,6 +163,59 @@ def sync_uncommitted_moves(objects: list) -> None:
         tool.Geometry.commit_placement_if_moved(obj, apply_scale=False)
 
 
+def clear_preview_state(props: bpy.types.PropertyGroup) -> None:
+    """Reset a preview PropertyGroup to its idle state on commit / cancel.
+
+    Sets ``is_active`` to False and zeros every ``IntProperty`` whose name
+    ends in ``_id`` (the entity-reference convention every preview follows).
+    Other fields are left at their last value — defaults are re-applied on
+    the next enable, so leaving them alone avoids a redundant write."""
+    props.is_active = False
+    for name, rna in props.bl_rna.properties.items():
+        if name.endswith("_id") and rna.type == "INT":
+            setattr(props, name, 0)
+
+
+# --- Standard Finish flow ----------------------------------------------------
+
+
+def commit_preview(
+    operator: bpy.types.Operator,
+    context: bpy.types.Context,
+    attr: str,
+    target_op_name: str,
+    kwarg_names: tuple[str, ...],
+) -> set[str]:
+    """Standard Finish-Preview dispatch: validate context + active preview,
+    read kwargs off the draft, call ``bpy.ops.bim.<target_op_name>(**kwargs)``,
+    and clear the preview on success.
+
+    The dispatched operator's own ``self.report({"ERROR"})`` paths are promoted
+    by ``bpy.ops`` to ``RuntimeError`` — catching it here surfaces the message
+    to the user via ``operator.report`` rather than leaving Blender's operator
+    state half-broken (which silently disables downstream gizmo polls).
+
+    Returns the dispatched operator's result set verbatim so callers can
+    pass it straight back from their own ``execute``."""
+    if context.screen is None:
+        return {"CANCELLED"}
+    props = get_preview_props(context, attr)
+    if props is None or not props.is_active:
+        return {"CANCELLED"}
+    if tool.Ifc.get() is None:
+        operator.report({"ERROR"}, "No IFC file loaded.")
+        return {"CANCELLED"}
+    kwargs = {name: getattr(props, name) for name in kwarg_names}
+    try:
+        result = getattr(bpy.ops.bim, target_op_name)(**kwargs)
+    except RuntimeError as exc:
+        operator.report({"ERROR"}, str(exc))
+        return {"CANCELLED"}
+    if "FINISHED" in result:
+        clear_preview_state(props)
+    return result
+
+
 # --- Esc dispatch ------------------------------------------------------------
 
 PREVIEW_CANCEL_OPS: tuple[tuple[str, str], ...] = (

src/bonsai/bonsai/bim/module/model/profile.py

@@ -1002,6 +1002,14 @@ class EnableEditingExtrusionAxis(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context):
         self.unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
         obj = context.active_object
+
+        # Commit any in-progress parametric (gizmo) draft on this object
+        # before switching to axis-edit. Otherwise the in-memory draft
+        # state is overwritten when the axis mesh is imported below,
+        # silently discarding the user's pending dimension edits.
+        if feature := tool.Parametric.is_object_editing(obj):
+            tool.Parametric.commit_object_draft(obj, feature.finish_op)
+
         element = tool.Ifc.get_entity(obj)
 
         axis = ifcopenshell.util.representation.get_representation(element, "Model", "Axis", "GRAPH_VIEW")
@@ -1157,7 +1165,8 @@ class DrawPolylineProfile(bpy.types.Operator, PolylineOperator, tool.Ifc.Operato
                         DumbProfileJoiner().join_V(profile2["obj"], profile1["obj"])
                         if connect_IfcFlowSegments:
                             bpy.ops.bim.mep_connect_elements(
-                                obj1_name=profile1["obj"].name, obj2_name=profile2["obj"].name
+                                obj1_guid=tool.Ifc.get_entity(profile1["obj"]).GlobalId,
+                                obj2_guid=tool.Ifc.get_entity(profile2["obj"]).GlobalId,
                             )
 
     def modal(self, context, event):

src/bonsai/bonsai/bim/module/model/prop.py

@@ -33,8 +33,10 @@ from bonsai.bim.module.drawing.decoration import CutDecorator
 from bonsai.bim.module.model.data import AuthoringData
 from bonsai.bim.module.model.decorator import (
     BoundingBoxDecorator,
+    MEPSystemPathDecorator,
     SlabDirectionDecorator,
     WallAxisDecorator,
+    WallSystemPathDecorator,
 )
 from bonsai.bim.module.model.door import update_door_modifier_bmesh
 from bonsai.bim.module.model.window import update_window_modifier_bmesh
@@ -132,6 +134,19 @@ def update_slab_direction_decorator(self: "BIMModelProperties", context: bpy.typ
         SlabDirectionDecorator.uninstall()
 
 
+def update_paths_decorator(self: "BIMModelProperties", context: bpy.types.Context) -> None:
+    """Unified toggle for connected-element path overlays. Drives both the
+    MEP and wall path decorators — each decorator's ``draw`` short-circuits
+    when its kind of element isn't selected, so leaving both installed is
+    cheap and lets one toggle cover any connected-element family."""
+    if self.show_paths:
+        MEPSystemPathDecorator.install(bpy.context)
+        WallSystemPathDecorator.install(bpy.context)
+    else:
+        MEPSystemPathDecorator.uninstall()
+        WallSystemPathDecorator.uninstall()
+
+
 def update_measure_xyz(self: "BIMModelProperties", context: bpy.types.Context) -> None:
     if self.show_bounding_box:
         BoundingBoxDecorator.install(context)
@@ -228,11 +243,7 @@ def update_wall_offset_baseline(self: "BIMWallProperties", context: bpy.types.Co
 def update_railing(self: "BIMRailingProperties", context: bpy.types.Context) -> None:
     """Regenerate railing mesh when property changes."""
     if self.is_editing:
-        # Only FRAMELESS_PANEL can update live via bmesh.
-        # WALL_MOUNTED_HANDRAIL geometry is generated from IFC representation,
-        # so it only updates on "Finish Editing" to avoid modifying IFC during preview.
-        if self.railing_type == "FRAMELESS_PANEL":
-            _get_updater("railing", "update_railing_modifier_bmesh")(context)
+        _get_updater("railing", "update_railing_modifier_bmesh")(context)
 
 
 def update_roof(self: "BIMRoofProperties", context: bpy.types.Context) -> None:
@@ -242,6 +253,20 @@ def update_roof(self: "BIMRoofProperties", context: bpy.types.Context) -> None:
         _get_updater("roof", "update_roof_modifier_bmesh")(obj)
 
 
+def update_pipe_segment(self: "BIMPipeSegmentProperties", context: bpy.types.Context) -> None:
+    """Regenerate pipe-segment preview mesh from props during edit. Does NOT touch IFC."""
+    obj = context.active_object
+    if obj and self.is_editing:
+        _get_updater("mep", "regenerate_pipe_segment_mesh_from_props")(obj)
+
+
+def update_duct_segment(self: "BIMDuctSegmentProperties", context: bpy.types.Context) -> None:
+    """Regenerate duct-segment preview mesh from props during edit. Does NOT touch IFC."""
+    obj = context.active_object
+    if obj and self.is_editing:
+        _get_updater("mep", "regenerate_duct_segment_mesh_from_props")(obj)
+
+
 class BIMModelProperties(PropertyGroup):
     ifc_class: bpy.props.EnumProperty(items=get_ifc_class, name="Construction Class", update=update_ifc_class)
     relating_type_id: bpy.props.EnumProperty(
@@ -344,6 +369,19 @@ class BIMModelProperties(PropertyGroup):
         default=False,
         update=update_slab_direction_decorator,
     )
+    show_paths: bpy.props.BoolProperty(
+        name="Show Paths",
+        default=False,
+        update=update_paths_decorator,
+        description=(
+            "Trace the connected element path from the selected element. For "
+            "walls, follows IfcRelConnectsPathElements and draws each "
+            "connected wall's reference axis with endpoint dots. For MEP "
+            "elements, follows IfcRelConnectsPorts and draws each segment's "
+            "axis plus a port-to-port spider for each fitting. Toggle off to "
+            "skip the BFS traversal entirely."
+        ),
+    )
 
     prev_transform_orientation_slot_type: bpy.props.StringProperty(name="Previous Gizmo Orientation Type")
     prev_show_gizmo_object_translate: bpy.props.BoolProperty(name="Previous Gizmo Translate")
@@ -391,6 +429,7 @@ class BIMModelProperties(PropertyGroup):
         offset: float
         show_wall_axis: bool
         show_slab_direction: bool
+        show_paths: bool
 
         prev_transform_orientation_slot_type: str
         prev_show_gizmo_object_translate: bool
@@ -1679,6 +1718,21 @@ class BIMRoofProperties(PropertyGroup):
             setattr(target_props, prop_name, prop_value)
 
 
+class BIMSlabProperties(PropertyGroup):
+    """Transient state for the slab disconnect-access gizmo.
+
+    ``is_editing`` flips True when the user clicks the pen icon on a slab
+    that has wall connections — gating the per-wall disconnect icons in
+    ``GizmoSlabUnjoinWalls`` so they're hidden until the user opts in. No
+    IFC draft state lives here: the disconnect operator commits directly,
+    so this PropertyGroup carries only the UI gate."""
+
+    is_editing: bpy.props.BoolProperty(name="Slab Edit Active", default=False, options={"SKIP_SAVE"})
+
+    if TYPE_CHECKING:
+        is_editing: bool
+
+
 class BIMWallProperties(PropertyGroup):
     """Transient draft state for parametric wall gizmo editing.
 
@@ -1924,6 +1978,155 @@ class BIMExternalParametricGeometryProperties(bpy.types.PropertyGroup):
         sverchok_nodes: Union[sverchok.node_tree.SverchCustomTree, None]
 
 
+class BIMPipeSegmentProperties(PropertyGroup):
+    """Transient draft state for parametric pipe-segment gizmo editing."""
+
+    is_editing: bpy.props.BoolProperty(
+        default=False,
+        description="True while pipe-segment parametric edit mode is active.",
+    )
+    mesh_dirty: bpy.props.BoolProperty(
+        default=False,
+        options={"HIDDEN", "SKIP_SAVE"},
+        description=(
+            "True while the visible mesh is the preview shape; cleared once the "
+            "real IFC-derived geometry is restored (on commit or cancel)."
+        ),
+    )
+    length: bpy.props.FloatProperty(
+        name="Length",
+        default=1.0,
+        min=0.01,
+        subtype="DISTANCE",
+        update=update_pipe_segment,
+        description="Pipe-segment extrusion length (preview value; committed on finish).",
+    )
+    snap_length: bpy.props.FloatProperty(
+        description="Snapshot of length at edit-enable; commit skips no-op writes.",
+    )
+    snap_object_scale_z: bpy.props.FloatProperty(
+        default=1.0,
+        description=(
+            "Snapshot of obj.scale.z at edit-enable. Cancel / no-op-finish restore "
+            "this exact value so a user's non-identity pre-edit scale isn't silently "
+            "zeroed by the scale-based preview."
+        ),
+    )
+
+    if TYPE_CHECKING:
+        is_editing: bool
+        mesh_dirty: bool
+        length: float
+        snap_length: float
+        snap_object_scale_z: float
+
+
+class BIMDuctSegmentProperties(PropertyGroup):
+    """Transient draft state for parametric duct-segment gizmo editing."""
+
+    is_editing: bpy.props.BoolProperty(
+        default=False,
+        description="True while duct-segment parametric edit mode is active.",
+    )
+    mesh_dirty: bpy.props.BoolProperty(
+        default=False,
+        options={"HIDDEN", "SKIP_SAVE"},
+        description=(
+            "True while the visible mesh is the preview shape; cleared once the "
+            "real IFC-derived geometry is restored (on commit or cancel)."
+        ),
+    )
+    length: bpy.props.FloatProperty(
+        name="Length",
+        default=1.0,
+        min=0.01,
+        subtype="DISTANCE",
+        update=update_duct_segment,
+        description="Duct-segment extrusion length (preview value; committed on finish).",
+    )
+    snap_length: bpy.props.FloatProperty(
+        description="Snapshot of length at edit-enable; commit skips no-op writes.",
+    )
+    snap_object_scale_z: bpy.props.FloatProperty(
+        default=1.0,
+        description=(
+            "Snapshot of obj.scale.z at edit-enable. Cancel / no-op-finish restore "
+            "this exact value so a user's non-identity pre-edit scale isn't silently "
+            "zeroed by the scale-based preview."
+        ),
+    )
+
+    if TYPE_CHECKING:
+        is_editing: bool
+        mesh_dirty: bool
+        length: float
+        snap_length: float
+        snap_object_scale_z: float
+
+
+class BIMBendPreviewProperties(PropertyGroup):
+    """Scene-level pending state for the bend-creation preview flow.
+
+    Scene-level (not per-object) because the bend involves two segments by
+    IFC id — neither alone owns the draft."""
+
+    is_active: bpy.props.BoolProperty(
+        default=False,
+        options={"SKIP_SAVE"},
+        description="True while the bend-creation preview flow is active.",
+    )
+    start_segment_id: bpy.props.IntProperty(
+        default=0,
+        options={"SKIP_SAVE"},
+        description="IFC element id of the start (active) segment.",
+    )
+    end_segment_id: bpy.props.IntProperty(
+        default=0,
+        options={"SKIP_SAVE"},
+        description="IFC element id of the end (other selected) segment.",
+    )
+    start_length: bpy.props.FloatProperty(
+        name="Start Length",
+        default=0.1,
+        min=0.001,
+        subtype="DISTANCE",
+        description="Length of the bend fitting's tangent leg on the start (active) segment side",
+    )
+    end_length: bpy.props.FloatProperty(
+        name="End Length",
+        default=0.1,
+        min=0.001,
+        subtype="DISTANCE",
+        description="Length of the bend fitting's tangent leg on the end (other) segment side",
+    )
+    radius: bpy.props.FloatProperty(
+        name="Radius",
+        default=0.2,
+        min=0.001,
+        subtype="DISTANCE",
+        description="Inner radius of the bend curve",
+    )
+    editing_bend_id: bpy.props.IntProperty(
+        default=0,
+        options={"SKIP_SAVE"},
+        description=(
+            "IFC element id of an existing bend fitting being re-edited "
+            "(non-zero only on the pen-icon re-edit flow). The create "
+            "operator deletes this bend + its port connections before "
+            "recreating with the new parameters."
+        ),
+    )
+
+    if TYPE_CHECKING:
+        is_active: bool
+        start_segment_id: int
+        end_segment_id: int
+        start_length: float
+        end_length: float
+        radius: float
+        editing_bend_id: int
+
+
 class BIMWallFilletPreviewProperties(PropertyGroup):
     """Scene-level pending state for the wall-fillet preview flow.
 
@@ -1980,7 +2183,29 @@ class BIMWallFilletPreviewProperties(PropertyGroup):
 class BIMPreviewProperties(PropertyGroup):
     """Umbrella for parametric-edit preview drafts attached to ``Scene``."""
 
+    bend: bpy.props.PointerProperty(type=BIMBendPreviewProperties)
     wall_fillet: bpy.props.PointerProperty(type=BIMWallFilletPreviewProperties)
 
     if TYPE_CHECKING:
+        bend: BIMBendPreviewProperties
         wall_fillet: BIMWallFilletPreviewProperties
+
+
+class BIMParametricEditDialogPrefs(PropertyGroup):
+    """Session-scoped flag for the parametric-edit pen-icon dispatcher.
+
+    Attached to ``WindowManager`` so the state lives for one Blender session
+    and resets on restart — the right scope for "don't show this again for
+    this session" toggles."""
+
+    suppress_shared_rep_warning: bpy.props.BoolProperty(
+        name="Suppress shared-representation warning",
+        description=(
+            "When true, the pen-icon dispatcher skips the shared-geometry "
+            "confirmation dialog. Resets on Blender restart."
+        ),
+        default=False,
+    )
+
+    if TYPE_CHECKING:
+        suppress_shared_rep_warning: bool

src/bonsai/bonsai/bim/module/model/railing.py

@@ -18,6 +18,7 @@
 
 
 import json
+import math
 from typing import Any
 
 import bmesh
@@ -27,14 +28,24 @@ import ifcopenshell.api.geometry
 import ifcopenshell.api.pset
 import ifcopenshell.util.representation
 import ifcopenshell.util.unit
-from mathutils import Vector
+from mathutils import Matrix, Vector
 
 import bonsai.core.geometry
 import bonsai.core.root
 import bonsai.tool as tool
+from bonsai.bim.module.drawing import gizmos as gizmo
+from bonsai.bim.module.drawing.gizmos import DimensionGizmoConfig
+from bonsai.bim.module.model import prop
 from bonsai.bim.module.model.data import RailingData, refresh
 from bonsai.bim.module.model.decorator import ProfileDecorator
-from bonsai.bim.parametric_lifecycle import PathPreservingEditMixin
+from bonsai.bim.parametric_lifecycle import (
+    CycleTypeMixin,
+    PathPreservingEditMixin,
+    PickTypeMixin,
+)
+from bonsai.tool.cad import WELD_TOLERANCE
+
+V_ = tool.Blender.V_
 
 # reference:
 # https://ifc43-docs.standards.buildingsmart.org/IFC/RELEASE/IFC4x3/HTML/lexical/IfcRailing.htm
@@ -125,6 +136,56 @@ def update_bbim_railing_pset(element: ifcopenshell.entity_instance, railing_data
     ifcopenshell.api.pset.edit_pset(tool.Ifc.get(), pset=pset, properties={"Data": railing_data})
 
 
+def generate_wall_mounted_handrail_preview(
+    obj: bpy.types.Object,
+    props: "prop.BIMRailingProperties",
+    path_data: dict[str, Any],
+    si_conversion: float,
+) -> None:
+    """Viewport-only WALL_MOUNTED_HANDRAIL preview: rebuild ``obj.data`` from the same
+    geometry helper the IFC representation builder uses, without writing any IFC."""
+    railing_path = [Vector(v) * si_conversion for v in path_data["verts"]]
+    looped_path = path_data["edges"][-1][-1] == path_data["edges"][0][0]
+
+    geom = ifcopenshell.api.geometry.compute_wall_mounted_handrail_geometry(
+        railing_path=railing_path,
+        support_spacing=props.support_spacing,
+        railing_diameter=props.railing_diameter,
+        clear_width=props.clear_width,
+        height=props.height,
+        use_manual_supports=props.use_manual_supports,
+        terminal_type=props.terminal_type,
+        looped_path=looped_path,
+        unit_scale=1.0,  # props are already SI; bypass the IFC project-units conversion
+    )
+
+    bm = tool.Blender.get_bmesh_for_mesh(obj.data, clean=True)
+
+    tool.Cad.sweep_disk_along_polyline(
+        bm,
+        [Vector(p) for p in geom.handrail_polyline],
+        geom.handrail_radius,
+        arc_indices=geom.handrail_arc_point_indices,
+    )
+
+    for support in geom.supports:
+        tool.Cad.sweep_disk_along_polyline(
+            bm,
+            [Vector(p) for p in support.arc_polyline],
+            support.arc_radius,
+        )
+        tool.Cad.add_disk_extrusion(
+            bm,
+            Vector(support.disk_position),
+            support.disk_radius,
+            support.disk_depth,
+            support.disk_z_rotation,
+        )
+
+    bmesh.ops.recalc_face_normals(bm, faces=bm.faces[:])
+    tool.Blender.apply_bmesh(obj.data, bm)
+
+
 def update_railing_modifier_bmesh(context: bpy.types.Context) -> None:
     """before using should make sure that Data contains up-to-date information.
     If BBIM Pset just changed should call refresh() before updating bmesh
@@ -140,6 +201,13 @@ def update_railing_modifier_bmesh(context: bpy.types.Context) -> None:
     path_data = RailingData.data["path_data"]
 
     si_conversion = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
+
+    # WALL_MOUNTED_HANDRAIL renders the preview from the compute helper; IFC stays
+    # untouched until Finish Editing rebuilds the representation.
+    if not props.is_editing_path and props.railing_type == "WALL_MOUNTED_HANDRAIL":
+        generate_wall_mounted_handrail_preview(obj, props, path_data, si_conversion)
+        return
+
     # need to make sure we support edit mode
     # since users will probably be in edit mode when they'll be changing railing path
     bm = tool.Blender.get_bmesh_for_mesh(obj.data, clean=True)
@@ -165,8 +233,6 @@ def update_railing_modifier_bmesh(context: bpy.types.Context) -> None:
         thickness = props.thickness
         spacing = props.spacing
 
