Add bulk-load of selected drawings' annotations

SHIFT+CTRL+CLICK on Activate Drawing now imports the
annotations of all selected drawings without switching
the active view or camera, then selects their cameras with
the first as active. SHIFT+CTRL+ALT+CLICK also selects the
loaded annotation objects. The drawing camera is imported
when missing so annotations land in the correct collection.
Loading is idempotent.

Generated with the assistance of an AI coding tool.

.gitignore

@@ -127,6 +127,7 @@ 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

@@ -314,8 +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

docs/dev-notes/linked-file-features.md

@@ -1,400 +0,0 @@
-<!-- This file was generated with the assistance of an AI coding tool. -->
-
-# Linked file features — queries, styles, transforms, and multi-linking for linked IFC models
-
-> **Living dev note** for the `Linked_File_Features` branch/PR. Read before working
-> on the feature; append decisions and findings as the PR is refined. This is *not* user
-> documentation — at merge it is removed or its durable parts promoted to code comments.
-> See [README.md](README.md) for the convention (introduced on the
-> `opening-template-on-type` branch; not yet on this branch's base).
-
-## Problem
-
-Linked IFC models (`bim.link_ifc`) had several gaps that made them hard to use as a
-"reference in other trades' models" workflow:
-
-- One shared `.ifc.cache.blend` per IFC file meant the **same file could not be linked
-  twice with different selector queries** — both links showed whichever query was cached
-  first in-session, and whichever was cached last after reopening (Blender reuses one
-  library datablock per path).
-- The selector query was not durably stored anywhere in the host IFC, so save → reopen
-  lost or cross-wired the filter; a scripted `bpy.ops.bim.reload_link()` also wiped it.
-- Linked geometry got **flat diffuse-only materials** — external `.blend` styles
-  (`IfcExternallyDefinedSurfaceStyle`) and per-layer materials (layerset slicing) that
-  the normal import applies were ignored.
-- Moving a linked model required an explicit enable-edit → move → save dance on the
-  active link only, with save/cancel buttons in the panel header.
-- The Explore tool's highlight broke (GPU type errors), drew at the link's *original*
-  location when the link had been moved, and `bim.append_inspected_linked_element`
-  placed appended elements at the original location too.
-
-## Key facts established
-
-- **Cache architecture**: `LoadLink.link_ifc` generates a Python script and runs a
-  background Blender subprocess that executes `bim.load_linked_project` and saves a
-  `.ifc.cache.blend`. The host session then *links* (not appends) the `IfcProject/...`
-  collection from that blend and instances it via an empty (the link "handle").
-  Georeferencing metadata lives in a sidecar `.cache.json`; extracted properties in
-  `.cache.sqlite` (whole file, query-independent — deliberately shared across queries).
-- **Blender reuses an in-session library per path.** Loading the same blend path twice
-  yields the same library/collection. This is what broke multi-query linking with a
-  shared cache filename, and why per-query *filenames* (not cache invalidation) are the
-  fix.
-- **Last-used operator properties** are reused on the next *interactive* invocation
-  (UI button), while scripted `bpy.ops` calls always start from defaults. LoadLink's
-  internal `self.query = link.query` fallback assignment was remembered by Blender and
-  leaked into the next button click (`operator_query='IfcWindow'` for the door link).
-  Any `is_property_set()`-based logic is corrupted the same way. Fix: `SKIP_SAVE` on
-  volatile props. **A GUI-only bug like this is invisible to scripted repro** — both
-  headless and windowed `--python` test runs passed while the manual flow failed.
-- **`IfcDocumentReference`** per link: attribute index 1 (`Identification`) already
-  stores the link's 4×4 transformation (existing Bonsai convention). `Description`
-  (IFC4+; **absent in IFC2X3**) now stores the selector query. One
-  `IfcDocumentInformation` (Scope `LINKED_MODEL`) per file, one reference per link.
-- **Geometry iterator materials**: `material.instance_id()` is the STEP id of the
-  `IfcSurfaceStyle` — or of an `IfcMaterial` when the item has a material but no style,
-  hence the `is_a("IfcSurfaceStyle")` guard when resolving external styles.
-- **External styles**: `IfcExternallyDefinedSurfaceStyle.Location` (`.blend`, relative
-  paths resolve against the *linked* IFC, not the host) + `Identification` in
-  `data_block_type/name` form (e.g. `materials/Brick`), same convention as
-  `bim.activate_external_style`.
-- **Chunk pipeline dedups materials by RGBA color** (`np.unique` on a color array), so
-  style identity must ride along as an extra column to survive — added only for styles
-  that actually resolve to an external material, so plain colored styles dedupe exactly
-  as before.
-- **`slice_layerset_mesh` needs a local-space, per-element mesh** (bisect planes are in
-  object space), which the chunk path can't provide (world-space, many elements per
-  mesh) — hence routing multi-layer elements through the instanced path. Its
-  `dissolve_limit` produces **ngons**, which broke the Explore highlight's
-  triangles-from-`polygon.vertices` assumption downstream.
-- **ID properties round-trip as `IDPropertyArray`**, not plain lists (verified in
-  4.5.7: empty list → flat `IDPropertyArray`; nested lists → list of `IDPropertyArray`
-  items), and `GPUIndexBuf` rejects them — selection geometry must be converted to
-  plain tuples on read.
-- **`scene.ray_cast` returns the hit instance's world matrix** (link empty matrix
-  included). For instanced occurrence objects the object's own local matrix is *not*
-  identity, so resolving the instancing empty must compare against
-  `empty.matrix_world @ obj.matrix_world`, not the empty's matrix alone.
-- **Link matrix math**: the handle empty's matrix is `inv(L) @ T @ G` (L = host local
-  matrix from georef props, T = stored transformation, G = linked model's global
-  matrix from the cache json). The world-space displacement of a moved link is
-  therefore `inv(L) @ T @ L` — no json read needed (`calculate_link_delta_matrix`).
-- **Undo consistency of auto-saved moves**: Blender undo of a handle move fires another
-  depsgraph update, so the handler re-saves the reverted matrix — stored state stays
-  consistent without transactions (a handler can't open one).
-
-## Design
-
-### Per-query caches + query persistence (multi-linking)
-
-`tool.Project.get_link_cache_paths(filepath, query)` appends `.md5(query)[:8]` to the
-cache blend/json names; the empty query keeps the legacy un-suffixed names so existing
-caches stay valid. Every cache-path consumer goes through it — `link_ifc` build and
-invalidation, the subprocess json write, model-origin/georef indicator reads,
-`calculate_link_matrix`, `save_link_transformation`, and the per-link
-selectability/wireframe/visibility toggles (which match collections *by library
-filepath* and would otherwise affect every link of the file at once).
-
-The query persists on each link's `IfcDocumentReference.Description` (written by
-`LinkIfc` and `ReloadLink`); `load_linked_models_from_ifc` restores from it, with a
-legacy-JSON fallback that only applies when the file has a **single** link (with
-several links the shared JSON can't say which link it belonged to). IFC2X3 hosts have
-no `Description` — custom queries are not restorable there (accepted).
-
-`LoadLink`/`ReloadLink` volatile properties are `SKIP_SAVE` (see key facts). Cache
-clearing tolerates a missing blend (a reload with a brand-new query points at a
-not-yet-existing filename).
-
-### Include/Exclude filter pair
-
-The selector grammar's only cross-group combiner is `+` (union) and the `parent`
-facet cannot express "not under X" (its `!=`/regex paths also match by GlobalId, so
-negation removes everything with any parent), which makes set differences like
-"group members minus the slabs under aggregate X" structurally inexpressible in one
-query string. Links therefore carry an **Exclude** query beside the include —
-mirroring `EPset_Drawing`'s Include/Exclude pattern: final set = include (or the
-default set when empty) − exclude, applied in `LoadLinkedProject` and per link in
-`create_drawing`.
-
-- **Cache key**: `get_link_cache_paths` hashes `md5(query + "\0" + exclude)` when an
-  exclude exists; include-only filters keep the pre-exclude `md5(query)` so existing
-  caches stay valid; empty filter keeps legacy un-suffixed names. Keying on query
-  alone would let same-include/different-exclude links silently serve each other's
-  geometry.
-- **Persistence**: `encode_link_filter`/`decode_link_filter` — a plain include is
-  stored in `Description` as-is (backwards compatible); an exclude, a `loaded`
-  state or a custom display name promotes the value to
-  `{"include": …, "exclude": …, "loaded": …, "name": …}` JSON. Decode treats
-  non-JSON as a legacy include string. The display name (`Link.display_name`,
-  double-click the list row to rename; file path shows as placeholder while
-  unset) exists to tell apart several links of the same file.
-- Exclude applies on top of the **default** element set too, so
-  "everything except X" needs no explicit include.
-- UI labels are **Include**/**Exclude** (matching the drawing pattern), but the
-  property identifier stays `query` for script (`bpy.ops.bim.link_ifc(query=…)`)
-  and persistence compatibility.
-- Verified headless: `query=""`/`exclude="IfcDoor"` loads only the window;
-  same file with a different filter gets its own cache; both filters survive
-  save → reopen → reload.
-
-### Auto-load on open
-
-Links that were **loaded and visible** at IFC save time auto-load when the project
-is reopened. `ExportIFC` calls `tool.Project.update_linked_models_state()`, which
-rewrites each reference's `Description` with a `loaded` flag
-(`is_loaded and not is_hidden`); `load_linked_models_from_ifc` replays flagged
-links via `load_link` after restoring the list (missing files warn and skip so
-they can't break project open). The flag extends the same JSON blob as the
-exclude — plain legacy strings decode as no-autoload. Trade-off: project open
-pays the link-load cost up front (fast on cache hit; a missing cache rebuilds in
-a background Blender, same as clicking Load). Verified headless: loaded+visible
-auto-loads; unloaded and loaded-but-hidden links stay unloaded.
-
-### Long-term serialization target: STEP Part 21 Edition 3
-
-STEP p21e3 defines the standards-track version of this feature's persistence:
-`ANCHOR`/`REFERENCE` sections (clauses 9–10) let one file import entities from
-another via URI + fragment, and **anchor tags** (`{tagname: value}`) are the
-designated slot for out-of-schema metadata — a cleaner home than the
-`Description` JSON blob (see the review-round discussion). ifcopenshell does not
-implement these sections yet ([#668](https://github.com/IfcOpenShell/IfcOpenShell/issues/668),
-open, unassigned); if it ever does, the migration path is: link →
-`REFERENCE` to the linked file's project anchor, filter/transform/loaded
-metadata → anchor tags. Keeping the blob behind
-`encode_link_filter`/`decode_link_filter` makes that a two-function change.
-
-Two p21e3 design points this branch already conforms to:
-
-- **Identity**: p21e3 distinguishes volatile file-scoped entity numbers
-  (`#100` fragments) from durable anchors/UUIDs — the same lesson behind our
-  STEP-id collision fixes (GUID-based matching, `element.file` guards). Raw
-  STEP ids must never cross a file boundary; IFC GlobalIds map 1:1 onto
-  p21e3 UUID anchors.
-- **Transport** (clause A.4): exchange structures plus referenced resources
-  can ship as one ZIP archive with references resolving inside it. Our posix,
-  optionally relative `Location`s resolved via `resolve_uri` are exactly the
-  invariants a future "package project with links" export would need.
-
-Even full p21e3 support would not cover per-link transforms, filters, or load
-state — a `REFERENCE` imports entities, it does not place a model — so the
-app-level metadata remains; only its container would change.
-
-### External styles + layerset slicing in the linked loader
-
-`LoadLinkedProject.get_external_material(style_id)` resolves a style id → appended
-Blender material from the external `.blend`, cached two ways (per style id; per
-appended data-block, so styles sharing one material don't append duplicates). Appended
-materials get their stale `ifc_definition_id` cleared (the source `.blend` may have
-been authored in a Bonsai session; the id would be misread in the linked file *and*
-in the host once the cache links in). Applied in both loading paths — instanced
-occurrences directly, chunks via the style-id column.
-
-Multi-layer elements (`IfcMaterialLayerSetUsage`, >1 layer) route through the
-instanced path and get `slice_layerset_mesh`, which gained a pluggable
-`style_to_material` resolver (defaults to the old `tool.Ifc.get_object` for the normal
-import) — the linked resolver prefers the external material, falling back to a flat
-diffuse from the style's shading colour. Also fixed there: newly appended layer
-materials are registered in the dedup dict (two layers sharing one style used to