-        # spacing
-        # split each edge in 3 segments by 0.5 * spacing by x-y plane
         main_edges = bm.edges[:]
         for main_edge in main_edges:
             bm_split_edge_at_offset(main_edge, spacing)
@@ -211,7 +277,7 @@ def update_railing_modifier_bmesh(context: bpy.types.Context) -> None:
         bmesh.ops.dissolve_edges(bm, edges=edges_to_dissolve)
         bmesh.ops.dissolve_verts(bm, verts=verts_to_dissolve)
         # to remove unnecessary verts in 0 spacing case
-        bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=0.0001)
+        bmesh.ops.remove_doubles(bm, verts=bm.verts, dist=WELD_TOLERANCE)
 
         bmesh.ops.recalc_face_normals(bm, faces=bm.faces[:])
 
@@ -271,8 +337,8 @@ def get_path_data(obj: bpy.types.Object) -> dict[str, Any]:
             segments.append((i - 1, 0))
             break
 
-        # skip path verts if they just go vertical to avoid errors
-        if (v.co.xy - prev_v.co.xy).length <= 0.0001:
+        # Vertical-only segments project to a degenerate XY edge; skip to avoid divide-by-zero downstream.
+        if (v.co.xy - prev_v.co.xy).length <= WELD_TOLERANCE:
             continue
 
         points.append(v.co)
@@ -407,9 +473,8 @@ class CopyRailingParameters(bpy.types.Operator, tool.Ifc.Operator):
 
 
 class _RailingEditMixin(PathPreservingEditMixin):
-    """Type-specific hooks for railing parametric-edit operators. Single-object
-    (active_object). ``path_data`` is preserved through the edit; the separate
-    ``Enable/Finish/CancelEditingRailingPath`` operators handle path editing."""
+    """Single-object (active_object) railing-edit hooks; path_data is preserved
+    through the edit (path editing is a separate operator family)."""
 
     pset_name = "BBIM_Railing"
 
@@ -436,7 +501,21 @@ class _RailingEditMixin(PathPreservingEditMixin):
         update_railing_modifier_ifc_data(context)
 
     @classmethod
-    def _update_modifier_bmesh(cls, obj: bpy.types.Object, context: bpy.types.Context) -> None:
+    def _restore_viewport_after_cancel(cls, obj: bpy.types.Object, context: bpy.types.Context) -> None:
+        """WALL_MOUNTED_HANDRAIL reloads the committed Body; others rebuild the preview bmesh."""
+        props = tool.Model.get_railing_props(obj)
+        if props.railing_type == "WALL_MOUNTED_HANDRAIL":
+            element = tool.Ifc.get_entity(obj)
+            assert element
+            body = ifcopenshell.util.representation.get_representation(element, "Model", "Body", "MODEL_VIEW")
+            if body:
+                bonsai.core.geometry.switch_representation(
+                    tool.Ifc,
+                    tool.Geometry,
+                    obj=obj,
+                    representation=body,
+                )
+            return
         update_railing_modifier_bmesh(context)
 
 
@@ -467,6 +546,556 @@ class FinishEditingRailing(_RailingEditMixin, bpy.types.Operator, tool.Ifc.Opera
         return self._finish_targets(context)
 