-append it twice).
-
-Trade-off: layered walls become individual instanced objects instead of chunk members;
-meshes shared between elements (same geometry id) bake the slice from the first
-element's layerset usage — same behaviour as the normal importer.
-
-### Reload Link dialog
-
-`bim.reload_link` now exposes File Path (+ browse button), Use Relative Path
-(defaulting to the stored path form), Use Cache (default off = old always-rebuild
-behaviour), the False Origin Mode project props, and Query. A file browser can't open
-from inside a props dialog, so the browse button runs `bim.select_link_filepath`
-(fileselect) which *reopens* the reload dialog with the chosen path, carrying the
-in-progress dialog state through the round trip (op props are baked at draw time).
-Path changes update `link.name`/`filepath` and, with a host IFC, the reference
-`Location` + document name — which is why `ReloadLink` became a `tool.Ifc.Operator`.
-Script calls without arguments preserve all stored link values via `is_property_set`.
-
-`bim.reload_all_links` (refresh button beside Link IFC in the panel header) reloads
-every *loaded* link via argument-less `reload_link` calls — each link's stored
-path/query/exclude replay and its cache rebuilds from disk. Unloaded links are left
-alone. Deliberately expensive: one background cache rebuild per link.
-
-### Per-row lock toggle + auto-saved transforms
-
-Link editing moved from the panel header into each list row as a lock/unlock icon:
-unlock (`bim.enable_editing_link`) frees the handle; **any movement is persisted
-immediately** by a `depsgraph_update_post` handler (lazy — ticks without transform
-updates cost ~nothing); lock (`bim.disable_editing_link`) saves and locks.
-`bim.edit_link` and the explicit save step are **removed**; cancel/restore semantics
-no longer exist (undo or move it back). The save math lives in
-`tool.Project.save_link_transformation`. Enable/disable take a `link_index`
-(default −1 = active link) so several links can be edited at once and script calls
-stay compatible.
-
-### Explore tool + append fixes for moved links
-
-- Highlight triangles come from `mesh.calc_loop_triangles()` filtered to the queried
-  element's polygon range (ngon-safe); edges keep `polygon.edge_keys` (no diagonals).
-- `get_selected_geometry` converts the ID-prop round trip to plain tuples (GPU
-  rejects `IDPropertyArray`); TRIS drawing gated on its own data.
-- `QueryLinkedElement` passes the ray-cast instance matrix through;
-  `find_obj_root` compares it against `empty @ obj_local` and falls back to the
-  collection's only instance when no matrix is available (select-by-GUID flow).
-- `bim.append_inspected_linked_element` pre-multiplies the imported object's matrix by
-  `calculate_link_delta_matrix(link)`, matching the link by the queried instance's
-  root empty first (filepath alone is ambiguous with several links per file). The
-  element's IFC placement syncs to the moved location on save — intended.
-
-### Drawings (`create_drawing`) — moved links and per-link queries
-
-- The linework serializer opened linked IFCs raw, so a moved link's elements were
-  drawn at their *original* coordinates (usually outside the drawing extents —
-  "linked objects disappear from prints after moving the link").
-- The stored link transformation is already the **model-space** delta (that is how
-  `save_link_transformation` derives it), which is exactly the space the serializer
-  works in — so it can be baked straight into the geometry iterator via the existing
-  `model-offset`/`model-rotation` settings. The mapping composes
-  `Trans(model-offset) @ Rot(model-rotation)` (see `mapping.cpp`), matching the
-  `Trans(t) @ Rot(R)` decomposition of the rigid link matrix; `model-rotation` is a
-  quaternion passed as `(x, y, z, w)`. The pre-existing 2mm plan-view Z-offset simply
-  adds onto the translation (translations commute).
-- The serialization loop previously collected files in a dict keyed by filepath, which
-  **collapsed same-file links into one pass** (one transform — the last link's — and
-  no query awareness): with two links of one file, only one showed in the drawing.
-  It now iterates one entry per link (`(path, file, transform, query)` tuples), and
-  intersects each link's drawing elements with
-  `ifcopenshell.util.selector.filter_elements(ifc, link.query)` so the drawing shows
-  what that link actually displays in the viewport.
-- `tool.Project.get_link_transformation_matrix(link)` is the shared accessor for the
-  stored 4×4 (None when identity/absent).
-- Verified headless with the window/door kit: moved window offset in the SVG by
-  exactly 5m × scale; unmoved door at its native position; both links present.
-
-### Drawings — `.cut` styling for linked models (BISECT cut mode)
-
-- The default **BISECT** cut mode deletes the OpenCASCADE serializer's cut linework
-  (`remove_cut_linework`) and regenerates cuts by bisecting **Blender mesh objects**
-  (`generate_bisect_linework` over `context.visible_objects`). Linked models are
-  instanced collections with no mesh objects, so their cuts were deleted and never
-  regenerated — linked elements only ever appeared as `projection`, and the `.cut`
-  CSS rule never applied to them. Long-standing gap, unrelated to moved links
-  (A/B-tested against pre-branch code: identical).
-- Fix: `remove_cut_linework` only removes cut groups whose guid resolves in the
-  **host** file — linked elements keep the serializer's cut geometry, which the
-  merge step then classes as `cut`.
-- **Cross-file STEP-id collision**: `tool.Ifc.get_object(linked_entity)` resolves the
-  entity's STEP id against the *host* session's id map and can return an arbitrary
-  host object (in the test project: the drawing camera, crashing
-  `generate_material_layers` with "expected 'Mesh' found 'Camera'"). Guarded via
-  `element.file is tool.Ifc.get()` in `generate_material_layers` and the merge step.
-- **Paint order**: the projection-under-cut convention was enforced only in
-  OPENCASCADE mode (`move_projection_to_bottom`); BISECT appends its own cut paths
-  last so it never needed it — but the retained serializer cuts of linked models are
-  emitted *before* the projections. BISECT now runs the same pass; `BringToFront`
-  (`move_elements_to_top`) still gets the final say.
-- Known limitation: linked cut paths are raw serializer output — they skip the
-  shapely path-closing/merging and the material-layer hatching pass (both need host
-  Blender objects). Stroke + fill from `.cut` CSS apply; layered hatching inside
-  linked cuts is a candidate follow-up.