 
+class CycleRailingType(bpy.types.Operator, tool.Ifc.Operator, CycleTypeMixin):
+    """Cycle railing_type (FRAMELESS_PANEL ↔ WALL_MOUNTED_HANDRAIL). Shift+click reverses."""
+
+    bl_idname = "bim.cycle_railing_type"
+    bl_label = "Cycle Railing Type"
+    bl_options = {"REGISTER", "UNDO"}
+
+    element_checker = tool.Parametric.is_railing
+    props_getter = tool.Model.get_railing_props
+    type_literal = tool.Model.RailingType
+    type_attr = "railing_type"
+
+    def _execute(self, context: bpy.types.Context) -> set[str]:
+        return self._cycle_type(context)
+
+
+class ToggleRailingUseManualSupports(bpy.types.Operator):
+    """Flip use_manual_supports on the active WALL_MOUNTED_HANDRAIL railing.
+
+    No-op unless a parametric edit is active and the railing is wall-mounted.
+    """
+
+    bl_idname = "bim.toggle_railing_use_manual_supports"
+    bl_label = "Toggle Railing Manual Supports"
+    bl_description = "Switch between automatic support spacing and manual per-vertex placement"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        resolved = tool.Model.resolve_active_props_for_edit(
+            context,
+            tool.Model.get_railing_props,
+            subtype=("railing_type", "WALL_MOUNTED_HANDRAIL"),
+        )
+        if resolved is None:
+            return {"CANCELLED"}
+        _obj, props = resolved
+        props.use_manual_supports = not props.use_manual_supports
+        return {"FINISHED"}
+
+
+class PickRailingTerminalType(bpy.types.Operator, tool.Ifc.Operator, PickTypeMixin):
+    """Pick ``terminal_type`` for the active WALL_MOUNTED_HANDRAIL railing."""
+
+    bl_idname = "bim.pick_railing_terminal_type"
+    bl_label = "Pick Railing Terminal Type"
+    bl_description = "Pick the cap geometry applied at the rail ends"
+    bl_options = {"REGISTER", "UNDO"}
+
+    skip_element_check = True
+    props_getter = tool.Model.get_railing_props
+    type_literal = prop.CapType
+    type_attr = "terminal_type"
+
+    def _execute(self, context: bpy.types.Context) -> set[str]:
+        if (
+            tool.Model.resolve_active_props_for_edit(
+                context,
+                tool.Model.get_railing_props,
+                subtype=("railing_type", "WALL_MOUNTED_HANDRAIL"),
+            )
+            is None
+        ):
+            return {"CANCELLED"}
+        return self._pick_type(context)
+
+
+def _format_attr_distance(attr_name: str):
+    """text_formatter that renders the named property as a distance, ignoring the
+    dimension's visible-length argument (which is fixed for schematic gizmos)."""
+    return lambda p, _v: tool.Unit.format_distance(getattr(p, attr_name))
+
+
+class GizmoRailingSchematic(bpy.types.GizmoGroup, gizmo.BaseSchematicGizmoGroup):
+    """Schematic-frame parametric editor for railings. Mutually exclusive with path-edit mode."""
+
+    bl_idname = "OBJECT_GGT_bim_railing_edition"
+    bl_label = "Railing Editing Gizmo"
+    bl_space_type = "VIEW_3D"
+    bl_region_type = "WINDOW"
+    bl_options = {"3D", "PERSISTENT"}
+
+    enable_editing_operator = "bim.enable_editing_railing"
+    finish_editing_operator = "bim.finish_editing_railing"
+    cancel_editing_operator = "bim.cancel_editing_railing"
+    cycle_type_operator = "bim.cycle_railing_type"
+
+    props_getter = tool.Model.get_railing_props
+    gizmo_pref_name = "railing"
+
+    # Schematic-local layout. +X → screen RIGHT, +Y → screen UP, +Z → toward viewer
+    # (post billboard rotation). Each dimension is anchored alongside the feature it
+    # measures so the label, not the bar length, carries the value.
+    SCHEMATIC_MESH_HEIGHT_FRAC = 0.9  # Mesh top edge in schematic-local +Y
+    SCHEMATIC_MESH_WIDTH_FRAC = 0.7  # Mesh side edges in schematic-local ±X
+    SCHEMATIC_MESH_RAIL_Y_FRAC = SCHEMATIC_MESH_HEIGHT_FRAC / 2  # WALL_MOUNTED_HANDRAIL rail centreline
+    SCHEMATIC_MESH_DEPTH_FRAC = 0.06  # Panel depth — small so the schematic reads as slabs not boxes
+    # WALL_MOUNTED_HANDRAIL dimensions — fractions of schematic_box_size so they
+    # scale with the host group's box size.
+    SCHEMATIC_RAIL_RADIUS_FRAC = 0.05
+    SCHEMATIC_RAIL_CLEAR_FRAC = 0.5  # Stylised — wider than real-world for visible bracket arm
+    SCHEMATIC_RAIL_INSET_FRAC = 0.08  # Wall extends past the outermost support on both sides
+
+    @classmethod
+    def schematic_rail_radius(cls) -> float:
+        return cls.schematic_box_size * cls.SCHEMATIC_RAIL_RADIUS_FRAC
+
+    @classmethod
+    def schematic_rail_clear(cls) -> float:
+        return cls.schematic_box_size * cls.SCHEMATIC_RAIL_CLEAR_FRAC
+
+    # Axonometric 3/4 view: +Z projects down-and-left so the depth axis
+    # is visibly separated from the back face. Without the X tilt, panel
+    # thickness (schematic-local Z) collapses to a near-horizontal bar.
+    schematic_view_rotation = Matrix.Rotation(math.radians(20), 4, "X") @ Matrix.Rotation(math.radians(-25), 4, "Y")
+
+    # Hover a dimension → highlight the schematic edges tagged with the matching feature.
+    # Tags are written by the mesh builders. "spacing" is empty space (no edges) so it's
+    # absent from this map and gracefully no-ops on hover.
+    schematic_attr_to_feature = {
+        "height": "panel_height",
+        "thickness": "panel_thickness",
+        "railing_diameter": "rail_tube",
+        "clear_width": "bracket",
+        "support_spacing": "bracket",
+    }
+
+    schematic_dimension_props = [
+        # ── FRAMELESS_PANEL ─────────────────────────────────────────────
+        DimensionGizmoConfig(
+            attr_name="height",
+            axis=(0, 1, 0),
+            min_value=0.01,
+            # Gated to FRAMELESS_PANEL: in WALL_MOUNTED_HANDRAIL, height only
+            # feeds TO_FLOOR / TO_END_POST_AND_FLOOR terminals so dragging it
+            # is a no-op under the default "180" terminal.
+            visibility_condition=lambda p: p.railing_type == "FRAMELESS_PANEL",
+            matrix_position=lambda p: Vector((-GizmoRailingSchematic.SCHEMATIC_MESH_WIDTH_FRAC / 2 - 0.08, 0.0, 0.0)),
+            schematic_visible_length=SCHEMATIC_MESH_HEIGHT_FRAC,
+            text_formatter=_format_attr_distance("height"),
+        ),
+        DimensionGizmoConfig(
+            attr_name="thickness",
+            axis=(0, 0, 1),  # panel depth — projects to a true depth direction under the 3/4 tilt
+            min_value=0.005,
+            visibility_condition=lambda p: p.railing_type == "FRAMELESS_PANEL",
+            matrix_position=lambda p: Vector(
+                (
+                    (
+                        -GizmoRailingSchematic.SCHEMATIC_MESH_WIDTH_FRAC / 2
+                        - GizmoRailingSchematic.SCHEMATIC_MESH_GAP_HALF_WIDTH
+                    )
+                    / 2,
+                    GizmoRailingSchematic.SCHEMATIC_MESH_HEIGHT_FRAC + 0.05,
+                    -GizmoRailingSchematic.SCHEMATIC_MESH_DEPTH_FRAC / 2,
+                )
+            ),
+            schematic_visible_length=0.4,  # longer than default to survive depth foreshortening
+            text_formatter=_format_attr_distance("thickness"),
+        ),
+        DimensionGizmoConfig(
+            attr_name="spacing",
+            axis=(1, 0, 0),
+            min_value=0.0,  # zero-spacing collapses the picket gap into a single continuous panel
+            visibility_condition=lambda p: p.railing_type == "FRAMELESS_PANEL",
+            matrix_position=lambda p: Vector((0.0, -0.1, 0.0)),
+            text_formatter=_format_attr_distance("spacing"),
+        ),
+        # ── WALL_MOUNTED_HANDRAIL ──────────────────────────────────────
+        DimensionGizmoConfig(
+            attr_name="railing_diameter",
+            axis=(0, 1, 0),
+            min_value=0.001,
+            visibility_condition=lambda p: p.railing_type == "WALL_MOUNTED_HANDRAIL",
+            matrix_position=lambda p: Vector(
+                (
+                    -GizmoRailingSchematic.SCHEMATIC_MESH_WIDTH_FRAC / 2 - 0.05,
+                    GizmoRailingSchematic.SCHEMATIC_MESH_RAIL_Y_FRAC - 0.09,
+                    GizmoRailingSchematic.schematic_rail_clear(),
+                )
+            ),
+            text_formatter=_format_attr_distance("railing_diameter"),
+        ),
+        DimensionGizmoConfig(
+            attr_name="clear_width",
+            axis=(0, 0, 1),  # +Z is the wall-to-rail perpendicular axis under the 3/4 tilt
+            min_value=0.001,
+            visibility_condition=lambda p: p.railing_type == "WALL_MOUNTED_HANDRAIL",
+            matrix_position=lambda p: Vector(
+                (
+                    0.0,
+                    GizmoRailingSchematic.SCHEMATIC_MESH_RAIL_Y_FRAC,
+                    0.0,
+                )
+            ),
+            schematic_visible_length=0.36,  # 2× default so the call-out survives depth projection
+            text_formatter=_format_attr_distance("clear_width"),
+        ),
+        DimensionGizmoConfig(
+            attr_name="support_spacing",
+            axis=(1, 0, 0),
+            min_value=0.05,
+            visibility_condition=lambda p: (p.railing_type == "WALL_MOUNTED_HANDRAIL" and not p.use_manual_supports),
+            matrix_position=lambda p: Vector(
+                (
+                    -GizmoRailingSchematic.SCHEMATIC_MESH_WIDTH_FRAC / 2
+                    + GizmoRailingSchematic.SCHEMATIC_RAIL_INSET_FRAC,
+                    -0.18,
+                    0.0,
+                )
+            ),
+            # Bare names (not Gizmo…SCHEMATIC_…) because the class is still under construction here.
+            schematic_visible_length=SCHEMATIC_MESH_WIDTH_FRAC - 2 * SCHEMATIC_RAIL_INSET_FRAC,
+            text_formatter=_format_attr_distance("support_spacing"),
+        ),
+    ]
+
+    @classmethod
+    def is_element_type(cls, element: ifcopenshell.entity_instance) -> bool:
+        return tool.Parametric.is_railing(element)
+
+    @classmethod
+    def schematic_cache_key(cls, props) -> tuple:
+        """Cache the schematic mesh by ``railing_type`` — proportions are fixed
+        per type, so the bmesh build runs at most twice across a session
+        (once for ``FRAMELESS_PANEL``, once for ``WALL_MOUNTED_HANDRAIL``)
+        rather than once per draw call."""
+        return (props.railing_type,)
+
+    def setup_element_specific_gizmos(self, context: bpy.types.Context) -> None:
+        """Create the WALL_MOUNTED_HANDRAIL-only affordances on the schematic.
+
+        Two static lock glyphs (open/closed) for toggling
+        ``use_manual_supports``: instantiate both and let the per-frame state
+        query pick which one to show. State-aware icons use a static pair
+        rather than a single dynamic gizmo to avoid ``prop_path`` resolution
+        in the render path.
+
+        Plus a cycle-glyph at the rail end that opens the ``terminal_type``
+        popup when clicked.
+        """
+        default_color, highlight_color = self.get_decoration_colors()
+
+        self.lock_open_gizmo, self.lock_closed_gizmo = self.create_icon_gizmo_lock_pair(
+            "bim.toggle_railing_use_manual_supports",
+            open_color=default_color,
+        )
+
+        self.terminal_gizmo = self.gizmos.new("VIEW3D_GT_menu")
+        self.terminal_gizmo.color = default_color
+        self.terminal_gizmo.color_highlight = highlight_color
+        self.terminal_gizmo.use_draw_scale = False
+        self.terminal_gizmo.alpha = 0.8
+        self.terminal_gizmo.target_set_operator("bim.pick_railing_terminal_type")
+
+    def _refresh_element_specific(self, context: bpy.types.Context, mw: "Matrix", props) -> None:
+        """Position and gate the WALL_MOUNTED_HANDRAIL-only gizmos.
+
+        - Lock glyphs: only WALL_MOUNTED_HANDRAIL while editing. Show
+          ``lock_open`` when ``use_manual_supports`` is True, the closed
+          padlock when False ("auto-spacing is locked to support_spacing").
+        - Terminal gizmo: same gating, positioned just past the right rail
+          end so it reads as "configure the rail's end cap".
+        """
+        super()._refresh_element_specific(context, mw, props)
+
+        # ``draw_prepare`` can fire on a freshly recreated GizmoGroup instance
+        # before ``setup_element_specific_gizmos`` has populated the lock /
+        # terminal attributes (Blender 5.x recreates per-region groups on
+        # reload). Bail out cheaply; the next refresh after setup completes
+        # will reposition them correctly.
+        if not hasattr(self, "lock_open_gizmo"):
+            return
+
+        # Single gate for all WALL_MOUNTED_HANDRAIL extras.
+        active = props.is_editing and not props.is_editing_path and props.railing_type == "WALL_MOUNTED_HANDRAIL"
+
+        if not active:
+            self.lock_open_gizmo.hide = True
+            self.lock_closed_gizmo.hide = True
+            self.terminal_gizmo.hide = True
+            return
+
+        billboard_rot = self._frame_billboard_rot
+        view_rotation = self.schematic_view_rotation
+        anchor = self._compute_schematic_anchor(props, mw, billboard_rot)
+
+        # ── Lock glyphs for use_manual_supports ──────────────────────────
+        # Sit just above the wall's bottom line, near the centre of the
+        # schematic — visually grouped with the dimension it controls
+        # (support_spacing) without overlapping the arrow tail below.
+        is_manual = bool(props.use_manual_supports)
+        self.lock_open_gizmo.hide = not is_manual
+        self.lock_closed_gizmo.hide = is_manual
+        lock_local = Vector((0.0, 0.05, 0.0))
+        lock_world = anchor + billboard_rot @ view_rotation @ lock_local
+        lock_matrix = gizmo.billboarded_at(lock_world, billboard_rot, 0.09)
+        self.lock_open_gizmo.matrix_basis = lock_matrix
+        self.lock_closed_gizmo.matrix_basis = lock_matrix
+
+        # ── Terminal-type popup gizmo at the right rail end ──────────────
+        # Pushed well past the right wall edge so the icon doesn't crowd
+        # the wall outline or the bracket attach point. At rail height and
+        # rail depth so it reads as "attached to the rail terminal".
+        self.terminal_gizmo.hide = False
+        terminal_local = Vector(
+            (
+                self.SCHEMATIC_MESH_WIDTH_FRAC / 2 + 0.25,
+                self.SCHEMATIC_MESH_RAIL_Y_FRAC,
+                self.schematic_rail_clear(),
+            )
+        )
+        terminal_world = anchor + billboard_rot @ view_rotation @ terminal_local
+        self.terminal_gizmo.matrix_basis = gizmo.billboarded_at(terminal_world, billboard_rot, 0.18)
+
+    def update_editing_gizmos(
+        self, context: bpy.types.Context, mw: "Matrix", props: "prop.BIMRailingProperties"
+    ) -> None:
+        """Hide the pen gizmo while polyline path-edit is active; reposition the cycle icon.
+
+        The base class shows the pen gizmo whenever ``is_editing`` is False,
+        which is the case during path-edit too. Allowing the user to click
+        through into parametric edit while the polyline mesh is open in EDIT
+        mode mixes two distinct editing states and leaves a stale draft if
+        they cancel out — block the entry point instead. The operator itself
+        is intentionally not guarded (callers via scripting can still invoke
+        it); this is the UX-level enforcement.
+
+        The cycle icon defaults to the editing icon row (next to validate /
+        cancel) via the parent's positioning. We move it to just above the
+        schematic mesh so it reads as "cycle the railing type *shown here*"
+        — associated with the preview the user is interacting with, not a
+        generic editing button at the bottom of the schematic.
+        """
+        super().update_editing_gizmos(context, mw, props)
+        if props.is_editing_path:
+            self.pen_gizmo.hide = True
+
+        if props.is_editing and not props.is_editing_path:
+            billboard_rot = self._frame_billboard_rot
+            view_rotation = self.schematic_view_rotation
+            anchor = self._compute_schematic_anchor(props, mw, billboard_rot)
+            # Comfortably above the mesh top edge so the icon doesn't crowd
+            # the ``thickness`` / ``clear_width`` dimension callouts that
+            # already sit just above the panel/wall.
+            cycle_local = Vector((0.0, self.SCHEMATIC_MESH_HEIGHT_FRAC + 0.25, 0.0))
+            world_pos = anchor + billboard_rot @ view_rotation @ cycle_local
+            # 30% smaller than the editing-icon-row default (0.30 → 0.21):
+            # the cycle is a tertiary affordance compared to pen/validate/cancel.
+            self.cycle_gizmo.matrix_basis = gizmo.billboarded_at(world_pos, billboard_rot, 0.21)
+
+    @classmethod
+    def build_schematic_mesh(cls, props) -> "bmesh.types.BMesh":
+        """Build a wireframe preview of the railing in schematic-local coordinates.
+
+        FRAMELESS_PANEL renders as a box whose proportions track the bound
+        properties (height / thickness / spacing); WALL_MOUNTED_HANDRAIL
+        renders as a horizontal tube with two L-shaped supports whose
+        proportions track railing_diameter / clear_width / support_spacing.
+        Both are scaled to fit inside ``[-schematic_box_size, +schematic_box_size]``
+        on each axis so the schematic reads the same regardless of absolute
+        property values.
+
+        The mesh is decorative — clicks land on the labeled sliders, not on
+        the preview geometry. See ``BaseSchematicGizmoGroup`` for the
+        draw-handler lifecycle.
+        """
+        bm = bmesh.new()
+        if props.railing_type == "FRAMELESS_PANEL":
+            cls._build_frameless_panel_schematic(bm, props)
+        else:
+            cls._build_wall_mounted_handrail_schematic(bm, props)
+        return bm
+
+    # Schematic-local half-width of the visible gap between the two panel boxes.
+    # Conveys the "spacing" semantic at a glance — the user sees two pickets
+    # separated by air, with the spacing dimension emerging from that gap.
+    SCHEMATIC_MESH_GAP_HALF_WIDTH = 0.05
+
+    @classmethod
+    def _build_frameless_panel_schematic(cls, bm: "bmesh.types.BMesh", props) -> None:
+        """Stylised panel: two wireframe boxes with a visible gap between them.
+
+        The box edges sit at the ``SCHEMATIC_MESH_*_FRAC`` positions
+        (matching where the dimension gizmos anchor), so each dimension line
+        visually starts at the geometry feature it measures. Internal
+        proportions are stable across drags — the actual values are shown
+        through the dimension labels, while the schematic communicates
+        which feature each label refers to. The gap between the two boxes
+        (set by ``SCHEMATIC_MESH_GAP_HALF_WIDTH``) gives the "spacing"
+        dimension a real visual referent.
+
+        Edges are tagged on a string layer so hover-highlight can colour
+        the geometric feature being measured: vertical edges → height,
+        depth edges → thickness. The X-aligned edges along the panel
+        width are untagged (they don't correspond to a single dimension).
+        """
+        hw = cls.SCHEMATIC_MESH_WIDTH_FRAC / 2
+        hd = cls.SCHEMATIC_MESH_DEPTH_FRAC / 2
+        h_top = cls.SCHEMATIC_MESH_HEIGHT_FRAC
+        gap = cls.SCHEMATIC_MESH_GAP_HALF_WIDTH
+
+        layer_name = cls.SCHEMATIC_FEATURE_LAYER_NAME
+        feat_layer = bm.edges.layers.string.get(layer_name) or bm.edges.layers.string.new(layer_name)
+
+        # Edge index → feature tag for one box. Order matches the (a, b)
+        # tuple order below: bottom ring (4) + top ring (4) + verticals (4).
+        edge_tags_per_box = (
+            b"",  # (0,1) bottom-back, X-aligned
+            b"panel_thickness",  # (1,2) bottom-right, Z-aligned
+            b"",  # (2,3) bottom-front, X-aligned
+            b"panel_thickness",  # (3,0) bottom-left, Z-aligned
+            b"",  # (4,5) top-back, X-aligned
+            b"panel_thickness",  # (5,6) top-right, Z-aligned
+            b"",  # (6,7) top-front, X-aligned
+            b"panel_thickness",  # (7,4) top-left, Z-aligned
+            b"panel_height",  # (0,4) vertical back-left
+            b"panel_height",  # (1,5) vertical back-right
+            b"panel_height",  # (2,6) vertical front-right
+            b"panel_height",  # (3,7) vertical front-left
+        )
+
+        # Build two separate wireframe boxes — one on each side of the central
+        # gap. The boxes share the same Y range (0..h_top) and Z range (±hd)
+        # but split the X range so the gap from -gap to +gap stays empty.
+        for x_left, x_right in ((-hw, -gap), (gap, hw)):
+            corners = [
+                bm.verts.new((x_left, 0.0, -hd)),
+                bm.verts.new((x_right, 0.0, -hd)),
+                bm.verts.new((x_right, 0.0, hd)),
+                bm.verts.new((x_left, 0.0, hd)),
+                bm.verts.new((x_left, h_top, -hd)),
+                bm.verts.new((x_right, h_top, -hd)),
+                bm.verts.new((x_right, h_top, hd)),
+                bm.verts.new((x_left, h_top, hd)),
+            ]
+            for tag, (a, b) in zip(
+                edge_tags_per_box,
+                (
+                    (0, 1),
+                    (1, 2),
+                    (2, 3),
+                    (3, 0),  # bottom ring
+                    (4, 5),
+                    (5, 6),
+                    (6, 7),
+                    (7, 4),  # top ring
+                    (0, 4),
+                    (1, 5),
+                    (2, 6),
+                    (3, 7),  # vertical edges
+                ),
+            ):
+                edge = bm.edges.new((corners[a], corners[b]))
+                if tag:
+                    edge[feat_layer] = tag
+
+    @classmethod
+    def _build_wall_mounted_handrail_schematic(cls, bm: "bmesh.types.BMesh", props) -> None:
+        """Stylised wall-mounted handrail: wall outline, hex tube, two L-brackets.
+
+        Three visual elements convey "rail mounted on a wall":
+
+        - **Wall outline** — a wireframe rectangle in the YZ plane at ``z=0``,
+          extending slightly past the rail ends so the wall reads as a
+          surface the rail is *attached to* rather than a coincident frame.
+        - **Handrail tube** — a hexagonal cross-section extruded along ±X
+          at ``z=+clear_s`` (in front of the wall), at ``y=rail_y``.
+        - **L-shaped brackets** at each rail end — from the rail centreline
+          drop a short distance, then run perpendicular back to the wall
+          plane. Mirrors the standard wall-mount bracket geometry: a
+          horizontal arm holding the rail off the wall, a vertical drop
+          attaching to the rail.
+
+        Like ``_build_frameless_panel_schematic``, the schematic uses fixed
+        proportions so the dimension gizmos' anchor points stay aligned
+        with the geometry features regardless of property values.
+        """
+        half_len = cls.SCHEMATIC_MESH_WIDTH_FRAC / 2
+        wall_top = cls.SCHEMATIC_MESH_HEIGHT_FRAC
+        rail_y = cls.SCHEMATIC_MESH_RAIL_Y_FRAC  # rail sits at half wall height
+        radius_s = cls.schematic_rail_radius()
+        clear_s = cls.schematic_rail_clear()
+
+        layer_name = cls.SCHEMATIC_FEATURE_LAYER_NAME
+        feat_layer = bm.edges.layers.string.get(layer_name) or bm.edges.layers.string.new(layer_name)
+
+        # ── Wall outline (rectangle at z=0, slightly wider than the rail) ──
+        # Spans the full schematic height; the rail attaches in the middle,
+        # so the wall reads as "continuing past the rail above and below".
+        # Wall edges stay untagged — they're background context, not a
+        # feature any dimension measures.
+        wall_extra = 0.08
+        wall_x_left = -half_len - wall_extra
+        wall_x_right = half_len + wall_extra
+        wall_corners = [
+            bm.verts.new((wall_x_left, 0.0, 0.0)),
+            bm.verts.new((wall_x_right, 0.0, 0.0)),
+            bm.verts.new((wall_x_right, wall_top, 0.0)),
+            bm.verts.new((wall_x_left, wall_top, 0.0)),
+        ]
+        for a, b in ((0, 1), (1, 2), (2, 3), (3, 0)):
+            bm.edges.new((wall_corners[a], wall_corners[b]))
+
+        # ── Handrail tube (hex cross-section in YZ, extruded along X) ──────
+        # Centred on the rail centreline at (±(half_len - rail_inset),
+        # rail_y, +clear_s) — in front of the wall plane at z=0. The tube
+        # is shorter than the wall so the wall visibly extends past it on
+        # both sides; the L-brackets sit at the tube ends, so the leftmost
+        # bracket no longer coincides with the wall's left edge.
+        rail_inset = cls.SCHEMATIC_RAIL_INSET_FRAC
+        rail_x_left = -half_len + rail_inset
+        rail_x_right = half_len - rail_inset
+        segments = 6
+        ring_left, ring_right = [], []
+        for i in range(segments):
+            theta = 2 * math.pi * i / segments
+            dy = math.cos(theta) * radius_s
+            dz = math.sin(theta) * radius_s
+            ring_left.append(bm.verts.new((rail_x_left, rail_y + dy, clear_s + dz)))
+            ring_right.append(bm.verts.new((rail_x_right, rail_y + dy, clear_s + dz)))
+        # All hex-tube edges tagged "rail_tube" so they highlight together
+        # when the railing_diameter dimension is hovered.
+        for i in range(segments):
+            j = (i + 1) % segments
+            e_left = bm.edges.new((ring_left[i], ring_left[j]))
+            e_right = bm.edges.new((ring_right[i], ring_right[j]))
+            e_axial = bm.edges.new((ring_left[i], ring_right[i]))
+            e_left[feat_layer] = b"rail_tube"
+            e_right[feat_layer] = b"rail_tube"
+            e_axial[feat_layer] = b"rail_tube"
+
+        # ── L-brackets at each rail end (rail → drop → wall) ───────────────
+        # Bracket attach points follow the rail ends, so they're pulled
+        # inward by ``rail_inset`` from the wall edges. From the rail
+        # centreline, drop ``bracket_drop`` in Y, then run perpendicular
+        # back to the wall plane (z=0). The L shape reads as a wall-mount
+        # bracket under the 3/4 tilt. Both bracket segments tagged
+        # "bracket" so they highlight when clear_width OR support_spacing
+        # is hovered (both dimensions measure features of the supports).
+        bracket_drop = 0.06
+        for x in (rail_x_left, rail_x_right):
+            v_rail = bm.verts.new((x, rail_y, clear_s))
+            v_corner = bm.verts.new((x, rail_y - bracket_drop, clear_s))
+            v_wall = bm.verts.new((x, rail_y - bracket_drop, 0.0))
+            e1 = bm.edges.new((v_rail, v_corner))
+            e2 = bm.edges.new((v_corner, v_wall))
+            e1[feat_layer] = b"bracket"
+            e2[feat_layer] = b"bracket"
+
+
 class FlipRailingPathOrder(bpy.types.Operator, tool.Ifc.Operator):
     bl_idname = "bim.flip_railing_path_order"
     bl_label = "Flip Railing Path Order"
@@ -510,6 +1139,16 @@ class EnableEditingRailingPath(bpy.types.Operator, tool.Ifc.Operator):
         [o.select_set(False) for o in context.selected_objects if o != obj]
         assert obj
         props = tool.Model.get_railing_props(obj)
+
+        # Auto-commit any in-progress parametric draft before switching to
+        # path-edit. ``set_props_kwargs_from_ifc_data`` a few lines below
+        # overwrites props with the pset's stored values — without committing
+        # first, anything the user dragged on a dimension gizmo (height,
+        # diameter, …) would be silently discarded the moment path-edit
+        # starts.
+        if props.is_editing:
+            tool.Parametric.commit_object_draft(obj, "bim.finish_editing_railing")
+
         data = tool.Model.get_modeling_bbim_pset_data(obj, "BBIM_Railing")["data_dict"]
         # required since we could load pset from .ifc and BIMRoofProperties won't be set
         props.set_props_kwargs_from_ifc_data(data)

src/bonsai/bonsai/bim/module/model/slab.py

@@ -271,7 +271,7 @@ class DumbSlabPlaner:
                 # For instances, a 30 degrees angled extrusion with positive direction has the same extrusion direction as a
                 # -150 degrees angled extrusion with negative direction. The difference lies in the object's rotation.
                 # This means that things can get messy if the user changes the object x angle somehow. We have to figure out an alternative approach.
-                existing_x_angle = obj.rotation_euler.x
+                existing_x_angle = tool.Model.get_existing_x_angle(extrusion)
                 existing_x_angle = 0 if tool.Cad.is_x(existing_x_angle, 0, tolerance=0.001) else existing_x_angle
                 existing_x_angle = 0 if tool.Cad.is_x(existing_x_angle, pi, tolerance=0.001) else existing_x_angle
                 existing_x_angle = 0 if tool.Cad.is_x(existing_x_angle, 2 * pi, tolerance=0.001) else existing_x_angle
@@ -620,6 +620,14 @@ class EnableEditingExtrusionProfile(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context):
         self.unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
         obj = context.active_object
+
+        # Commit any in-progress parametric (gizmo) draft on this object
+        # before switching to profile-edit. Otherwise the in-memory draft
+        # state is overwritten when the profile mesh is imported below,
+        # silently discarding the user's pending dimension edits.
+        if feature := tool.Parametric.is_object_editing(obj):
+            tool.Parametric.commit_object_draft(obj, feature.finish_op)
+
         element = tool.Ifc.get_entity(obj)
 
         body = ifcopenshell.util.representation.get_representation(element, "Model", "Body", "MODEL_VIEW")
@@ -991,3 +999,74 @@ class RecalculateSlab(bpy.types.Operator, tool.Ifc.Operator):
 
         tool.Model.recalculate_walls(walls)
         return {"FINISHED"}
+
+
+class EnableEditingSlab(bpy.types.Operator, tool.Ifc.Operator):
+    """Open the slab disconnect-access mode. Pure UI toggle: flips
+    ``obj.BIMSlabProperties.is_editing`` so the per-wall disconnect
+    gizmos surface on the slab. ``tool.Ifc.Operator`` base because the
+    parametric framework's universal dispatcher routes through
+    ``tool.Parametric.run_bim_op``, which only accepts that subclass for
+    undo-safe lifecycle. No IFC mutation."""
+
+    bl_idname = "bim.enable_editing_slab"
+    bl_label = "Edit Slab Connections"
+    bl_description = "Show disconnect icons for every wall clipped to this slab"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        obj = context.active_object
+        if obj is None:
+            return False
+        element = tool.Ifc.get_entity(obj)
+        return element is not None and element.is_a("IfcSlab")
+
+    def _execute(self, context):
+        context.active_object.BIMSlabProperties.is_editing = True
+        return {"FINISHED"}
+
+
+class CancelEditingSlab(bpy.types.Operator, tool.Ifc.Operator):
+    """Close the slab disconnect-access mode."""
+
+    bl_idname = "bim.cancel_editing_slab"
+    bl_label = "Close Slab Edit"
+    bl_description = "Hide the slab disconnect icons"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        obj = context.active_object
+        if obj is None:
+            return False
+        element = tool.Ifc.get_entity(obj)
+        return element is not None and element.is_a("IfcSlab")
+
+    def _execute(self, context):
+        context.active_object.BIMSlabProperties.is_editing = False
+        return {"FINISHED"}
+
+
+class FinishEditingSlab(bpy.types.Operator, tool.Ifc.Operator):
+    """Close the slab disconnect-access mode. Same body as Cancel — slab
+    edit is a pure UI gate with no IFC draft to commit; the framework
+    requires both ``bim.finish_editing_<name>`` and
+    ``bim.cancel_editing_<name>`` to exist by name convention."""
+
+    bl_idname = "bim.finish_editing_slab"
+    bl_label = "Finish Slab Edit"
+    bl_description = "Hide the slab disconnect icons"
+    bl_options = {"REGISTER", "UNDO"}
+
+    @classmethod
+    def poll(cls, context):
+        obj = context.active_object
+        if obj is None:
+            return False
+        element = tool.Ifc.get_entity(obj)
+        return element is not None and element.is_a("IfcSlab")
+
+    def _execute(self, context):
+        context.active_object.BIMSlabProperties.is_editing = False
+        return {"FINISHED"}

src/bonsai/bonsai/bim/module/model/ui.py

@@ -22,9 +22,9 @@ from collections.abc import Iterable
 from typing import TYPE_CHECKING, Any
 
 import bpy
+import ifcopenshell.util.unit
 from bpy.types import Panel
 
-import ifcopenshell.util.unit
 import bonsai.bim
 import bonsai.tool as tool
 from bonsai.bim.helper import prop_with_search

src/bonsai/bonsai/bim/module/model/workspace.py

@@ -963,7 +963,11 @@ class EditObjectUI:
 
     @classmethod
     def draw_regen_operations(cls, row, ui_context):
-        if AuthoringData.data["is_regenable_element"]:
+        # ``AuthoringData.load`` flips ``is_loaded`` at entry as a recursion
+        # guard, so a partial load (any computation along the way raising)
+        # leaves the tail keys unset. ``.get()`` keeps the header draw alive
+        # until the underlying failure is investigated.
+        if AuthoringData.data.get("is_regenable_element"):
             row = cls.layout.row(align=True) if ui_context != "TOOL_HEADER" else row
             add_layout_hotkey_operator(row, "Regen", "S_G", "Recalculate Element Geometry", ui_context)
 
@@ -1317,7 +1321,7 @@ class Hotkey(bpy.types.Operator, tool.Ifc.Operator):
                 bpy.ops.bim.recalculate_profile()
         elif self.active_class in ("IfcWindow", "IfcWindowStandardCase", "IfcDoor", "IfcDoorStandardCase"):
             bpy.ops.bim.recalculate_fill()
-        elif self.active_class in ("IfcSpace"):
+        elif self.active_class in ("IfcSpace",):
             bpy.ops.bim.generate_space()
 
     def hotkey_S_M(self):

src/bonsai/bonsai/bim/module/nest/decorator.py

@@ -20,7 +20,6 @@ import blf
 import bpy
 import gpu
 import ifcopenshell.util.element
-from bpy.types import SpaceView3D
 from bpy_extras import view3d_utils
 from gpu_extras.batch import batch_for_shader
 from mathutils import Vector
@@ -28,12 +27,6 @@ from mathutils import Vector
 import bonsai.tool as tool
 
 
-def transparent_color(color, alpha=0.1):
-    color = [i for i in color]
-    color[3] = alpha
-    return color
-
-
 def create_bounding_box(objs):
     # Initialize the bounding box coordinates
     min_x, min_y, min_z = float("inf"), float("inf"), float("inf")
@@ -79,26 +72,8 @@ def create_bounding_box(objs):
     return indices, edges
 
 
-class NestDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_nest, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
+class NestDecorator(tool.Blender.ViewportDecorator):
+    draw_method = "draw_nest"
 
     def dotted_line_shader(self):
         vert_out = gpu.types.GPUStageInterfaceInfo("my_interface")
@@ -154,14 +129,6 @@ class NestDecorator:
         shader.uniform_float("u_Scale", 25)
         batch.draw(shader)
 
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
-
     def draw_nest(self, context: bpy.types.Context) -> None:
         props = tool.Nest.get_nest_props()
         if props.in_nest_mode:
@@ -226,35 +193,11 @@ class NestDecorator:
             self.draw_custom_batch(line, decorator_color_unselected)
 
 
-class NestModeDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_nest_name, (context,), "WINDOW", "POST_PIXEL"))
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_nest_empty, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
+class NestModeDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_nest_name", "POST_PIXEL"),
+        ("draw_nest_empty", "POST_VIEW"),
+    )
 
     def draw_nest_name(self, context):
         if context.mode == "EDIT_MESH":

src/bonsai/bonsai/bim/module/patch/__init__.py

@@ -21,6 +21,7 @@ import bpy
 from . import operator, prop, ui
 
 classes = (
+    operator.AddIfcPatchPreset,
     operator.ExecuteIfcPatch,
     operator.ExtractSelectedElements,
     operator.RunMigratePatch,
@@ -28,6 +29,7 @@ classes = (
     operator.SelectIfcPatchOutput,
     operator.UpdateIfcPatchArguments,
     prop.BIMPatchProperties,
+    ui.BIM_MT_ifc_patch_presets,
     ui.BIM_PT_patch,
 )
 

src/bonsai/bonsai/bim/module/patch/operator.py

@@ -18,11 +18,12 @@
 
 import json
 from pathlib import Path
-from typing import TYPE_CHECKING, cast
+from typing import TYPE_CHECKING
 
 import bpy
 import ifcopenshell
 import ifcpatch
+from bl_operators.presets import AddPresetBase
 from bpy_extras.io_utils import ExportHelper, ImportHelper
 
 import bonsai.bim.handler
@@ -77,6 +78,27 @@ class ExecuteIfcPatch(bpy.types.Operator):
             return False
         return True
 
+    def invoke(self, context, event):
+        # Migrating IFC4 → IFC2X3 is lossy (enum drops, IFC4-only classes
+        # become IfcBuildingElementProxy, tessellated meshes get rebuilt as
+        # IfcFacetedBrep). Confirm before running so the user knows.
+        if tool.Patch.migration_is_lossy_downgrade():
+            return context.window_manager.invoke_props_dialog(self, width=480)
+        return self.execute(context)
+
+    def draw(self, context):
+        layout = self.layout
+        layout.label(text="Downgrading to IFC2X3 is lossy.", icon="ERROR")
+        column = layout.column(align=True)
+        column.label(text="Geometry will be preserved as faithfully as possible:")
+        column.label(text="• IfcIndexedPolyCurve → IfcPolyline (arcs approximated by chords)")
+        column.label(text="• IfcPolygonalFaceSet / IfcTriangulatedFaceSet → IfcFacetedBrep")
+        column.separator()
+        column.label(text="The following information is lost:")
+        column.label(text="• IFC4-only classes (IfcLamp, IfcPipeSegment, …) → IfcBuildingElementProxy")
+        column.label(text="• PredefinedType enum values absent from IFC2X3 are dropped")
+        column.label(text="  (original class + enum saved as ObjectType, e.g. 'IfcLamp/COMPACTFLUORESCENT')")
+
     def execute(self, context):
         props = tool.Patch.get_patch_props()
         recipe_name = props.ifc_patch_recipes
@@ -100,8 +122,8 @@ class ExecuteIfcPatch(bpy.types.Operator):
         if props.should_load_from_memory and tool.Ifc.get():
             args["file"] = tool.Ifc.get()
         else:
-            args["input"] = cast(str, props.ifc_patch_input)
-            args["file"] = cast(ifcopenshell.file, ifcopenshell.open(props.ifc_patch_input))
+            args["input"] = props.ifc_patch_input
+            args["file"] = ifcopenshell.open(props.ifc_patch_input)
 
         # Store this in case the patch recipe resets the Blender session, such as by loading a new project.
         ifc_patch_output = props.ifc_patch_output or props.ifc_patch_input
@@ -224,3 +246,38 @@ class ExtractSelectedElements(bpy.types.Operator):
         query = tool.Search.get_query_for_selected_elements()
         props.ifc_patch_args_attr[0].string_value = query
         return {"FINISHED"}
+
+
+class AddIfcPatchPreset(AddPresetBase, bpy.types.Operator):
+    """Save / remove ifc-patch argument presets, scoped per recipe.
+
+    Presets live in the standard Blender preset directory under
+    ``bonsai/ifc_patch/<recipe>/`` so a preset created for ``ExtractElements``
+    does not pollute the preset list for ``Migrate``. Persistence across files
+    and sessions is inherited from Blender's preset system."""
+
+    bl_idname = "bim.add_ifc_patch_preset"
+    bl_label = "Add IFC Patch Preset"
+    preset_menu = "BIM_MT_ifc_patch_presets"
+    preset_defines = ["props = bpy.context.scene.BIMPatchProperties"]
+
+    @property
+    def preset_subdir(self) -> str:
+        return tool.Patch.get_preset_subdir()
+
+    @property
+    def preset_values(self) -> list[str]:
+        # `Attribute.get_value_name()` returns the storage field for the
+        # argument's data_type (string_value, bool_value, …). For file
+        # arguments it returns the wrapping PointerProperty (`filepath_value`)
+        # — the scalar path the preset needs is `.single_file` on that.
+        props = tool.Patch.get_patch_props()
+        values = []
+        for i, arg in enumerate(props.ifc_patch_args_attr):
+            field = arg.get_value_name()
+            if not field:
+                continue
+            if arg.data_type == "file":
+                field = f"{field}.single_file"
+            values.append(f"props.ifc_patch_args_attr[{i}].{field}")
+        return values

src/bonsai/bonsai/bim/module/patch/prop.py

@@ -71,6 +71,15 @@ def get_ifcpatch_recipes(self: "BIMPatchProperties", context: bpy.types.Context)
 
 def update_ifc_patch_recipe(self: "BIMPatchProperties", context: bpy.types.Context) -> None:
     bpy.ops.bim.update_ifc_patch_arguments(recipe=self.ifc_patch_recipes)
+    # Blender's script.execute_preset mutates the menu class's bl_label to
+    # the loaded preset's display name (used as a "currently selected"
+    # indicator). The label persists across recipe changes — making the new
+    # recipe's menu falsely show the previous recipe's preset name. Reset
+    # the label to the menu's canonical title so it always matches the
+    # active recipe's preset list.
+    menu_cls = getattr(bpy.types, "BIM_MT_ifc_patch_presets", None)
+    if menu_cls is not None:
+        menu_cls.bl_label = "IFC Patch Presets"
 
 
 class BIMPatchProperties(PropertyGroup):

src/bonsai/bonsai/bim/module/patch/ui.py

@@ -29,6 +29,20 @@ if TYPE_CHECKING:
     from bonsai.bim.prop import Attribute
 
 
+class BIM_MT_ifc_patch_presets(bpy.types.Menu):
+    """Lists ifc-patch presets for the currently selected recipe.
+
+    ``preset_subdir`` is resolved per draw so switching recipes swaps the
+    preset list without re-registering the menu."""
+
+    bl_label = "IFC Patch Presets"
+    preset_operator = "script.execute_preset"
+
+    def draw(self, context: bpy.types.Context) -> None:
+        self.preset_subdir = tool.Patch.get_preset_subdir()
+        bpy.types.Menu.draw_preset(self, context)
+
+
 class BIM_PT_patch(bpy.types.Panel):
     bl_label = "Patch"
     bl_idname = "BIM_PT_patch"
@@ -66,6 +80,11 @@ class BIM_PT_patch(bpy.types.Panel):
                 row.operator("bim.patch_query_from_selected", text="", icon="EYEDROPPER")
 
         if props.ifc_patch_args_attr:
+            preset_row = layout.row(heading="Preset", align=True)
+            preset_row.menu("BIM_MT_ifc_patch_presets", text=BIM_MT_ifc_patch_presets.bl_label)
+            preset_row.operator("bim.add_ifc_patch_preset", text="", icon="ADD")
+            preset_row.operator("bim.add_ifc_patch_preset", text="", icon="REMOVE").remove_active = True
+
             draw_callback = draw_callback_ if props.ifc_patch_recipes == "ExtractElements" else None
             draw_attributes(props.ifc_patch_args_attr, layout, callback=draw_callback)
 

src/bonsai/bonsai/bim/module/project/__init__.py

@@ -18,6 +18,8 @@
 
 import bpy
 
+import bonsai.tool as tool
+
 from . import decorator, gizmo, operator, prop, ui, workspace
 
 classes = (
@@ -28,6 +30,12 @@ classes = (
     operator.AppendLibraryElementByQuery,
     operator.AssignLibraryDeclaration,
     operator.BIM_FH_import_ifc,
+    operator.BIM_OT_apply_pending_opening_cuts,
+    operator.BIM_OT_dismiss_multi_instance_warning,
+    operator.BIM_OT_dismiss_pending_array_repair,
+    operator.BIM_OT_dismiss_pending_opening_cuts,
+    operator.BIM_OT_select_pending_array_repair,
+    operator.BIM_OT_select_pending_opening_cuts,
     operator.BIM_OT_load_clipping_planes,
     operator.BIM_OT_save_clipping_planes,
     operator.ChangeLibraryElement,
@@ -52,6 +60,8 @@ classes = (
     operator.LinkIfc,
     operator.LoadBlendMetadataAndIFC,
     operator.LoadLink,
+    operator.AutosavePrompt,
+    operator.LoadAutosavedRecoveryPopup,
     operator.LoadLinkedProject,
     operator.LoadProject,
     operator.LoadProjectElements,
@@ -82,6 +92,8 @@ classes = (
     prop.FilterCategory,
     prop.Link,
     prop.EditedObj,
+    prop.PendingArrayRepair,
+    prop.PendingOpeningRecut,
     prop.BIMProjectProperties,
     prop.MeasureToolSettings,
     ui.BIM_MT_new_project,
@@ -128,6 +140,7 @@ def register():
 def unregister():
     if not bpy.app.background:
         bpy.utils.unregister_tool(workspace.ExploreTool)
+    tool.Autosave.cancel_timer()
     del bpy.types.Scene.BIMProjectProperties
     del bpy.types.Scene.MeasureToolSettings
     bpy.app.handlers.load_post.remove(decorator.toggle_decorations_on_load)

src/bonsai/bonsai/bim/module/project/data.py

@@ -162,8 +162,8 @@ class ProjectLibraryData:
         library_file = IfcStore.library_file
         if library_file is None or library_file.schema == "IFC2X3":
             return results
-        project = library_file.by_type("IfcProject")[0]
-        results.append((str(project.id()), f"IfcProject {project.Name or 'Unnamed'}", project.Description or ""))
+        root = tool.Project.get_root_context(library_file)
+        results.append((str(root.id()), f"{root.is_a()} {root.Name or 'Unnamed'}", root.Description or ""))
         for library_id, data in cls.data["project_libraries"].items():
             results.append((str(library_id), data["Name"] or "Unnamed", data["Description"] or ""))
         return results

src/bonsai/bonsai/bim/module/project/decorator.py

@@ -42,12 +42,6 @@ def toggle_decorations_on_load(*args):
     # as queried object is linked from separate .blend file.
 
 
-def transparent_color(color, alpha=0.1):
-    color = [i for i in color]
-    color[3] = alpha
-    return color
-
-
 class ProjectDecorator:
     installed = None
 
@@ -80,11 +74,6 @@ class ProjectDecorator:
         unselected_elements_color = self.addon_prefs.decorator_color_unselected
         special_elements_color = self.addon_prefs.decorator_color_special
 
-        def transparent_color(color, alpha=0.1):
-            color = [i for i in color]
-            color[3] = alpha
-            return color
-
         gpu.state.point_size_set(6)
         gpu.state.blend_set("ALPHA")
 
@@ -110,7 +99,9 @@ class ProjectDecorator:
 
         if geom.selected_edges:
             self.draw_batch("LINES", selected_vertices, selected_elements_color, geom.selected_edges)
-            self.draw_batch("TRIS", selected_vertices, transparent_color(selected_elements_color), geom.selected_tris)
+            self.draw_batch(
+                "TRIS", selected_vertices, tool.Blender.transparent_color(selected_elements_color), geom.selected_tris
+            )
 
 
 class ClippingPlaneDecorator:
@@ -145,11 +136,6 @@ class ClippingPlaneDecorator:
         unselected_elements_color = self.addon_prefs.decorator_color_unselected
         special_elements_color = self.addon_prefs.decorator_color_special
 
-        def transparent_color(color, alpha=0.1):
-            color = [i for i in color]
-            color[3] = alpha
-            return color
-
         gpu.state.point_size_set(6)
         gpu.state.blend_set("ALPHA")
 
@@ -210,37 +196,21 @@ class ClippingPlaneDecorator:
 
             if unselected_edges:
                 self.draw_batch("LINES", unselected_vertices, special_elements_color, unselected_edges)
-                self.draw_batch("TRIS", unselected_vertices, transparent_color(special_elements_color), unselected_tris)
+                self.draw_batch(
+                    "TRIS", unselected_vertices, tool.Blender.transparent_color(special_elements_color), unselected_tris
+                )
             if selected_edges:
                 self.draw_batch("LINES", selected_vertices, selected_elements_color, selected_edges)
-                self.draw_batch("TRIS", selected_vertices, transparent_color(selected_elements_color), selected_tris)
+                self.draw_batch(
+                    "TRIS", selected_vertices, tool.Blender.transparent_color(selected_elements_color), selected_tris
+                )
 
 
-class MeasureDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(
-            SpaceView3D.draw_handler_add(handler.draw_measurements_text, (context,), "WINDOW", "POST_PIXEL")
-        )
-        cls.handlers.append(
-            SpaceView3D.draw_handler_add(handler.draw_measurements_poly, (context,), "WINDOW", "POST_VIEW")
-        )
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
+class MeasureDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_measurements_text", "POST_PIXEL"),
+        ("draw_measurements_poly", "POST_VIEW"),
+    )
 
     def draw_measurements_text(self, context):
         PolylineDecorator().select_and_draw_measurements_text(context)

src/bonsai/bonsai/bim/module/project/operator.py

@@ -281,9 +281,9 @@ class RefreshLibrary(bpy.types.Operator):
         elements = {e for e in elements if not tool.Project.is_element_assigned_to_project_library(e, rels)}
         self.props.add_library_project_library("Unassigned", len(elements), 0, False)
 
-        ifc_project = library_file.by_type("IfcProject")[0]
+        root_context = tool.Project.get_root_context(library_file)
         hierarchy = tool.Project.get_project_hierarchy(library_file)
-        tool.Project.load_project_libraries_to_ui(ifc_project, hierarchy)
+        tool.Project.load_project_libraries_to_ui(root_context, hierarchy)
         return {"FINISHED"}
 
 
@@ -763,7 +763,10 @@ class EditProjectLibrary(bpy.types.Operator):
         previous_parent_library = tool.Project.get_parent_library(project_library)
         new_parent_library = library_file.by_id(int(props.parent_library))
         if previous_parent_library != new_parent_library:
-            if previous_parent_library.is_a("IfcProject"):
+            if previous_parent_library is None:
+                # Edited library was a root in a library-only file; nest it under the new parent.
+                ifcopenshell.api.nest.assign_object(library_file, [project_library], new_parent_library)
+            elif previous_parent_library.is_a("IfcProject"):
                 # Then new one is IfcProjectLibrary.
                 ifcopenshell.api.nest.assign_object(library_file, [project_library], new_parent_library)
             else:  # Previous is IfcProjectLibrary.
@@ -804,9 +807,12 @@ class AddProjectLibrary(bpy.types.Operator):
         props = tool.Project.get_project_props()
         library_file = IfcStore.library_file
         assert library_file
-        project = library_file.by_type("IfcProject")[0]
+        root_context = tool.Project.get_root_context(library_file)
         project_library = ifcopenshell.api.root.create_entity(library_file, "IfcProjectLibrary")
-        ifcopenshell.api.project.assign_declaration(library_file, [project_library], project)
+        if root_context.is_a("IfcProject"):
+            ifcopenshell.api.project.assign_declaration(library_file, [project_library], root_context)
+        else:
+            ifcopenshell.api.nest.assign_object(library_file, [project_library], root_context)
         ProjectLibraryData.load()  # Update enum.
         props.selected_project_library = str(project_library.id())
         props.is_editing_project_library = True
@@ -979,8 +985,10 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
         ),
         default=False,
     )
+    skip_autosave_recovery: bpy.props.BoolProperty(default=False, options={"HIDDEN", "SKIP_SAVE"})
     use_detailed_tooltip: bpy.props.BoolProperty(default=False, options={"HIDDEN"})
     filename_ext = ".ifc"
+    skip_recent: bpy.props.BoolProperty(default=False, options={"HIDDEN", "SKIP_SAVE"})
 
     if TYPE_CHECKING:
         filepath: str
@@ -989,6 +997,7 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
         use_relative_path: bool
         should_start_fresh_session: bool
         import_without_ifc_data: bool
+        skip_autosave_recovery: bool
         use_detailed_tooltip: bool
 