-- Debugging note: merged cut groups carry member guids as CSS *classes*, not as the
-  `ifcopenshell:guid` attribute — inspect both when checking cut output.
-
-## Deferred refactors (deliberate)
-
-- **Upstream `exclude=` on `filter_elements`** — the include−exclude set difference
-  is hand-rolled twice (links, drawings) because the selector grammar has no
-  difference operator and `parent` negation is broken by design (its `!=`/regex
-  paths also match GlobalIds, so negation strips everything that has a parent).
-  The right home is an `exclude=` parameter on
-  `ifcopenshell.util.selector.filter_elements`, documented in
-  `selector_syntax.rst` together with the `parent`-negation limitation. Deferred
-  to a separate ifcopenshell-python PR (different review audience; would widen
-  this PR mid-review). Once it lands, both Bonsai call sites collapse.
-- **Core/tool ceremony skipped** — the new `tool.Project` methods have no
-  `core/tool.py` interface declarations and no `bonsai/core` orchestration
-  functions, matching the pre-existing linked-model code (which bypasses the
-  core layer wholesale; `LoadLinkedProject` is flagged "prototyping" upstream).
-  Interfaces nobody calls through wouldn't add testability — the pure helpers
-  (`encode_link_filter`/`decode_link_filter`, `get_link_cache_paths`) are
-  covered directly in `test/tool/test_project.py` instead. Revisit if the
-  linked-model subsystem is ever promoted out of prototype status.
-
-## Review round 1 (PR #8242, falken10vdl) — decisions
-
-- **Path-form mismatch → duplicate documents (confirmed bug, fixed).**
-  `get_linked_models_documents()` keyed documents by the *stored* `Location`, so
-  linking the same file first relative then absolute (or vice versa) created a second
-  `IfcDocumentInformation`. Both sides of the lookup now normalize through
-  `tool.Ifc.resolve_uri()` before matching.
-- **`Description` for the query — kept.** It is implementation metadata in an IFC
-  attribute, but consistent with the existing convention on these same references
-  (`Identification` stores the 4×4 transformation, a bigger stretch). References are
-  Bonsai-managed (`Scope="LINKED_MODEL"`), so user-description collisions are unlikely.
-  A cleaner consolidated convention (query + transform + options in one serialized
-  attribute) is a candidate follow-up, deliberately out of scope here.
-- **`md5(query)[:8]` — kept.** 32 bits ≈ birthday collision at ~65k distinct queries
-  *per file*; and a collision is not silent: the cache JSON stores the full query and
-  `should_clear_cache()` compares it, so a colliding cache is detected and rebuilt
-  (self-healing).
-- **Depsgraph autosave vs save-on-lock — autosave kept.** Save-on-lock alone loses the
-  "what you see is what's saved" guarantee (move + save project without locking =
-  silently dropped move) and loses undo tracking (undo fires a depsgraph update that
-  re-saves the reverted transform). The handler early-outs when no links exist and only
-  works on ticks containing an object-transform update while a link is unlocked.
-
-## Status — implemented (verified in Blender, incl. headless + GUI repro runs)
-
-Six commits on `Linked_File_Features`:
-
-- `0096c0f6a2` reload_link without a query preserves the stored one.
-- `40db55e52d` external styles + layerset slicing for linked models
-  (`project/operator.py`, `tool/loader.py`).
-- `d210d4c814` full Reload Link dialog + `bim.select_link_filepath`.
-- `3dc161f0f2` per-row lock toggle, auto-save handler, `edit_link` removed
-  (`project/operator.py`, `project/ui.py`, `project/__init__.py`, `tool/project.py`).
-- `0571d22855` Explore highlight (ngons, IDPropertyArray), moved-link highlight,
-  append placement (`tool/project.py`, `project/operator.py`, `project/decorator.py`).
-- `c14592ec0a` per-query caches, Description persistence, SKIP_SAVE.
-
-Plus:
-
-- `ee43ed5526` review-round path normalization in `get_linked_models_documents` /
-  `LinkIfc` (see Review round 1).
-- `1669cbcd43` drawing support for moved links and per-link queries in
-  `create_drawing` (`drawing/operator.py`, `tool/project.py`).
-- `.cut` styling for linked models in BISECT cut mode + STEP-id collision guards +
-  paint order (`drawing/operator.py`) — committed together with this note update.
-
-End-to-end verified with a two-links-one-file kit (window/door, distinct queries):
-correct visuals on load, after save → reopen → reload, in both headless and windowed
-Blender.
-
-## Things to test / verify
-
-- **IFC2X3 host**: `Description` doesn't exist — link queries silently not restored on
-  reopen (legacy fallback only for single-link files). Acceptable? Warn?
-- **Relative-path links** (`use_relative_path`) through the whole cycle: cache paths,
-  reference `Location`, reload path change, query restore. The duplicate-document case
-  (same file linked relative then absolute) is fixed — verify one document with two
-  references via `IfcDocumentInformation.HasDocumentReferences`.
-- Same file linked twice, **both moved differently**: Explore highlight and append
-  placement per instance (root-empty matching), per-link visibility toggles.
-- External styles with **image textures**: paths relative to the style's source
-  `.blend` may not resolve from the cache blend's location (shared limitation with the
-  normal import path).
-- Stale cache orphans: per-query filenames accumulate one blend+json pair per distinct
-  query next to the IFC; nothing auto-deletes them. Cleanup on unlink? Document?
-- Mid-drag auto-save writes the IFC reference outside Bonsai's transaction system —
-  confirm no undo-stack weirdness in longer editing sessions.
-- Layerset slicing on meshes shared by elements with *different* usages (offset/sense)
-  bakes the first element's slice — same as normal import, but worth a look with types.
-- `bim.select_link_filepath` round trip when the reload dialog was opened for a
-  non-active link, and dialog-state carry-over after editing the query *then* browsing.
-- **Drawing SVG guid cache vs moved links**: `create_drawing` skips elements whose
-  guids already exist in the drawing's SVG (`cached_linework`, invalidated only for
-  *edited host objects*). Moving a link does not invalidate its elements, so a
-  regenerated drawing keeps their old positions until the SVG is deleted. Candidate
-  fix: subtract a moved link's guids from `cached_linework` (compare stored transform
-  against the one recorded at last generation).
-- Same element appearing in two links of one file (overlapping queries) serializes
-  twice with different transforms; the SVG guid cache keeps whichever came first on
-  regeneration. Degenerate case — probably fine to ignore, but note it.

src/bonsai/bonsai/bim/handler.py

@@ -320,9 +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

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
@@ -2035,7 +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(),
@@ -2044,7 +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:

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

@@ -602,7 +602,7 @@ class CreateDrawing(bpy.types.Operator):
         context_type: Literal["body", "annotation"],
         drawing_elements: set[ifcopenshell.entity_instance],
         target_view: str,
-        link_transform: Optional[np.ndarray] = None,
+        link_matrix: Optional[Matrix] = None,
     ) -> None:
         drawing_elements = drawing_elements.copy()
         contexts_: list[list[int]] = getattr(contexts, context_type)
@@ -614,22 +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)
 
-                offset = np.zeros(3)
-                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
-                    offset[2] = 0.002 if target_view == "PLAN_VIEW" else -0.002
-                if link_transform is not None:
-                    # Bake a moved link's transformation into the geometry. The
-                    # mapping composes Trans(model-offset) @ Rot(model-rotation),
-                    # matching the Trans(t) @ Rot(R) decomposition of the rigid
-                    # link matrix, so the Z offset above simply adds on.
-                    offset += link_transform[:3, 3]
-                    quaternion = Matrix(link_transform.tolist()).to_quaternion()
-                    geom_settings.set(
-                        "model-rotation", (quaternion.x, quaternion.y, quaternion.z, quaternion.w)
-                    )
-                if offset.any():
-                    geom_settings.set("model-offset", tuple(float(o) for o in offset))
+                    geom_settings.set("model-offset", (0.0, 0.0, z_offset))
 
                 geom_settings.set("context-ids", context)
                 it = ifcopenshell.geom.iterator(
@@ -682,10 +679,6 @@ class CreateDrawing(bpy.types.Operator):
             if "projection" in el.get("class", "").split():
                 continue
             element = self.get_element_by_guid(el.get("{http://www.ifcopenshell.org/ns}guid"))
-            if element is None or element.file is not tool.Ifc.get():
-                # Linked model element - no Blender object to bisect, and its
-                # STEP id must not be resolved against the host session.
-                continue
             if not (obj := tool.Ifc.get_object(element)):
                 continue
             if not (material := ifcopenshell.util.element.get_material(element)):
@@ -941,25 +934,16 @@ class CreateDrawing(bpy.types.Operator):
 