     @classmethod
@@ -1035,7 +1044,33 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
 
         return tooltip
 
+    def check_autosave_recovery(self, context: bpy.types.Context) -> bool:
+        if self.skip_autosave_recovery:
+            return False
+        autosaved_filepath = tool.Autosave.get_newer_autosaved_path(self.get_filepath_abs())
+        if not autosaved_filepath:
+            return False
+        # Fire-and-forget: don't propagate this popup's own RUNNING_MODAL
+        # return value up as if *this* operator were running modally too -
+        # we never call modal_handler_add() on ourselves, so the window
+        # manager would be left tracking a modal operator with no handler,
+        # corrupting its operator bookkeeping until it crashes later when
+        # the (real) popup modal handler is closed.
+        bpy.ops.bim.load_autosaved_recovery_popup(
+            "INVOKE_DEFAULT",
+            original_filepath=str(self.get_filepath_abs()),
+            autosaved_filepath=autosaved_filepath,
+            is_advanced=self.is_advanced,
+            use_relative_path=self.use_relative_path,
+            should_start_fresh_session=self.should_start_fresh_session,
+            import_without_ifc_data=self.import_without_ifc_data,
+        )
+        return True
+
     def execute(self, context):
+        if self.check_autosave_recovery(context):
+            return {"FINISHED"}
+
         if (
             tool.Blender.get_addon_preferences().save_metadata_blend_file
             and self.should_start_fresh_session
@@ -1113,6 +1148,14 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
                     f"Error loading IFC file from filepath '{filepath}'. See logs above in the system console for the details.",
                 )
                 return {"CANCELLED"}
+            if not tool.Ifc.get().by_type("IfcProject"):
+                self.report(
+                    {"ERROR"},
+                    "This file contains no IfcProject. It is likely an IFC project library — "
+                    "load it via Project Setup → Project Library → Select Library File instead.",
+                )
+                IfcStore.purge()
+                return {"CANCELLED"}
             props = tool.Project.get_project_props()
             props.is_loading = True
             props.total_elements = len(tool.Ifc.get().by_type("IfcElement"))
@@ -1122,7 +1165,8 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
             props.should_save_metadata_for_this_file = metadata_doc is not None
 
             tool.Blender.register_toolbar()
-            tool.Project.add_recent_ifc_project(self.get_filepath_abs())
+            if not self.skip_recent:
+                tool.Project.add_recent_ifc_project(self.get_filepath_abs())
 
             if self.is_advanced:
                 pass
@@ -1135,10 +1179,13 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
         except:
             bonsai.last_error = traceback.format_exc()
             raise
+        tool.Autosave.reset_timer()
         return {"FINISHED"}
 
     def invoke(self, context, event):
         if self.filepath:
+            if self.check_autosave_recovery(context):
+                return {"FINISHED"}
             return self.execute(context)
         return ImportHelper.invoke(self, context, event)
 
@@ -1223,6 +1270,30 @@ class LoadProjectElements(bpy.types.Operator):
         props = tool.Project.get_project_props()
         props.is_loading = False
 
+        # Stash elements the kernel skipped opening cuts on (HasOpenings > void_limit).
+        # The Project panel banner offers the user a one-click recut.
+        props.pending_opening_recut.clear()
+        if ifc_importer.gross_elements:
+            for element in ifc_importer.gross_elements:
+                item = props.pending_opening_recut.add()
+                item.ifc_definition_id = element.id()
+            self.report(
+                {"WARNING"},
+                f"{len(ifc_importer.gross_elements)} element(s) had too many openings and were loaded without cuts. "
+                f"Apply manually from the Project panel.",
+            )
+
+        props.pending_array_repair.clear()
+        if ifc_importer.broken_arrays:
+            for element in ifc_importer.broken_arrays:
+                item = props.pending_array_repair.add()
+                item.ifc_definition_id = element.id()
+            self.report(
+                {"WARNING"},
+                f"{len(ifc_importer.broken_arrays)} array parent(s) reference missing child GUIDs. "
+                f"Inspect from the Project panel.",
+            )
+
         tool.Project.load_default_thumbnails()
         tool.Project.set_default_context()
         tool.Project.set_default_modeling_dimensions()
@@ -1256,6 +1327,11 @@ class LoadProjectElements(bpy.types.Operator):
             if element.IsDecomposedBy:
                 for subelement in element.IsDecomposedBy[0].RelatedObjects:
                     decomposed_elements.add(subelement)
+            # IfcSurfaceFeature (e.g. road markings) adhere to a host element
+            # via IfcRelAdheresToElement, a [1:1] hierarchical relationship in
+            # the same family as aggregation, containment and nesting (IFC4.3).
+            for rel in getattr(element, "HasSurfaceFeatures", ()):
+                decomposed_elements.update(rel.RelatedSurfaceFeatures)
         if decomposed_elements:
             self.append_decomposed_elements(decomposed_elements)
         elements.update(decomposed_elements)
@@ -1384,6 +1460,7 @@ class LinkIfc(bpy.types.Operator, ImportHelper, tool.Ifc.Operator):
                 new.ifc_definition_id = reference.id()
             new.name = filepath
             new.filepath = filepath
+            new.query = self.query
             bpy.ops.bim.load_link(link_index=-1, use_cache=self.use_cache, query=self.query)
 
 
@@ -1454,6 +1531,10 @@ class LoadLink(bpy.types.Operator, tool.Ifc.Operator):
 
     def _execute(self, context):
         self.link = tool.Project.get_project_props().links[self.link_index]
+        # Fall back to the Link's stored query so callers that omit it
+        # still replay the filter the link was created with.
+        if not self.query and self.link.query:
+            self.query = self.link.query
         filepath = Path(tool.Ifc.resolve_uri(self.link.filepath))
         if not filepath.exists():
             self.report({"ERROR"}, f"File does not exist: '{filepath}'")
@@ -1621,13 +1702,36 @@ class ReloadLink(bpy.types.Operator):
     bl_description = "Reload the selected file"
 
     link_index: bpy.props.IntProperty(name="Link Index")
+    query: bpy.props.StringProperty(
+        name="Query",
+        description=(
+            "Custom selector query to use to load element from a linked model. E.g. 'IfcElement'.\n\n"
+            "Default query - IfcElement, but excluding IfcProxy, IfcSpatialStructureElement, IfcSpatialElement, IfcFeatureElement."
+        ),
+    )
 
     if TYPE_CHECKING:
         link_index: int
+        query: str
+
+    def invoke(self, context, event):
+        link = tool.Project.get_project_props().links[self.link_index]
+        self.query = link.query
+        return context.window_manager.invoke_props_dialog(self)
+
+    def draw(self, context):
+        assert self.layout
+        self.layout.prop(self, "query", placeholder="IfcElement")
 
     def execute(self, context):
+        link = tool.Project.get_project_props().links[self.link_index]
+        # An unset query means the operator was called without the dialog
+        # (e.g. from a script) - preserve the link's stored query instead
+        # of overwriting it with the empty default.
+        if self.properties.is_property_set("query"):
+            link.query = self.query
         bpy.ops.bim.unload_link(link_index=self.link_index)
-        return bpy.ops.bim.load_link(link_index=self.link_index, use_cache=False) or {"FINISHED"}
+        return bpy.ops.bim.load_link(link_index=self.link_index, use_cache=False, query=link.query) or {"FINISHED"}
 
 
 class ToggleLinkSelectability(bpy.types.Operator):
@@ -1876,6 +1980,7 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
     json_compact: bpy.props.BoolProperty(name="Export Compact IFCJSON", default=False)
     should_save_as: bpy.props.BoolProperty(name="Should Save As", default=False, options={"HIDDEN"})
     use_relative_path: bpy.props.BoolProperty(name="Use Relative Path", default=False)
+    skip_recent: bpy.props.BoolProperty(default=False, options={"HIDDEN", "SKIP_SAVE"})
 
     if TYPE_CHECKING:
         filter_glob: str
@@ -1936,6 +2041,18 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
         return {"FINISHED"}
 
     def _execute(self, context):
+        project_props = tool.Project.get_project_props()
+        project_props.use_relative_project_path = self.use_relative_path
+
+        # Fallback if filepath is not set
+        if not getattr(self, "filepath", None) or self.filepath.strip() in ("", ".ifc"):
+            props = tool.Blender.get_bim_props()
+            if props.ifc_file:
+                self.filepath = str(tool.Blender.ensure_blender_path_is_abs(Path(props.ifc_file)))
+            else:
+                self.report({"ERROR"}, "No filepath available for saving.")
+                return {"CANCELLED"}
+
         committed, failed_commits = tool.Parametric.commit_pending_edits()
         # Previews are session-transient — discard rather than commit. Sibling
         # gizmo polls gate on each preview's is_active flag, and a stuck flag
@@ -1998,7 +2115,8 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
         settings.logger.info("Export finished in {:.2f} seconds".format(time.time() - start))
         print("Export finished in {:.2f} seconds".format(time.time() - start))
         # New project created in Bonsai should be in recent projects too.
-        tool.Project.add_recent_ifc_project(Path(output_file))
+        if not self.skip_recent:
+            tool.Project.add_recent_ifc_project(Path(output_file))
         props = tool.Project.get_project_props()
         if props.use_relative_project_path and bpy.data.is_saved:
             output_file = os.path.relpath(output_file, bpy.path.abspath("//"))
@@ -2032,6 +2150,7 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
             )
 
         bonsai.bim.handler.refresh_ui_data()
+        tool.Autosave.reset_timer()
 
     @classmethod
     def description(cls, context, properties):
@@ -2040,6 +2159,123 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
         return "Save the IFC file.  Will save both .IFC/.BLEND files if synced together"
 
 
+class LoadAutosavedRecoveryPopup(bpy.types.Operator):
+    bl_idname = "bim.load_autosaved_recovery_popup"
+    bl_label = "Recover Autosaved File"
+    bl_options = {"REGISTER", "UNDO"}
+
+    original_filepath: bpy.props.StringProperty(options={"SKIP_SAVE"})
+    autosaved_filepath: bpy.props.StringProperty(options={"SKIP_SAVE"})
+    is_advanced: bpy.props.BoolProperty(default=False, options={"SKIP_SAVE"})
+    use_relative_path: bpy.props.BoolProperty(default=False, options={"SKIP_SAVE"})
+    should_start_fresh_session: bpy.props.BoolProperty(default=True, options={"SKIP_SAVE"})
+    import_without_ifc_data: bpy.props.BoolProperty(default=False, options={"SKIP_SAVE"})
+
+    def draw(self, context):
+        layout = self.layout
+        layout.label(text="A newer autosaved copy was found:", icon="INFO")
+        layout.label(text=os.path.basename(self.autosaved_filepath))
+        layout.separator()
+        layout.label(text="Do you want to load the autosaved version instead?")
+        layout.label(text="(Cancel will load the original)")
+
+    def invoke(self, context, event):
+        # invoke_props_dialog is modal - unlike invoke_popup/popup_menu, it
+        # isn't dismissed by the mouse simply leaving its bounds. It always
+        # renders both a fixed "Cancel" button and this confirm_text one, so
+        # the question is framed as Yes/Cancel rather than adding separate
+        # Load buttons on top.
+        return context.window_manager.invoke_props_dialog(
+            self, width=420, title="Recover Autosaved File", confirm_text="Yes"
+        )
+
+    def _load_kwargs(self, filepath: str, skip_recent: bool) -> dict:
+        return dict(
+            filepath=filepath,
+            skip_autosave_recovery=True,  # Prevent infinite loop
+            is_advanced=self.is_advanced,
+            use_relative_path=self.use_relative_path,
+            should_start_fresh_session=self.should_start_fresh_session,
+            import_without_ifc_data=self.import_without_ifc_data,
+            skip_recent=skip_recent,
+        )
+
+    @staticmethod
+    def _defer(callback) -> None:
+        def on_timer() -> None:
+            callback()
+            return None
+
+        # bim.load_project (with should_start_fresh_session, our default)
+        # calls wm.read_homefile(), which tears down the window
+        # manager/screens/regions. Calling that synchronously from this
+        # dialog's execute()/cancel() - themselves invoked from deep inside
+        # Blender's modal handling for this popup's button click - frees
+        # data that the still-on-stack caller dereferences once we return,
+        # segfaulting Blender. Deferring by one timer tick runs the reload
+        # after the popup's own modal handling has fully unwound. The
+        # callback only closes over plain values (not `self`), since the
+        # operator instance itself may no longer be valid by the time the
+        # timer fires.
+        bpy.app.timers.register(on_timer, first_interval=0.0)
+
+    def execute(self, context):
+        kwargs = self._load_kwargs(self.autosaved_filepath, skip_recent=True)
+        original_filepath = self.original_filepath
+
+        def load_and_repoint() -> None:
+            bpy.ops.bim.load_project(**kwargs)
+            # Re-point tracking at the original path so future saves write
+            # back to it, not "_autosaved.ifc".
+            tool.Ifc.set_path(original_filepath)
+
+        self._defer(load_and_repoint)
+        return {"FINISHED"}
+
+    def cancel(self, context):
+        # Also reached via Escape or a click outside the dialog, not just Cancel.
+        kwargs = self._load_kwargs(self.original_filepath, skip_recent=False)
+        self._defer(lambda: bpy.ops.bim.load_project(**kwargs))
+
+
+class AutosavePrompt(bpy.types.Operator):
+    bl_idname = "bim.autosave_prompt"
+    bl_label = "Autosave Reminder"
+    bl_options = set()
+
+    def invoke(self, context, event):
+        return context.window_manager.invoke_props_dialog(
+            self, width=400, confirm_text="Save", title="Autosave Reminder"
+        )
+
+    def draw(self, context):
+        layout = self.layout
+        layout.label(text="The autosave timer has expired.", icon="INFO")
+        layout.label(text="Would you like to save your IFC project now?")
+
+    def execute(self, context):
+        # Get current IFC path
+        props = tool.Blender.get_bim_props()
+        current_ifc_path = props.ifc_file
+
+        if not current_ifc_path:
+            self.report({"WARNING"}, "No IFC file path set. Please save manually.")
+            tool.Autosave.reset_timer()
+            return {"CANCELLED"}
+
+        # Call save_project with explicit filepath using EXEC_DEFAULT
+        result = bpy.ops.bim.save_project(
+            "EXEC_DEFAULT", filepath=current_ifc_path, should_save_as=False, skip_recent=True
+        )
+
+        tool.Autosave.reset_timer()
+        return result
+
+    def cancel(self, context):
+        tool.Autosave.reset_timer()
+        return {"CANCELLED"}
+
+
 class LoadLinkedProject(bpy.types.Operator, ImportHelper):
     bl_idname = "bim.load_linked_project"
     bl_label = "Load Project For Viewing Only"
@@ -3421,3 +3657,149 @@ class GenerateUVMap(bpy.types.Operator):
         tool.Loader.load_generated_uv_map(obj.data)
         self.report({"INFO"}, "Generated UV map for selected mesh.")
         return {"FINISHED"}
+
+
+class BIM_OT_apply_pending_opening_cuts(bpy.types.Operator, tool.Ifc.Operator):
+    """Recompute the wall mesh including opening subtractions for every host
+    that the load-time ``void_limit`` filter skipped. Clears the deferred
+    list on completion so the panel banner disappears."""
+
+    bl_idname = "bim.apply_pending_opening_cuts"
+    bl_label = "Apply Pending Opening Cuts"
+    bl_description = (
+        "Recompute meshes for elements whose openings were skipped at load because they had too many openings"
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    def _execute(self, context: bpy.types.Context) -> set[str]:
+        pending = tool.Project.get_project_props().pending_opening_recut
+        applied = 0
+        skipped = 0
+        failed = 0
+        for item in pending:
+            try:
+                element = tool.Ifc.get().by_id(item.ifc_definition_id)
+            except RuntimeError:
+                skipped += 1
+                continue
+            obj = tool.Ifc.get_object(element)
+            if obj is None:
+                skipped += 1
+                continue
+            body = ifcopenshell.util.representation.get_representation(element, "Model", "Body", "MODEL_VIEW")
+            if body is None:
+                skipped += 1
+                continue
+            try:
+                tool.Geometry.reimport_element_representations(obj, body, apply_openings=True)
+                applied += 1
+            except (RuntimeError, OSError, AttributeError) as exc:
+                # Programmer errors (TypeError, ValueError, etc.) must surface — don't swallow them.
+                failed += 1
+                print(f"apply_pending_opening_cuts: failed to recompute {element} ({exc})")
+
+        pending.clear()
+        message = f"Applied opening cuts to {applied} element(s)."
+        if skipped:
+            message += f" {skipped} entry/entries skipped (entity or object no longer available)."
+        if failed:
+            message += f" {failed} entry/entries failed (see system console)."
+            self.report({"WARNING"}, message)
+        else:
+            self.report({"INFO"}, message)
+        return {"FINISHED"}
+
+
+class BIM_OT_dismiss_pending_opening_cuts(bpy.types.Operator):
+    bl_idname = "bim.dismiss_pending_opening_cuts"
+    bl_label = "Dismiss Pending Opening Cuts"
+    bl_description = "Clear the pending opening-cut list without applying it. Walls stay solid where openings would have been subtracted."
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        tool.Project.get_project_props().pending_opening_recut.clear()
+        return {"FINISHED"}
+
+
+class BIM_OT_dismiss_multi_instance_warning(bpy.types.Operator):
+    bl_idname = "bim.dismiss_multi_instance_warning"
+    bl_label = "Dismiss Multi-Instance Warning"
+    bl_description = (
+        "Hide the warning that another Blender instance has this IFC file open. Sticky for the current session."
+    )
+    bl_options = {"REGISTER"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        from bonsai.bim.ifc import dismiss_multi_instance_warning
+
+        dismiss_multi_instance_warning()
+        return {"FINISHED"}
+
+
+class BIM_OT_select_pending_opening_cuts(bpy.types.Operator):
+    bl_idname = "bim.select_pending_opening_cuts"
+    bl_label = "Select Elements With Skipped Opening Cuts"
+    bl_description = "Select the Blender objects whose openings were skipped at load. Useful for locating which elements need attention."
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        ifc_file = tool.Ifc.get()
+        if ifc_file is None:
+            self.report({"INFO"}, "No IFC file loaded.")
+            return {"CANCELLED"}
+        objects: list[bpy.types.Object] = []
+        for item in tool.Project.get_project_props().pending_opening_recut:
+            try:
+                element = ifc_file.by_id(item.ifc_definition_id)
+            except RuntimeError:
+                continue
+            obj = tool.Ifc.get_object(element)
+            if obj is not None:
+                objects.append(obj)
+        if not objects:
+            self.report({"INFO"}, "No matching Blender objects found for the pending list.")
+            return {"CANCELLED"}
+        tool.Blender.set_objects_selection(context, active_object=objects[0], selected_objects=objects)
+        self.report({"INFO"}, f"Selected {len(objects)} element(s).")
+        return {"FINISHED"}
+
+
+class BIM_OT_select_pending_array_repair(bpy.types.Operator):
+    bl_idname = "bim.select_pending_array_repair"
+    bl_label = "Select Array Parents With Missing Children"
+    bl_description = "Select the Blender objects of array parents whose BBIM_Array.Data references children that don't resolve in the file."
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        ifc_file = tool.Ifc.get()
+        if ifc_file is None:
+            self.report({"INFO"}, "No IFC file loaded.")
+            return {"CANCELLED"}
+        objects: list[bpy.types.Object] = []
+        for item in tool.Project.get_project_props().pending_array_repair:
+            try:
+                element = ifc_file.by_id(item.ifc_definition_id)
+            except RuntimeError:
+                continue
+            obj = tool.Ifc.get_object(element)
+            if obj is not None:
+                objects.append(obj)
+        if not objects:
+            self.report({"INFO"}, "No matching Blender objects found for the pending list.")
+            return {"CANCELLED"}
+        tool.Blender.set_objects_selection(context, active_object=objects[0], selected_objects=objects)
+        self.report({"INFO"}, f"Selected {len(objects)} array parent(s).")
+        return {"FINISHED"}
+
+
+class BIM_OT_dismiss_pending_array_repair(bpy.types.Operator):
+    bl_idname = "bim.dismiss_pending_array_repair"
+    bl_label = "Dismiss Pending Array Repair"
+    bl_description = (
+        "Clear the pending array-repair list without acting on it. The underlying BBIM_Array.Data stays unchanged."
+    )
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context: bpy.types.Context) -> set[str]:
+        tool.Project.get_project_props().pending_array_repair.clear()
+        return {"FINISHED"}

src/bonsai/bonsai/bim/module/project/prop.py

@@ -98,7 +98,8 @@ def is_editing_project_library_update(self: "BIMProjectProperties", context: bpy
         project_library = library_file.by_id(int(self.selected_project_library))
         self.project_library_attributes.clear()
         bonsai.bim.helper.import_attributes(project_library, self.project_library_attributes)
-        self.parent_library = str(tool.Project.get_parent_library(project_library).id())
+        if parent_library := tool.Project.get_parent_library(project_library):
+            self.parent_library = str(parent_library.id())
         ProjectLibraryData.load()  # Show edit icon in enum.
         return
 