         bim_props = tool.Blender.get_bim_props()
         prefs = tool.Blender.get_addon_preferences()
+        # 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()
-        # One entry per file *and* per link - the same file can be linked
-        # several times with different queries and transformations, so links
-        # cannot be collapsed into a dict keyed by filepath.
-        # Each entry is (path, file, link transformation or None, link query, link exclude).
-        file_entries: list[tuple[str, ifcopenshell.file, Optional[np.ndarray], str, str]] = [
-            (bim_props.ifc_file, tool.Ifc.get(), None, "", "")
-        ]
         for link in props.get_loaded_links_for_drawings():
-            file_entries.append(
-                (
-                    link.filepath,
-                    self.get_linked_file(link),
-                    tool.Project.get_link_transformation_matrix(link),
-                    link.query,
-                    link.exclude,
-                )
-            )
+            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)
@@ -973,7 +957,7 @@ class CreateDrawing(bpy.types.Operator):
         raycast_objs = set()
         elements_with_faces = set()
 
-        for ifc_path, ifc, link_transform, link_query, link_exclude in file_entries:
+        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()
@@ -981,11 +965,6 @@ class CreateDrawing(bpy.types.Operator):
 
             self.serialiser.setFile(ifc)
             drawing_elements = tool.Drawing.get_drawing_elements(self.camera_element, ifc_file=ifc)
-            if link_query:
-                # Draw only what the link's selector filter loaded in the viewport.
-                drawing_elements &= ifcopenshell.util.selector.filter_elements(ifc, link_query)
-            if link_exclude:
-                drawing_elements -= ifcopenshell.util.selector.filter_elements(ifc, link_exclude)
 
             if self.cprops.fill_mode == "SHAPELY":
                 for element in drawing_elements.copy():
@@ -1001,11 +980,9 @@ class CreateDrawing(bpy.types.Operator):
             # 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, link_matrix)
             self.serialize_contexts_elements(
-                ifc, tree, contexts, "body", drawing_elements, target_view, link_transform
-            )
-            self.serialize_contexts_elements(
-                ifc, tree, contexts, "annotation", drawing_elements, target_view, link_transform
+                ifc, tree, contexts, "annotation", drawing_elements, target_view, link_matrix
             )
 
             if tool.Ifc.get() == ifc and self.camera_element not in drawing_elements:
@@ -1061,10 +1038,6 @@ class CreateDrawing(bpy.types.Operator):
             if self.cprops.generate_material_layers:
                 self.generate_material_layers(context, root)
             self.merge_linework_and_add_metadata(root)
-            # Bisect cut linework is appended after the projections, but the
-            # retained serializer cuts of linked models precede them - enforce
-            # the projection-under-cut convention like OPENCASCADE mode does.
-            self.move_projection_to_bottom(root)
             self.move_elements_to_top(root)
         elif self.cprops.cut_mode == "OPENCASCADE":
             self.move_projection_to_bottom(root)
@@ -1460,21 +1433,9 @@ class CreateDrawing(bpy.types.Operator):
                     continue
 
     def remove_cut_linework(self, root):
-        """Remove host elements' cut linework so bisecting can regenerate it.
-
-        Linked model elements keep the serializer's cut geometry - bisect
-        linework is generated from Blender mesh objects, and linked models
-        are instanced collections without any.
-        """
-        ifc_file = tool.Ifc.get()
         for el in root.findall(".//{http://www.w3.org/2000/svg}g[@{http://www.ifcopenshell.org/ns}guid]"):
-            if "projection" in el.get("class", "").split():
-                continue
-            try:
-                ifc_file.by_guid(el.get("{http://www.ifcopenshell.org/ns}guid"))
-            except RuntimeError:
-                continue  # Linked model element.
-            el.getparent().remove(el)
+            if "projection" not in el.get("class", "").split():
+                el.getparent().remove(el)
 
     def merge_linework_and_add_metadata(self, root):
         join_criteria = ifcopenshell.util.element.get_pset(self.camera_element, "EPset_Drawing", "JoinCriteria")
@@ -1509,9 +1470,7 @@ class CreateDrawing(bpy.types.Operator):
                 classes.append("cut")
                 el.set("class", " ".join(classes))
 
-            # Resolving a linked element's STEP id against the host session
-            # would return an arbitrary host object.
-            obj = tool.Ifc.get_object(element) if element is not None and element.file is tool.Ifc.get() else None
+            obj = tool.Ifc.get_object(element)
 
             if not obj:  # This is a linked model object. For now, do nothing.
                 continue
@@ -2384,7 +2343,9 @@ class ActivateDrawingBase(tool.Ifc.Operator):
         "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.\n\n"
-        + "SHIFT+CTRL+CLICK to load the annotations of all selected drawings without switching views"
+        + "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()
@@ -2406,16 +2367,25 @@ class ActivateDrawingBase(tool.Ifc.Operator):
         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
@@ -2430,15 +2400,34 @@ class ActivateDrawingBase(tool.Ifc.Operator):
             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 tool.Ifc.get_object(selected_drawing):
-                    tool.Drawing.import_drawing(selected_drawing)
-                tool.Drawing.import_annotations_in_group(tool.Drawing.get_drawing_group(selected_drawing))
+                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)
@@ -2527,7 +2516,9 @@ class ActivateDrawing(bpy.types.Operator, ActivateDrawingBase):
         "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.\n\n"
-        + "SHIFT+CTRL+CLICK to load the annotations of all selected drawings without switching views"
+        + "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"
     )
 
 

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

@@ -27,6 +27,7 @@ import bonsai.tool as tool
 from . import (
     array,
     covering,
+    decorator,
     door,
     external,
     grid,

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

@@ -38,6 +38,7 @@ import numpy as np
 from ifcopenshell.util.shape_builder import ShapeBuilder
 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

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

@@ -138,7 +138,7 @@ def update_bbim_railing_pset(element: ifcopenshell.entity_instance, railing_data
 
 def generate_wall_mounted_handrail_preview(
     obj: bpy.types.Object,
-    props: "BIMRailingProperties",
+    props: "prop.BIMRailingProperties",
     path_data: dict[str, Any],
     si_conversion: float,
 ) -> None:
@@ -860,7 +860,9 @@ class GizmoRailingSchematic(bpy.types.GizmoGroup, gizmo.BaseSchematicGizmoGroup)
         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: "BIMRailingProperties") -> None:
+    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,

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 = (
@@ -45,6 +47,7 @@ classes = (
     operator.DisableEditingHeader,
     operator.DisableEditingLink,
     operator.EditHeader,
+    operator.EditLink,
     operator.EditProjectLibrary,
     operator.EnableCulling,
     operator.EnableEditingHeader,
@@ -57,6 +60,8 @@ classes = (
     operator.LinkIfc,
     operator.LoadBlendMetadataAndIFC,
     operator.LoadLink,
+    operator.AutosavePrompt,
+    operator.LoadAutosavedRecoveryPopup,
     operator.LoadLinkedProject,
     operator.LoadProject,
     operator.LoadProjectElements,
@@ -66,7 +71,6 @@ classes = (
     operator.QueryLinkedElement,
     operator.RefreshClippingPlanes,
     operator.RefreshLibrary,
-    operator.ReloadAllLinks,
     operator.ReloadLink,
     operator.RemoveProjectLibrary,
     operator.RevertProject,
@@ -74,7 +78,6 @@ classes = (
     operator.SaveLibraryFile,
     operator.SelectLibraryFile,
     operator.SelectLinkedModelElement,
-    operator.SelectLinkFilepath,
     operator.SelectLinkHandle,
     operator.ToggleFilterCategories,
     operator.ToggleLinkSelectability,
@@ -110,45 +113,12 @@ classes = (
 addon_keymaps = []
 
 
-@bpy.app.handlers.persistent
-def _autosave_link_transforms(scene, depsgraph):
-    """Persist link transformations whenever an editing link's handle is moved.
-
-    Deliberate exemption from the transaction rule in
-    docs/guides/development/undo_system.rst: a handler cannot run inside
-    execute_ifc_operator, so this IFC write is not undo-tracked. It stays
-    consistent anyway because undoing the move fires another depsgraph
-    update, which re-saves the reverted matrix.
-    """
-    import bonsai.tool as tool
-
-    props = tool.Project.get_project_props()
-    if not props.links:
-        return
-    handles = None
-    for update in depsgraph.updates:
-        if not update.is_updated_transform or not isinstance(update.id, bpy.types.Object):
-            continue
-        if handles is None:
-            # Built lazily so ticks without transform updates stay cheap.
-            handles = {}
-            for link in props.links:
-                if link.is_loaded and link.is_editing and (handle := tool.Project.get_link_empty_handle(link)):
-                    handles[handle] = link
-            if not handles:
-                return
-        if link := handles.get(update.id.original):
-            tool.Project.save_link_transformation(link)
-
-
 def register():
     if not bpy.app.background:
         bpy.utils.register_tool(workspace.ExploreTool, after={"builtin.transform"}, separator=True, group=False)
     bpy.types.Scene.BIMProjectProperties = bpy.props.PointerProperty(type=prop.BIMProjectProperties)
     bpy.types.Scene.MeasureToolSettings = bpy.props.PointerProperty(type=prop.MeasureToolSettings)
     bpy.app.handlers.load_post.append(decorator.toggle_decorations_on_load)
-    if _autosave_link_transforms not in bpy.app.handlers.depsgraph_update_post:
-        bpy.app.handlers.depsgraph_update_post.append(_autosave_link_transforms)
     bpy.types.TOPBAR_MT_file_import.append(ui.file_import_menu)
     bpy.types.TOPBAR_MT_file.prepend(ui.file_menu)
     bpy.types.TOPBAR_MT_file_context_menu.prepend(ui.file_menu)
@@ -170,11 +140,10 @@ 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)
-    if _autosave_link_transforms in bpy.app.handlers.depsgraph_update_post:
-        bpy.app.handlers.depsgraph_update_post.remove(_autosave_link_transforms)
     bpy.types.TOPBAR_MT_file.remove(ui.file_menu)
     bpy.types.TOPBAR_MT_file_context_menu.remove(ui.file_menu)
 

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

@@ -99,7 +99,6 @@ class ProjectDecorator:
 
         if geom.selected_edges:
             self.draw_batch("LINES", selected_vertices, selected_elements_color, geom.selected_edges)
-        if geom.selected_tris:
             self.draw_batch(
                 "TRIS", selected_vertices, tool.Blender.transparent_color(selected_elements_color), geom.selected_tris
             )

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

@@ -985,8 +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
@@ -995,6 +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
@@ -1041,7 +1044,26 @@ class LoadProject(bpy.types.Operator, IFCFileSelector, ImportHelper):
 
         return tooltip
 
+    def check_autosave_recovery(self, context: bpy.types.Context) -> set["rna_enums.OperatorReturnItems"] | None:
+        if self.skip_autosave_recovery:
+            return None
+        autosaved_filepath = tool.Autosave.get_newer_autosaved_path(self.get_filepath_abs())
+        if not autosaved_filepath:
+            return None
+        return 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,
+        )
+
     def execute(self, context):
+        if recovery := self.check_autosave_recovery(context):
+            return recovery
+
         if (
             tool.Blender.get_addon_preferences().save_metadata_blend_file
             and self.should_start_fresh_session
@@ -1136,7 +1158,8 @@ 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
@@ -1149,10 +1172,13 @@ 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 recovery := self.check_autosave_recovery(context):
+                return recovery
             return self.execute(context)
         return ImportHelper.invoke(self, context, event)
 