@@ -259,6 +260,11 @@ class Link(PropertyGroup):
         description="STEP ID of the IfcDocumentReference when linked to a parent IFC project. Zero when no parent IFC exists",
         default=0,
     )
+    query: StringProperty(
+        name="Query",
+        description="Selector query used to filter elements when loading the linked model",
+        default="",
+    )
 
     if TYPE_CHECKING:
         name: str
@@ -274,6 +280,7 @@ class Link(PropertyGroup):
         include_in_drawings: bool
         empty_handle: Union[bpy.types.Object, None]
         ifc_definition_id: int
+        query: str
 
 
 class EditedObj(PropertyGroup):
@@ -295,6 +302,28 @@ class LibraryBreadcrumb(PropertyGroup):
         library_id: int
 
 
+class PendingOpeningRecut(PropertyGroup):
+    """One element whose ``HasOpenings`` exceeded ``void_limit`` at load time
+    and was imported without opening subtractions. The user can later apply
+    them on demand from the Project panel banner."""
+
+    ifc_definition_id: IntProperty(name="IFC Definition ID")
+
+    if TYPE_CHECKING:
+        ifc_definition_id: int
+
+
+class PendingArrayRepair(PropertyGroup):
+    """One array parent whose ``BBIM_Array.Data`` references at least one
+    child GUID that does not resolve in the current IFC file. The user can
+    select these parents from the Project panel banner to inspect them."""
+
+    ifc_definition_id: IntProperty(name="IFC Definition ID")
+
+    if TYPE_CHECKING:
+        ifc_definition_id: int
+
+
 class BIMProjectProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing", default=False)
     is_loading: BoolProperty(name="Is Loading", default=False)
@@ -360,6 +389,8 @@ class BIMProjectProperties(PropertyGroup):
         default=30,
         description="Maxium number of openings that object can have. If object has more openings, it will be loaded without openings",
     )
+    pending_opening_recut: CollectionProperty(name="Pending Opening Recut", type=PendingOpeningRecut)
+    pending_array_repair: CollectionProperty(name="Pending Array Repair", type=PendingArrayRepair)
     style_limit: IntProperty(
         name="Style Limit",
         default=300,
@@ -525,6 +556,8 @@ class BIMProjectProperties(PropertyGroup):
         deflection_tolerance: float
         angular_tolerance: float
         void_limit: int
+        pending_opening_recut: bpy.types.bpy_prop_collection_idprop[PendingOpeningRecut]
+        pending_array_repair: bpy.types.bpy_prop_collection_idprop[PendingArrayRepair]
         style_limit: int
         distance_limit: float
         false_origin_mode: Literal["AUTOMATIC", "MANUAL", "DISABLED"]

src/bonsai/bonsai/bim/module/spatial/decorator.py

@@ -18,43 +18,17 @@
 
 import blf
 import gpu
-from bpy.types import SpaceView3D
 from bpy_extras.view3d_utils import location_3d_to_region_2d
-from gpu_extras.batch import batch_for_shader
 from mathutils import Vector
 
 import bonsai.tool as tool
 
 
-class GridDecorator:
-    is_installed = False
-    handlers = []
-
-    @classmethod
-    def install(cls, context):
-        if cls.is_installed:
-            cls.uninstall()
-        handler = cls()
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw_text, (context,), "WINDOW", "POST_PIXEL"))
-        cls.handlers.append(SpaceView3D.draw_handler_add(handler.draw, (context,), "WINDOW", "POST_VIEW"))
-        cls.is_installed = True
-
-    @classmethod
-    def uninstall(cls):
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
-    def draw_batch(self, shader_type, content_pos, color, indices=None):
-        if not tool.Blender.validate_shader_batch_data(content_pos, indices):
-            return
-        shader = self.line_shader if shader_type == "LINES" else self.shader
-        batch = batch_for_shader(shader, shader_type, {"pos": content_pos}, indices=indices)
-        shader.uniform_float("color", color)
-        batch.draw(shader)
+class GridDecorator(tool.Blender.ViewportDecorator):
+    draw_methods = (
+        ("draw_text", "POST_PIXEL"),
+        ("draw", "POST_VIEW"),
+    )
 
     def draw_text(self, context):
         if not tool.Blender.is_addon_enabled():

src/bonsai/bonsai/bim/module/structural/decorator.py

@@ -31,11 +31,17 @@ import bonsai.tool as tool
 from bonsai.bim.module.structural.load_decoration_data import ShaderInfo
 
 
-class LoadsDecorator:
+class LoadsDecorator(tool.Blender.ViewportDecorator):
     """Decorator to show structural loads in 3D"""
 
-    is_installed = False
-    handlers = []
+    # draw_methods exists to satisfy ViewportDecorator.__init_subclass__'s
+    # method-existence check; the override install below is what actually
+    # registers handlers (the POST_VIEW binding passes no context arg, which
+    # the base's generic install cannot express).
+    draw_methods = (
+        ("draw_load_values", "POST_PIXEL"),
+        ("__call__", "POST_VIEW"),
+    )
     decoration_data = None
     text_info = []
     shader_info = []
@@ -54,15 +60,6 @@ class LoadsDecorator:
         cls.update()
         cls.is_installed = True
 
-    @classmethod
-    def uninstall(cls) -> None:
-        for handler in cls.handlers:
-            try:
-                SpaceView3D.draw_handler_remove(handler, "WINDOW")
-            except ValueError:
-                pass
-        cls.is_installed = False
-
     @classmethod
     def update(cls) -> None:
         cls.decoration_data.update()

src/bonsai/bonsai/bim/module/structural/load_decoration_data.py

@@ -71,7 +71,11 @@ class LoadByDirection(TypedDict):
 
 ProcessedLoad = TypedDict(
     "ProcessedLoad",
-    {"linear loads": LoadByDirection, "max linear load": float, "discrete loads": list[list[DiscreteConfigItem]]},
+    {
+        "linear loads": dict[str, LoadByDirection] | None,
+        "max linear load": float,
+        "discrete loads": list[list[DiscreteConfigItem]],
+    },
 )
 
 
@@ -845,13 +849,16 @@ class ShaderInfo:
         v = l1[1] + fac * (pos - l1[0])
         return v
 
-    def interpolate(self, pos: float, loadinfo: list[LoadConfigItem], start: int, end: int, key: str) -> np.ndarray:
+    def interpolate(self, pos: float, loadinfo: list[LoadConfigItem], start: int, end: int) -> np.ndarray:
         """interpolate the result vectors between load poits"""
         result = np.zeros(6)
         for i in range(6):
-            value1 = [loadinfo[start]["pos"], loadinfo[start][key][i]]  # [position, force_component]
-            value2 = [loadinfo[end]["pos"], loadinfo[end][key][i]]  #      [position, force_component]
-            result[i] = self.interp1d(value1, value2, pos)  #             interpolated [position, force_component]
+            # [position, force_component]
+            value1 = [loadinfo[start]["pos"], loadinfo[start]["load values"][i]]
+            # [position, force_component]
+            value2 = [loadinfo[end]["pos"], loadinfo[end]["load values"][i]]
+            # interpolated [position, force_component]
+            result[i] = self.interp1d(value1, value2, pos)
         return result
 
     def get_before_and_after(self, pos: float, load_config_list: list[list[LoadConfigItem]]) -> dict[str, list[float]]:
@@ -895,8 +902,8 @@ class ShaderInfo:
                         load_before += config[end]["load values"]
 
                 elif end - start == 1:
-                    load_before += self.interpolate(pos, config, start, end, "load values")
-                    load_after += self.interpolate(pos, config, start, end, "load values")
+                    load_before += self.interpolate(pos, config, start, end)
+                    load_after += self.interpolate(pos, config, start, end)
                 start += 1
                 end -= 1
         return_value = {"before": load_before.tolist(), "after": load_after.tolist()}

src/bonsai/bonsai/bim/module/style/operator.py

@@ -744,7 +744,7 @@ class EnableEditingSurfaceStyle(bpy.types.Operator):
         if self.ifc_class == "IfcSurfaceStyleLighting":
 
             def callback(attribute_name: str, _: object, data: dict[str, Any]) -> None:
-                assert attributes
+                assert attributes is not None
                 color = attributes.add()
                 assert isinstance(color, ColourRgb)
                 color.name = attribute_name
@@ -782,34 +782,40 @@ class EditSurfaceStyle(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context):
         self.props = tool.Style.get_style_props()
         self.style = tool.Ifc.get().by_id(self.props.is_editing_style)
+        prev_update_graph = self.props.update_graph
+        self.props["update_graph"] = False
 
-        style_elements = tool.Style.get_style_elements(self.style)
-        # NOTE: currently this operator is used to edit existing (and only existing) IfcSurfaceStyles
-        # or new or existing IfcSurfaceStyle components (shading, etc)
-        # which is kind of confusing.
-        if self.props.is_editing_class == "IfcSurfaceStyle":
-            self.surface_style = self.style
-        else:
-            self.surface_style = style_elements.get(self.props.is_editing_class, None)
-            self.shading_style = style_elements.get("IfcSurfaceStyleShading", None)
-            self.rendering_style = style_elements.get("IfcSurfaceStyleRendering", None)
-            self.texture_style = style_elements.get("IfcSurfaceStyleWithTextures", None)
+        try:
+            style_elements = tool.Style.get_style_elements(self.style)
 
-        if self.surface_style:
-            result = self.edit_existing_style()
-        else:
-            result = self.add_new_style()
+            # NOTE: currently this operator is used to edit existing (and only existing) IfcSurfaceStyles
+            # or new or existing IfcSurfaceStyle components (shading, etc)
+            # which is kind of confusing.
+            if self.props.is_editing_class == "IfcSurfaceStyle":
+                self.surface_style = self.style
+            else:
+                self.surface_style = style_elements.get(self.props.is_editing_class, None)
+                self.shading_style = style_elements.get("IfcSurfaceStyleShading", None)
+                self.rendering_style = style_elements.get("IfcSurfaceStyleRendering", None)
+                self.texture_style = style_elements.get("IfcSurfaceStyleWithTextures", None)
 
-        if result:
-            return result
+            if self.surface_style:
+                result = self.edit_existing_style()
+            else:
+                result = self.add_new_style()
 
-        tool.Style.disable_editing()
-        core.load_styles(tool.Style, style_type=self.props.style_type)
+            if result:
+                return result
 
-        # restore selected style type
-        material = tool.Ifc.get_object(self.style)
-        msprops = tool.Style.get_material_style_props(material)
-        msprops.active_style_type = msprops.active_style_type
+            tool.Style.disable_editing()
+            core.load_styles(tool.Style, style_type=self.props.style_type)
+
+            # restore selected style type
+            material = tool.Ifc.get_object(self.style)
+            msprops = tool.Style.get_material_style_props(material)
+            msprops.active_style_type = msprops.active_style_type
+        finally:
+            self.props["update_graph"] = prev_update_graph
 
     def edit_existing_style(self) -> None:
         ifc_file = tool.Ifc.get()
@@ -1231,4 +1237,5 @@ class RemoveSurfaceStyle(bpy.types.Operator, tool.Ifc.Operator):
         surface_style = tool.Style.get_style_elements(style)[props.is_editing_class]
         ifcopenshell.api.style.remove_surface_style(ifc_file, surface_style)
         core.disable_editing_style(tool.Style)
+        core.load_styles(tool.Style, style_type=props.style_type)
         return {"FINISHED"}

src/bonsai/bonsai/bim/module/style/prop.py

@@ -185,6 +185,13 @@ class ColourRgb(PropertyGroup):
     # to fit blender.bim.helper.draw_attribute
     is_optional = False
     special_type = ""
+    data_type = ""
+    ifc_class = ""
+    use_explorer_ui = False
+
+    @property
+    def display_name(self):
+        return self.name
 
     def get_value_name(self, *args, **kwargs):
         return "color_value"

src/bonsai/bonsai/bim/module/style/ui.py

@@ -176,8 +176,30 @@ class BIM_PT_styles(Panel):
         row.prop(self.props, "reflectance_method")
 
         if self.props.reflectance_method not in ("PHYSICAL", "NOTDEFINED", "FLAT"):
-            self.layout.label(text="Supported reflectance methods are:")
-            self.layout.label(text="PHYSICAL / NOTDEFINED / FLAT")
+            self.layout.label(
+                text=f"{self.props.reflectance_method} will be skipped: only PHYSICAL / NOTDEFINED / FLAT are supported",
+                icon="ERROR",
+            )
+        elif self.props.reflectance_method in ("PHYSICAL", "NOTDEFINED"):
+            if self.props.specular_colour_class == "IfcColourRgb":
+                self.layout.label(
+                    text="Metallic color is IFC-only in PHYSICAL/NOTDEFINED and does not affect Blender appearance",
+                    icon="ERROR",
+                )
+        elif self.props.reflectance_method == "FLAT":
+            if self.props.diffuse_colour_class == "IfcNormalisedRatioMeasure":
+                self.layout.label(
+                    text="Emissive ratio is IFC-only in FLAT Reflectance method and does not affect Blender appearance",
+                    icon="ERROR",
+                )
+            self.layout.label(
+                text="Specular value is IFC-only in FLAT Reflectance method and does not affect Blender appearance",
+                icon="ERROR",
+            )
+            self.layout.label(
+                text="Highlight value is IFC-only in FLAT Reflectance method and does not affect Blender appearance",
+                icon="ERROR",
+            )
 
         row = self.layout.row(align=True)
         row.label(text="Emissive" if self.props.reflectance_method == "FLAT" else "Diffuse")
@@ -232,6 +254,8 @@ class BIM_PT_styles(Panel):
         row.operator("bim.add_surface_texture", text="", icon="ADD")
         if textures:
             self.layout.prop(self.props, "uv_mode")
+            if self.props.uv_mode in ("Generated", "Camera"):
+                self.layout.label(text="Not available in SOLID Mode", icon="INFO")
 
         for i, texture in enumerate(textures):
             split = self.layout.split(factor=0.30, align=True)
@@ -244,6 +268,22 @@ class BIM_PT_styles(Panel):
             op_clear = row.operator("bim.remove_texture_map", text="", icon="X")
             op_path.texture_map_index = op_clear.texture_map_index = i
 
+            reflectance = self.props.reflectance_method
+            mode = texture.mode
+            if reflectance == "FLAT":
+                if mode != "EMISSIVE":
+                    self.layout.label(
+                        text=f"{mode} will be skipped: only EMISSIVE is supported for Render Reflectance FLAT",
+                        icon="ERROR",
+                    )
+            elif reflectance in ("PHYSICAL", "NOTDEFINED"):
+                _SUPPORTED = {"DIFFUSE", "NORMAL", "METALLICROUGHNESS", "EMISSIVE", "OCCLUSION"}
+                if mode not in _SUPPORTED:
+                    self.layout.label(
+                        text=f"{mode} will be skipped: not supported for Render Reflectance PHYSICAL/NOTDEFINED",
+                        icon="ERROR",
+                    )
+
     def draw_externally_defined_surface_style(self):
         row = self.layout.row()
         op = row.operator("bim.browse_external_style", icon="APPEND_BLEND", text="Append From Blend File")
@@ -252,10 +292,17 @@ class BIM_PT_styles(Panel):
         bonsai.bim.helper.draw_attributes(self.props.external_style_attributes, self.layout, enable_search=True)
 
     def draw_refraction_surface_style(self):
+        self.layout.label(
+            text="Refraction values are IFC-only and do not affect Blender surface appearance",
+            icon="ERROR",
+        )
         bonsai.bim.helper.draw_attributes(self.props.refraction_style_attributes, self.layout, enable_search=True)
-        row = self.layout.row(align=True)
 
     def draw_lighting_surface_style(self):
+        self.layout.label(
+            text="Lighting values are IFC-only and do not affect Blender surface appearance",
+            icon="ERROR",
+        )
         bonsai.bim.helper.draw_attributes(self.props.lighting_style_colours, self.layout)
 
     def draw_edit_ui(self, edit_label: str):

src/bonsai/bonsai/bim/module/system/decorator.py

@@ -15,9 +15,10 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was modified with the assistance of an AI coding tool.
 
 
-import bmesh
 import bpy
 import gpu
 from bpy.app.handlers import persistent
@@ -30,12 +31,6 @@ ERROR_ELEMENTS_COLOR = (1, 0.2, 0.322, 1)  # RED
 UNSPECIAL_ELEMENT_COLOR = (0.2, 0.2, 0.2, 1)  # GREY
 
 
-def transparent_color(color, alpha=0.1):
-    color = [i for i in color]
-    color[3] = alpha
-    return color
-
-
 @persistent
 def toggle_decorations_on_load(*args):
     props = tool.System.get_system_props()
@@ -78,15 +73,9 @@ class SystemDecorator:
         batch.draw(shader)
 
     def draw_faces(self, bm, vertices_coords):
-        """mutates original bm (triangulates it)
-        so the triangulation edges will be shown too
-        """
-        traingulated_bm = bm
-        bmesh.ops.triangulate(traingulated_bm, faces=traingulated_bm.faces)
-
-        face_indices = [[v.index for v in f.verts] for f in traingulated_bm.faces]
-        faces_color = transparent_color(self.addon_prefs.decorator_color_special)
-        self.draw_batch("TRIS", vertices_coords, faces_color, face_indices)
+        """Submit a non-mutating beauty-triangulated TRIS batch over ``bm``'s faces."""
+        faces_color = tool.Blender.transparent_color(self.addon_prefs.decorator_color_special)
+        tool.Blender.draw_bmesh_face_tris(bm, vertices_coords, faces_color, self.draw_batch)
 
     def __call__(self, context, get_custom_bmesh=None, draw_faces=False, exit_edit_mode_callback=None):
         self.addon_prefs = tool.Blender.get_addon_preferences()
@@ -133,13 +122,15 @@ class SystemDecorator:
         self.shader = gpu.shader.from_builtin("UNIFORM_COLOR")
         self.shader.bind()
 
-        self.draw_batch("LINES", all_vertices, transparent_color(unselected_elements_color), unselected_edges)
+        self.draw_batch(
+            "LINES", all_vertices, tool.Blender.transparent_color(unselected_elements_color), unselected_edges
+        )
         self.draw_batch("LINES", all_vertices, selected_elements_color, selected_edges)
         self.draw_batch("LINES", all_vertices, UNSPECIAL_ELEMENT_COLOR, arc_edges)
         self.draw_batch("LINES", all_vertices, special_elements_color, preview_edges)
         self.draw_batch("LINES", all_vertices, special_elements_color, roof_angle_edges)
 
-        self.draw_batch("POINTS", unselected_vertices, transparent_color(unselected_elements_color, 0.5))
+        self.draw_batch("POINTS", unselected_vertices, tool.Blender.transparent_color(unselected_elements_color, 0.5))
         self.draw_batch("POINTS", error_vertices, ERROR_ELEMENTS_COLOR)
         self.draw_batch("POINTS", special_vertices, special_elements_color)
         self.draw_batch("POINTS", selected_vertices, selected_elements_color)

src/bonsai/bonsai/bim/module/system/operator.py

@@ -317,13 +317,23 @@ class MEPConnectElements(bpy.types.Operator, tool.Ifc.Operator):
     bl_label = "Connect MEP Elements"
     bl_description = "Connects two selected elements by their closest located ports and adjusts them"
     bl_options = {"REGISTER", "UNDO"}
-    obj1_name: bpy.props.StringProperty(name="Object 1")
-    obj2_name: bpy.props.StringProperty(name="Object 2")
+    obj1_guid: bpy.props.StringProperty(name="Object 1 GlobalId")
+    obj2_guid: bpy.props.StringProperty(name="Object 2 GlobalId")
 
     def _execute(self, context):
-        if self.obj1_name and self.obj2_name:
-            obj1 = bpy.data.objects.get(self.obj1_name)
-            obj2 = bpy.data.objects.get(self.obj2_name)
+        if self.obj1_guid and self.obj2_guid:
+            ifc_file = tool.Ifc.get()
+            try:
+                el1_lookup = ifc_file.by_guid(self.obj1_guid)
+                el2_lookup = ifc_file.by_guid(self.obj2_guid)
+            except RuntimeError:
+                self.report({"ERROR"}, "Could not resolve MEP elements from supplied GlobalIds.")
+                return {"CANCELLED"}
+            obj1 = tool.Ifc.get_object(el1_lookup)
+            obj2 = tool.Ifc.get_object(el2_lookup)
+            if not obj1 or not obj2:
+                self.report({"ERROR"}, "Supplied MEP elements have no Blender object bound.")
+                return {"CANCELLED"}
         else:
             if not context.selected_objects or len(context.selected_objects) != 2:
                 self.report({"ERROR"}, "Need to select 2 objects.")

src/bonsai/bonsai/bim/module/type/operator.py

@@ -65,10 +65,28 @@ class AssignType(bpy.types.Operator, tool.Ifc.Operator):
             if active_drawing:
                 active_target_view = tool.Drawing.get_drawing_target_view(active_drawing)
 
+        compatible: list[tuple[bpy.types.Object, ifcopenshell.entity_instance]] = []
+        skipped_classes: set[str] = set()
         for obj in related_objects:
             element = tool.Ifc.get_entity(obj)
             if not element or not element.is_a("IfcObject"):
                 continue
+            if not tool.Type.is_relating_type_compatible(element, relating_type):
+                skipped_classes.add(element.is_a())
+                continue
+            compatible.append((obj, element))
+
+        if skipped_classes:
+            self.report(
+                {"WARNING"},
+                f"Skipped {', '.join(sorted(skipped_classes))}: not a valid occurrence for " f"{relating_type.is_a()}.",
+            )
+
+        if not compatible:
+            self.report({"ERROR"}, f"No selected object can be typed by {relating_type.is_a()}.")
+            return {"CANCELLED"}
+
+        for obj, element in compatible:
             core.assign_type(tool.Ifc, tool.Model, tool.Type, element=element, type=relating_type)
 
             # Switch to the drawing's target view if available
@@ -376,12 +394,22 @@ class DuplicateType(bpy.types.Operator, tool.Ifc.Operator):
         if self.assign_selected_objects:
             selected_objects = tool.Blender.get_selected_objects()
             prefs = tool.Blender.get_addon_preferences()
+            skipped_classes: set[str] = set()
             for selected_obj in selected_objects:
                 selected_element = tool.Ifc.get_entity(selected_obj)
-                if selected_element and selected_element.is_a("IfcObject"):
-                    core.assign_type(tool.Ifc, tool.Model, tool.Type, element=selected_element, type=new)
-                    if prefs.occurrence_name_style == "TYPE":
-                        selected_obj.name = tool.Model.generate_occurrence_name(new, selected_element.is_a())
+                if not selected_element or not selected_element.is_a("IfcObject"):
+                    continue
+                if not tool.Type.is_relating_type_compatible(selected_element, new):
+                    skipped_classes.add(selected_element.is_a())
+                    continue
+                core.assign_type(tool.Ifc, tool.Model, tool.Type, element=selected_element, type=new)
+                if prefs.occurrence_name_style == "TYPE":
+                    selected_obj.name = tool.Model.generate_occurrence_name(new, selected_element.is_a())
+            if skipped_classes:
+                self.report(
+                    {"WARNING"},
+                    f"Skipped {', '.join(sorted(skipped_classes))}: not a valid occurrence for " f"{new.is_a()}.",
+                )
 
         if obj in context.selectable_objects:
             tool.Blender.select_and_activate_single_object(context, new_obj)

src/bonsai/bonsai/bim/module/void/operator.py

@@ -26,7 +26,7 @@ import bonsai.bim.handler
 import bonsai.core.geometry
 import bonsai.core.root
 import bonsai.tool as tool
-from bonsai.bim.module.model.opening import FilledOpeningGenerator
+from bonsai.bim.module.model.opening import FilledOpeningGenerator, is_filling_supported
 
 
 class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
@@ -34,11 +34,13 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
     bl_label = "Apply Opening"
     bl_options = {"REGISTER", "UNDO"}
     bl_description = (
-        "Apply opening objects to an Element.\n\n"
-        "The Element and the openings to be applied should be selected. The order of selection is not important.\n"
-        "Opening can be just a Blender mesh object.\n\n"
-        "Shift+click: keep the filling at its current matrix_world — skip the wall-axis snap "
-        "and the rl1/rl2 Z-elevation default that the regular click applies."
+        "Cuts openings in a wall, slab, or roof using selected shape objects — "
+        "doors, windows, existing openings, or plain (non-IFC) meshes. "
+        "Selection order doesn't matter.\n\n"
+        "Doors and windows also fill the opening. Other IFC classes are currently "
+        "unsupported by the opening generator and get skipped with a warning.\n\n"
+        "Shift+click: keep each opening at its shape object's current position "
+        "instead of snapping to the wall."
     )
 
     # Toggled by ``invoke`` when the user holds SHIFT during a gizmo / hotkey
@@ -59,6 +61,12 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
         return self.execute(context)
 
     def _execute(self, context):
+        # Multi-opening drops on the same host fan out N update_representation
+        # writes + N switch_representation recuts without batching. Coalesce.
+        with tool.Geometry.batch_host_recut():
+            return self._add_openings(context)
+
+    def _add_openings(self, context):
         selected_objects = context.selected_objects
         target_object = selected_objects[0]
 
@@ -78,8 +86,14 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
                     self.report({"INFO"}, "You can't add an opening to another opening.")
                     continue
                 elif not element1.is_a("IfcOpeningElement") and not element2.is_a("IfcOpeningElement"):
-                    if element1.is_a("IfcWindow") or element1.is_a("IfcDoor"):  # Add a fill to an element.
+                    if is_filling_supported(element1):  # Add a fill to an element.
                         obj1, obj2 = obj2, obj1
+                    elif not is_filling_supported(element2):
+                        self.report(
+                            {"INFO"},
+                            f"Cannot apply {element2.is_a()} as an opening — Bonsai currently supports only IfcDoor and IfcWindow as parametric fillings.",
+                        )
+                        continue
                     FilledOpeningGenerator().generate(
                         obj2,
                         obj1,
@@ -165,7 +179,7 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
                             voided_obj.scale = (1.0, 1.0, 1.0)
                             tool.Ifc.finish_edit(voided_obj)
                         else:
-                            bpy.ops.bim.update_representation(obj=voided_obj.name)
+                            tool.Geometry.update_host_representation(voided_obj)
 
                     if tool.Ifc.is_moved(voided_obj):
                         bonsai.core.geometry.edit_object_placement(
@@ -174,12 +188,7 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
 
                     representation = tool.Geometry.get_active_representation(voided_obj)
                     assert representation
-                    bonsai.core.geometry.switch_representation(
-                        tool.Ifc,
-                        tool.Geometry,
-                        obj=voided_obj,
-                        representation=representation,
-                    )
+                    tool.Geometry.recut_host(voided_obj, representation)
                 tool.Geometry.lock_scale(voided_obj)
 
             if not has_visible_openings:
@@ -217,12 +226,7 @@ class RemoveOpening(bpy.types.Operator, tool.Ifc.Operator):
             if building_obj and building_obj.data:
                 representation = tool.Geometry.get_active_representation(building_obj)
                 assert representation
-                bonsai.core.geometry.switch_representation(
-                    tool.Ifc,
-                    tool.Geometry,
-                    obj=building_obj,
-                    representation=representation,
-                )
+                tool.Geometry.recut_host(building_obj, representation)
         tool.Geometry.unlock_scale_object_with_openings(obj)
         tool.Geometry.clear_cache(element)
         return {"FINISHED"}

src/bonsai/bonsai/bim/ui.py

@@ -39,21 +39,10 @@ from natsort import natsorted
 import bonsai.bim
 import bonsai.bim.helper
 import bonsai.tool as tool
+from bonsai.bim.ifc import is_cache_locked_by_other_process
 from bonsai.bim.module.bsdd.prop import BIMBSDDProperties, BSDDProperty
-from bonsai.bim.module.model.prop import (
-    BIMDoorProperties,
-    BIMRailingProperties,
-    BIMRoofProperties,
-    BIMStairProperties,
-    BIMWindowProperties,
-)
-from bonsai.bim.module.model.ui import (
-    draw_door_properties,
-    draw_railing_properties,
-    draw_roof_properties,
-    draw_stair_properties,
-    draw_window_properties,
-)
+from bonsai.bim.module.model import prop as _model_prop
+from bonsai.bim.module.model import ui as _model_ui
 from bonsai.bim.module.pset.prop import IfcProperty
 from bonsai.bim.prop import Attribute
 
@@ -278,30 +267,29 @@ class BIM_UL_panel_visibilities(bpy.types.UIList):
 class GizmoPreferences(bpy.types.PropertyGroup):
     """Aggregator for parametric gizmo visibility settings. One flat bool per
     parametric feature; controls whether that feature's gizmo group polls
-    visible in the viewport."""
+    visible in the viewport.
+
+    The per-feature ``<name>: BoolProperty`` fields are derived from
+    ``tool.Parametric.EDIT_TYPES`` at module load — adding a new parametric
+    type to the registry automatically surfaces its toggle here, with no
+    parallel hand-maintained list to keep in sync."""
 
     draw_gizmos_in_3d_viewport: BoolProperty(
         name="Draw Gizmos In 3D Viewport",
         default=True,
         description="Show interactive gizmos in the 3D viewport for parametric elements",
     )
-    door: BoolProperty(name="Door", default=True)
-    window: BoolProperty(name="Window", default=True)
-    stair: BoolProperty(name="Stair", default=True)
-    railing: BoolProperty(name="Railing", default=True)
-    roof: BoolProperty(name="Roof", default=True)
-    array: BoolProperty(name="Array", default=True)
-    wall: BoolProperty(name="Wall", default=True)
 
     if TYPE_CHECKING:
         draw_gizmos_in_3d_viewport: bool
-        door: bool
-        window: bool
-        stair: bool
-        railing: bool
-        roof: bool
-        array: bool
-        wall: bool
+
+
+for _gizmo_pref_entry in tool.Parametric.EDIT_TYPES:
+    GizmoPreferences.__annotations__[_gizmo_pref_entry.name] = BoolProperty(
+        name=_gizmo_pref_entry.name.replace("_", " ").title(),
+        default=True,
+    )
+del _gizmo_pref_entry
 
 
 class DocPreferences(bpy.types.PropertyGroup):
@@ -397,11 +385,22 @@ class DocPreferences(bpy.types.PropertyGroup):
 
 
 class DefaultParameters(bpy.types.PropertyGroup):
-    door: bpy.props.PointerProperty(type=BIMDoorProperties)
-    window: bpy.props.PointerProperty(type=BIMWindowProperties)
-    railing: bpy.props.PointerProperty(type=BIMRailingProperties)
-    roof: bpy.props.PointerProperty(type=BIMRoofProperties)
-    stair: bpy.props.PointerProperty(type=BIMStairProperties)
+    """Per-type preset values used to seed new parametric instances.
+
+    The ``<name>: PointerProperty`` fields are derived from the subset of
+    ``tool.Parametric.EDIT_TYPES`` flagged ``has_default_parameters=True``,
+    each pointing at the matching ``BIM<Name>Properties`` class. Adding a
+    new entry with that flag automatically surfaces a preferences section
+    and gives the create operator a preset to copy from."""
+
+
+for _default_params_entry in tool.Parametric.EDIT_TYPES:
+    if not _default_params_entry.has_default_parameters:
+        continue
+    DefaultParameters.__annotations__[_default_params_entry.name] = bpy.props.PointerProperty(
+        type=getattr(_model_prop, _default_params_entry.props_attr),
+    )
+del _default_params_entry
 
 
 class BIM_ADDON_preferences(bpy.types.AddonPreferences):
@@ -513,6 +512,15 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
         size=4,
         description="Color of not selected verts/edges (used in profile editing mode)",
     )
+    clip_box_cap_color: bpy.props.FloatVectorProperty(
+        name="Clip Box Caps Color",
+        subtype="COLOR",
+        default=(0.0, 0.0, 0.0, 1.0),
+        min=0.0,
+        max=1.0,
+        size=4,
+        description="Fill color of clip-box cross-section caps",
+    )
     decorator_color_special: bpy.props.FloatVectorProperty(
         name="Special Elements Color",
         subtype="COLOR",
@@ -569,6 +577,43 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
     should_disable_undo_on_save: BoolProperty(
         name="Disable Undo When Saving (Faster saves, no undo for you!)", default=False
     )
+
+    def update_autosave_settings(self, context: bpy.types.Context) -> None:
+        if self.autosave_enabled:
+            tool.Autosave.reset_timer()
+        else:
+            tool.Autosave.cancel_timer()
+
+    autosave_enabled: BoolProperty(
+        name="Enable IFC Autosave Timer",
+        description="Periodically remind you to save or automatically create a backup copy of the IFC file",
+        default=False,
+        update=update_autosave_settings,
+    )
+    autosave_interval_minutes: bpy.props.IntProperty(
+        name="Autosave Interval (Minutes)",
+        description="Time between autosave reminders or backups. The timer resets whenever you open or save a project",
+        default=10,
+        min=1,
+        max=1440,
+        update=update_autosave_settings,
+    )
+    autosave_mode: bpy.props.EnumProperty(
+        name="Autosave Mode",
+        items=[
+            (
+                "PROMPT",
+                "Prompt to Save",
+                "Show a dialog offering to save the IFC project when the timer expires",
+            ),
+            (
+                "BACKUP",
+                "Automatic Backup",
+                "Save a backup copy as filename_autosaved.ifc when the timer expires",
+            ),
+        ],
+        default="PROMPT",
+    )
     should_stream: BoolProperty(name="Stream Data From IFC-SPF (Only for advanced users)", default=False)
     should_always_cache: BoolProperty(
         name="Always Cache Geometry",
@@ -681,6 +726,9 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
         bsdd_load_test_dictionaries: bool
         bsdd_baseurl: str
         should_disable_undo_on_save: bool
+        autosave_enabled: bool
+        autosave_interval_minutes: int
+        autosave_mode: Literal["PROMPT", "BACKUP"]
         should_stream: bool
         should_always_cache: bool
         occurrence_name_style: Literal["CLASS", "TYPE", "CUSTOM"]
@@ -802,43 +850,39 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
         layout.row().prop(self, "decorator_color_special")
         layout.row().prop(self, "decorator_color_error")
         layout.row().prop(self, "decorator_color_background")
+        bonsai.bim.helper.draw_expandable_panel(
+            layout,
+            context,
+            "Clip Box",
+            self.draw_clip_box_colors,
+        )
+
+    def draw_clip_box_colors(self, layout: bpy.types.UILayout, context: bpy.types.Context) -> None:
+        layout.row().prop(self, "clip_box_cap_color")
 
     def draw_default_parameters(self, layout: bpy.types.UILayout, context: bpy.types.Context) -> None:
         box = layout.box()
-        bonsai.bim.helper.draw_expandable_panel(
-            box,
-            context,
-            "Door",
-            lambda _layout, _context: draw_door_properties(_layout, self.default_parameters.door),
-        )
-        bonsai.bim.helper.draw_expandable_panel(
-            box,
-            context,
-            "Window",
-            lambda _layout, _context: draw_window_properties(_layout, self.default_parameters.window),
-        )
-        bonsai.bim.helper.draw_expandable_panel(
-            box,
-            context,
-            "Railing",
-            lambda _layout, _context: draw_railing_properties(_layout, self.default_parameters.railing),
-        )
-        bonsai.bim.helper.draw_expandable_panel(
-            box,
-            context,
-            "Roof",
-            lambda _layout, _context: draw_roof_properties(_layout, self.default_parameters.roof),
-        )
-        bonsai.bim.helper.draw_expandable_panel(
-            box,
-            context,
-            "Stair",
-            lambda _layout, _context: draw_stair_properties(_layout, self.default_parameters.stair),
-        )
+        for entry in tool.Parametric.EDIT_TYPES:
+            if not entry.has_default_parameters:
+                continue
+            props = getattr(self.default_parameters, entry.name)
+            draw_props = getattr(_model_ui, f"draw_{entry.name}_properties")
+            bonsai.bim.helper.draw_expandable_panel(
+                box,
+                context,
+                entry.name.replace("_", " ").title(),
+                lambda _layout, _context, _draw=draw_props, _props=props: _draw(_layout, _props),
+            )
 
     def draw_other_settings(self, layout: bpy.types.UILayout, context: bpy.types.Context) -> None:
         layout.prop(self, "opening_focus_opacity")
         layout.prop(self, "should_disable_undo_on_save")
+        layout.separator()
+        layout.label(text="Autosave:")
+        layout.prop(self, "autosave_enabled")
+        if self.autosave_enabled:
+            layout.prop(self, "autosave_interval_minutes")
+            layout.prop(self, "autosave_mode")
         layout.prop(self, "should_stream")
         layout.prop(self, "should_always_cache")
         layout.label(text="bSDD:")
@@ -952,6 +996,50 @@ class BIM_PT_tabs(Panel):
             op.uri = "https://docs.bonsaibim.org/guides/troubleshooting.html#saving-and-loading-blend-files"
             row.operator("bim.close_blend_warning", text="", icon="CANCEL")
 
+        if is_cache_locked_by_other_process():
+            box = self.layout.box()
+            box.alert = True
+            row = box.row(align=True)
+            row.label(text="IFC Already Open in Another Blender Instance", icon="ERROR")
+            row.operator("bim.dismiss_multi_instance_warning", text="", icon="CANCEL")
+            draw_multiline_text(
+                box.column(align=True),
+                "This file is open in another Blender instance. Editing the same "
+                "IFC from two instances at once can lose your work or display "
+                "outdated geometry. Close the other Blender instances to continue safely.",
+                context=context,
+            )
+
+        pprops = tool.Project.get_project_props()
+        if pending := pprops.pending_opening_recut:
+            box = self.layout.box()
+            box.alert = True
+            box.label(text="Opening Cuts Skipped", icon="ERROR")
+            draw_multiline_text(
+                box.column(align=True),
+                f"{len(pending)} element(s) had too many openings to cut during load. "
+                f"Apply to recompute their meshes, or dismiss to leave them as they are.",
+                context=context,
+            )
+            row = box.row(align=True)
+            row.operator("bim.select_pending_opening_cuts", text="Select Elements", icon="RESTRICT_SELECT_OFF")
+            row.operator("bim.apply_pending_opening_cuts", text="Apply Openings", icon="PLAY")
+            row.operator("bim.dismiss_pending_opening_cuts", text="", icon="CANCEL")
+
+        if pending := pprops.pending_array_repair:
+            box = self.layout.box()
+            box.alert = True
+            box.label(text="Arrays With Missing Children", icon="ERROR")
+            draw_multiline_text(
+                box.column(align=True),
+                f"{len(pending)} array parent(s) reference child GUIDs that don't exist in this file. "
+                f"The arrays loaded incomplete. Select to inspect, or dismiss.",
+                context=context,
+            )
+            row = box.row(align=True)
+            row.operator("bim.select_pending_array_repair", text="Select Elements", icon="RESTRICT_SELECT_OFF")
+            row.operator("bim.dismiss_pending_array_repair", text="", icon="CANCEL")
+
         gprops = tool.Geometry.get_geometry_props()
         # Check that Blender mode and IFC Mode do match.
         if context.mode == "OBJECT" and gprops.mode in ("OBJECT", "ITEM"):
@@ -1903,6 +1991,7 @@ class BIM_PT_decorators_overlay(Panel):
         aggregate_props = tool.Aggregate.get_aggregate_props()
         nest_props = tool.Nest.get_nest_props()
         model_props = tool.Model.get_model_props()
+        system_props = tool.System.get_system_props()
         display_all = overlay.show_overlays
 
         col = layout.column()
@@ -1920,10 +2009,20 @@ class BIM_PT_decorators_overlay(Panel):
         row = col.row(align=True)
         row.prop(model_props, "show_slab_direction", text="Slab Direction")
         row = col.row(align=True)
+        row.prop(model_props, "show_paths", text="Element Paths")
+        row.prop(system_props, "should_draw_decorations", text="System Decorations")
+        row = col.row(align=True)
         row.prop(model_props, "show_bounding_box", text="Bounding Box Dimensions")
         row = col.row(align=True)
         row.prop(model_props, "show_cut_decorator", text="Cut Decorator")
         row.prop(model_props, "show_cut_decorator_fill", text="Fill Cut Decorator")
+        clip_box_props = tool.ClipBox.get_scene_props(context.scene)
+        row = col.row(align=True)
+        # Grey out the toggles when there is no clip box to act on, so the
+        # user can see the controls but can't flip a switch that does nothing.
+        row.enabled = bool(clip_box_props.clip_boxes)
+        row.prop(clip_box_props, "enabled", text="Enable Clipping")
+        row.prop(clip_box_props, "show_caps", text="Show Caps")
 
 
 class BIM_PT_snappping(Panel):

src/bonsai/bonsai/core/connection.py

@@ -0,0 +1,113 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Shared post-disconnect cleanup dispatch.
+
+Used by both ``bim.disconnect_elements`` (explicit user disconnect) and the
+connection cascade in ``tool.Geometry.delete_ifc_object`` (implicit
+disconnect-on-delete). Each kind returned by
+:py:meth:`bonsai.tool.connection.Connection.find_rels` /
+:py:meth:`find_rels_for_element` maps to a single arm here, so adding a new
+kind means extending one dispatch table — both call sites benefit
+automatically and the AST forward-compat guard enforces coverage.
+
+The ``subject`` parameter is the entity whose teardown effects the
+disconnect: for ``"path"`` / ``"element"`` / ``"element-top"`` kinds it
+carries an ``IfcRel*`` relationship entity (the rel that gets removed);
+for ``"mep-pair-fitting"`` it carries an ``IfcFlowFitting`` (the fitting
+that gets deleted). The slot is uniform on intent — the dispatch decides
+the teardown mechanism by kind.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import bonsai.core.geometry
+from bonsai.core.model import regenerate_wall_to_underside
+
+if TYPE_CHECKING:
+    import ifcopenshell
+
+    import bonsai.tool as tool
+
+
+def disconnect_rel(
+    ifc: type[tool.Ifc],
+    geometry: type[tool.Geometry],
+    model: type[tool.Model],
+    connection: type[tool.Connection],
+    subject: ifcopenshell.entity_instance,
+    kind: str,
+    elem: ifcopenshell.entity_instance,
+    partner: ifcopenshell.entity_instance,
+    skip_elem_recreate: bool = False,
+    skip_partner_recreate: bool = False,
+) -> None:
+    """Run the post-disconnect cleanup for one connection.
+
+    ``elem`` and ``partner`` are the two endpoints. The ``skip_*_recreate``
+    flags suppress per-side regenerate / recreate work — used by the
+    cascade-on-delete to avoid re-extruding entities that are about to be
+    removed by ``remove_product``. For the disconnect operator (where neither
+    endpoint is being deleted), both flags stay False and the full cleanup
+    runs on both sides.
+    """
+    if kind == "path":
+        bonsai.core.geometry.remove_connection(geometry, connection=subject)
+        if not skip_elem_recreate:
+            elem_obj = ifc.get_object(elem)
+            if elem_obj is not None:
+                model.recreate_wall(elem, elem_obj)
+        if not skip_partner_recreate:
+            partner_obj = ifc.get_object(partner)
+            if partner_obj is not None:
+                model.recreate_wall(partner, partner_obj)
+    elif kind == "element-top":
+        wall, _slab = connection.orient_element_top(subject, elem, partner)
+        ifc.run(
+            "geometry.disconnect_element",
+            relating_element=subject.RelatingElement,
+            related_element=subject.RelatedElement,
+        )
+        # Skip the wall-side regenerate when the wall is itself being deleted —
+        # either it's the elem of this cascade pass, or it's the partner that
+        # was queued earlier in the same batch.
+        if (wall is elem and skip_elem_recreate) or (wall is partner and skip_partner_recreate):
+            return
+        wall_obj = ifc.get_object(wall)
+        if wall_obj is not None:
+            regenerate_wall_to_underside(ifc, geometry, model, [wall_obj])
+    elif kind == "element":
+        ifc.run(
+            "geometry.disconnect_element",
+            relating_element=subject.RelatingElement,
+            related_element=subject.RelatedElement,
+        )
+    elif kind == "mep-pair-fitting":
+        if skip_elem_recreate and subject is elem:
+            return
+        if skip_partner_recreate and subject is partner:
+            return
+        fitting_obj = ifc.get_object(subject)
+        if fitting_obj is not None:
+            geometry.delete_ifc_object(fitting_obj)
+    else:
+        raise ValueError(f"Unknown kind: {kind!r}")

src/bonsai/bonsai/core/drawing.py

@@ -302,9 +302,15 @@ def add_drawing(
         context=drawing.get_body_context(),
         ifc_representation_class=None,
     )
+
+    drawings_parent_group = drawing.ensure_drawings_parent_group()
+
     group = ifc.run("group.add_group")
     ifc.run("group.edit_group", group=group, attributes={"Name": drawing_name, "ObjectType": "DRAWING"})
     ifc.run("group.assign_group", group=group, products=[element])
+
+    ifc.run("group.assign_group", group=drawings_parent_group, products=[group])
+
     collector.assign(camera)
     pset = ifc.run("pset.add_pset", product=element, name="EPset_Drawing")
     if drawing.get_unit_system() == "METRIC":
@@ -335,7 +341,10 @@ def add_drawing(
         },
     )
     drawing.setup_shading_styles_path(shading_styles_path)
-    information = ifc.run("document.add_information")
+
+    drawings_parent_document = drawing.ensure_drawings_parent_document()
+
+    information = ifc.run("document.add_information", parent=drawings_parent_document)
     uri = drawing.get_default_drawing_path(drawing_name)
     reference = ifc.run("document.add_reference", information=information)
     if ifc.get_schema() == "IFC2X3":
@@ -363,9 +372,13 @@ def duplicate_drawing(
     drawing_tool.set_name(new_drawing, drawing_name)
     group = drawing_tool.get_drawing_group(new_drawing)
     ifc.run("group.unassign_group", group=group, products=[new_drawing])
+
+    drawings_parent_group = drawing_tool.ensure_drawings_parent_group()
+
     new_group = ifc.run("group.add_group")
     ifc.run("group.edit_group", group=new_group, attributes={"Name": drawing_name, "ObjectType": "DRAWING"})
     ifc.run("group.assign_group", group=new_group, products=[new_drawing])
+    ifc.run("group.assign_group", group=drawings_parent_group, products=[new_group])
     if should_duplicate_annotations:
         new_annotations: list[ifcopenshell.entity_instance] = []
         annotation_objs = [ifc.get_object(a) for a in drawing_tool.get_group_elements(group) if a != drawing]
@@ -381,7 +394,9 @@ def duplicate_drawing(
     old_reference = drawing_tool.get_drawing_document(new_drawing)
     ifc.run("document.unassign_document", products=[new_drawing], document=old_reference)
 
-    information = ifc.run("document.add_information")
+    drawings_parent_document = drawing_tool.ensure_drawings_parent_document()
+
+    information = ifc.run("document.add_information", parent=drawings_parent_document)
     uri = drawing_tool.get_default_drawing_path(drawing_name)
     reference = ifc.run("document.add_reference", information=information)
     if ifc.get_schema() == "IFC2X3":

src/bonsai/bonsai/core/model.py

@@ -167,12 +167,22 @@ def regenerate_wall_to_underside(
     model: type[tool.Model],
     wall_objs: list[bpy.types.Object],
 ) -> None:
-    """Re-clip walls to their connected underside objects after the slab has moved."""
+    """Re-clip walls to their connected underside objects after the slab has moved.
+
+    When a wall has no remaining slab connections — the case reached after the
+    last TOP rel is severed (via disconnect or via cascade-on-slab-delete) — the
+    stale trim booleans are cleaned up so the wall reverts to its pre-clip
+    extrusion instead of holding orphan ``IfcBooleanResult`` items and a dead
+    ``BBIM_Boolean`` pset.
+    """
     clipped_objs = []
+    reverted_objs = []
     for obj in wall_objs:
         wall = ifc.get_entity(obj)
         slab_objs = model.get_connected_slab_objs(wall)
         if not slab_objs:
+            model.remove_wall_to_underside_booleans(wall)
+            reverted_objs.append(obj)
             continue
         if ifc.is_moved(obj):
             geometry.run_edit_object_placement(obj=obj)
@@ -185,8 +195,9 @@ def regenerate_wall_to_underside(
             if clip:
                 model.clip_wall_to_slab(wall, clip)
         clipped_objs.append(obj)
-    if clipped_objs:
-        model.reload_body_representation(clipped_objs)
+    refresh_objs = clipped_objs + reverted_objs
+    if refresh_objs:
+        model.reload_body_representation(refresh_objs)
 
 
 def extend_wall_to_slab(

src/bonsai/bonsai/core/product.py

@@ -1,64 +0,0 @@
-# Bonsai - OpenBIM Blender Add-on
-# Copyright (C) 2026
-#
-# This file is part of Bonsai.
-#
-# Bonsai is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Bonsai is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
-#
-# This file was generated with the assistance of an AI coding tool.
-
-from __future__ import annotations
-
-import math
-from collections.abc import Iterable
-from typing import TYPE_CHECKING
-
-import bonsai.core.geometry
-
-if TYPE_CHECKING:
-    import bpy
-
-    import bonsai.tool as tool
-
-
-Z_ROTATION_ALIGNMENT_TOLERANCE = 1e-9
-
-
-def _z_rotation_diff(target_z: float, source_z: float) -> float:
-    """Signed Z-Euler difference wrapped to [-π, π]."""
-    return (target_z - source_z + math.pi) % (2 * math.pi) - math.pi
-
-
-def copy_z_rotation_to_selected(
-    ifc: type[tool.Ifc],
-    geometry: type[tool.Geometry],
-    surveyor: type[tool.Surveyor],
-    *,
-    active: bpy.types.Object,
-    targets: Iterable[bpy.types.Object],
-    flip: bool = False,
-) -> int:
-    """Apply ``active``'s Z-Euler rotation to each target."""
-    source_z = surveyor.get_z_rotation(active)
-    if flip:
-        source_z += math.pi
-    rotated = 0
-    for obj in targets:
-        if abs(_z_rotation_diff(surveyor.get_z_rotation(obj), source_z)) < Z_ROTATION_ALIGNMENT_TOLERANCE:
-            continue
-        surveyor.set_z_rotation(obj, source_z)
-        rotated += 1
-        if ifc.get_entity(obj) is not None:
-            bonsai.core.geometry.edit_object_placement(ifc, geometry, surveyor, obj=obj)
-    return rotated

src/bonsai/bonsai/core/tool.py

@@ -195,6 +195,14 @@ class Collector:
     def assign(cls, obj, should_clean_users_collection=False): pass
 
 
+@interface
+class Connection:
+    def find_rel(cls, elem_a, elem_b): pass
+    def find_rels(cls, elem_a, elem_b): pass
+    def find_rels_for_element(cls, elem): pass
+    def orient_element_top(cls, rel, elem_a, elem_b): pass
+
+
 @interface
 class Context:
     def clear_context(cls): pass
@@ -246,7 +254,6 @@ class Cost:
     def get_cost_schedule(cls, cost_schedule): pass
     def get_cost_value_attributes(cls): pass
     def get_cost_value_unit_component(cls): pass
-    def get_direct_cost_item_products(cls): pass
     def get_highlighted_cost_item(cls): pass
     def get_products(cls, related_object_type): pass
     def get_schedule_cost_items(cls, cost_schedule): pass
@@ -347,6 +354,8 @@ class Drawing:
     def enable_editing_schedules(cls): pass
     def enable_editing_sheets(cls): pass
     def enable_editing_text(cls, obj): pass
+    def ensure_drawings_parent_document(cls): pass
+    def ensure_drawings_parent_group(cls): pass
     def ensure_unique_drawing_name(cls, name): pass
     def ensure_unique_identification(cls, identification): pass
     def export_font_size(cls, obj): pass
@@ -694,11 +703,13 @@ class Model:
     def load_openings(cls, openings): pass
     def purge_scene_openings(cls): pass
     def recalculate_walls(cls, objs): pass
+    def recreate_wall(cls, element, obj): pass
     def regenerate_array(cls, parent, data): pass
     def regenerate_profile(cls, obj): pass
     def regenerate_slab(cls, obj): pass
     def reload_body_representation(cls, obj_or_objects): pass
     def remove_wall_to_underside_booleans(cls, wall): pass
+    def strip_underside_booleans(cls, wall): pass
     def replace_object_ifc_representation(cls, ifc_file, ifc_context, obj, new_representation): pass
 
 
@@ -794,7 +805,7 @@ class Profile:
 
 @interface
 class Parametric:
-    def get_geom_generation(cls) -> int: pass
+    def get_geom_generation(cls): pass
     def refresh_post_commit(cls, operator) -> None: pass
 
 
@@ -1160,8 +1171,6 @@ class Style:
 @interface
 class Surveyor:
     def get_absolute_matrix(cls, obj): pass
-    def get_z_rotation(cls, obj): pass
-    def set_z_rotation(cls, obj, z): pass
 
 
 @interface
@@ -1198,6 +1207,7 @@ class Type:
     def get_representation_context(cls, representation): pass
     def get_type_occurrences(cls, element_type): pass
     def has_material_usage(cls, element): pass
+    def is_relating_type_compatible(cls, occurrence, relating_type): pass
     def record_material_usage_attributes(cls, element): pass
     def restore_material_usage_attributes(cls, element, usage_attributes): pass
     def run_geometry_add_representation(cls, obj=None, context=None, ifc_representation_class=None, profile_set_usage=None): pass

src/bonsai/bonsai/tool/__init__.py

@@ -30,7 +30,9 @@ from bonsai.tool.bsdd import Bsdd
 from bonsai.tool.cad import Cad
 from bonsai.tool.clash import Clash
 from bonsai.tool.classification import Classification
+from bonsai.tool.clip_box import ClipBox
 from bonsai.tool.collector import Collector
+from bonsai.tool.connection import Connection
 from bonsai.tool.context import Context
 from bonsai.tool.cost import Cost
 from bonsai.tool.covering import Covering
@@ -78,3 +80,6 @@ from bonsai.tool.type import Type
 from bonsai.tool.unit import Unit
 from bonsai.tool.wall import Wall
 from bonsai.tool.web import Web
+
+# Have to move after import of tool.drawing
+from bonsai.tool.autosave import Autosave  # isort: skip