@@ -1360,18 +1386,10 @@ class LinkIfc(bpy.types.Operator, ImportHelper, tool.Ifc.Operator):
     )
     use_cache: bpy.props.BoolProperty(name="Use Cache", default=True)
     query: bpy.props.StringProperty(
-        name="Include",
+        name="Query",
         description=(
-            "Selector query for the elements to load from the linked model. E.g. 'IfcElement'.\n\n"
-            "Default when empty - IfcElement, but excluding IfcProxy, IfcSpatialStructureElement, IfcSpatialElement, IfcFeatureElement."
-        ),
-    )
-    exclude: bpy.props.StringProperty(
-        name="Exclude",
-        description=(
-            "Selector query whose matches are excluded from the loaded elements.\n\n"
-            "Applied on top of the query (or the default set), providing the set "
-            "difference a single query cannot express. E.g. 'IfcSlab, parent=\"X\"'."
+            "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."
         ),
     )
 
@@ -1385,7 +1403,6 @@ class LinkIfc(bpy.types.Operator, ImportHelper, tool.Ifc.Operator):
         use_relative_path: bool
         use_cache: bool
         query: str
-        exclude: str
 
     def draw(self, context):
         assert self.layout
@@ -1404,7 +1421,6 @@ class LinkIfc(bpy.types.Operator, ImportHelper, tool.Ifc.Operator):
             row = self.layout.row()
             row.prop(pprops, "project_north")
         self.layout.prop(self, "query", placeholder="IfcElement")
-        self.layout.prop(self, "exclude", placeholder='IfcSlab, parent="..."')
 
     def _execute(self, context):
         start = time.time()
@@ -1427,26 +1443,18 @@ class LinkIfc(bpy.types.Operator, ImportHelper, tool.Ifc.Operator):
 
             new = props.links.add()
             if tool.Ifc.get():
-                # Look up by resolved absolute path so a file already linked
-                # with a relative Location (or vice versa) reuses its document.
-                resolved_filepath = Path(tool.Ifc.resolve_uri(filepath)).as_posix()
-                if not (document := existing_links.get(resolved_filepath)):
+                if not (document := existing_links.get(filepath)):
                     document = ifcopenshell.api.document.add_information(tool.Ifc.get())
                     document.Name = Path(filepath).name
                     document.Scope = "LINKED_MODEL"
                 reference = ifcopenshell.api.document.add_reference(tool.Ifc.get(), information=document)
                 reference[1] = ",".join([str(o) for o in np.eye(4).flatten().tolist()])
                 reference.Location = filepath.replace("\\", "/")
-                # Persist the filter per reference (Description is IFC4+ only).
-                description = tool.Project.encode_link_filter(self.query, self.exclude, loaded=True)
-                if description and hasattr(reference, "Description"):
-                    reference.Description = description
                 new.ifc_definition_id = reference.id()
             new.name = filepath
             new.filepath = filepath
             new.query = self.query
-            new.exclude = self.exclude
-            bpy.ops.bim.load_link(link_index=-1, use_cache=self.use_cache, query=self.query, exclude=self.exclude)
+            bpy.ops.bim.load_link(link_index=-1, use_cache=self.use_cache, query=self.query)
 
 
 class UnlinkIfc(bpy.types.Operator, tool.Ifc.Operator):
@@ -1505,28 +1513,21 @@ class LoadLink(bpy.types.Operator, tool.Ifc.Operator):
     bl_options = {"REGISTER", "UNDO"}
     bl_description = "Load the selected file"
 
-    # SKIP_SAVE: Blender reuses an operator's last-used property values on the
-    # next interactive invocation, which would leak one link's query/cache
-    # settings into another link's load.
     link_index: bpy.props.IntProperty(name="Link Index")
-    use_cache: bpy.props.BoolProperty(name="Use Cache", default=True, options={"SKIP_SAVE"})
-    query: bpy.props.StringProperty(options={"SKIP_SAVE"})
-    exclude: bpy.props.StringProperty(options={"SKIP_SAVE"})
+    use_cache: bpy.props.BoolProperty(name="Use Cache", default=True)
+    query: bpy.props.StringProperty()
 
     if TYPE_CHECKING:
         link_index: int
         use_cache: bool
         query: str
-        exclude: str
 
     def _execute(self, context):
         self.link = tool.Project.get_project_props().links[self.link_index]
-        # Fall back to the Link's stored filter so callers that omit it
+        # 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
-        if not self.exclude and self.link.exclude:
-            self.exclude = self.link.exclude
         filepath = Path(tool.Ifc.resolve_uri(self.link.filepath))
         if not filepath.exists():
             self.report({"ERROR"}, f"File does not exist: '{filepath}'")
@@ -1563,21 +1564,22 @@ class LoadLink(bpy.types.Operator, tool.Ifc.Operator):
             self.link.is_loaded = False
 
     def link_ifc(self) -> Union[set[str], None]:
-        blend_filepath, json_filepath = tool.Project.get_link_cache_paths(self.filepath_, self.query, self.exclude)
+        blend_filepath = self.filepath_.with_suffix(".ifc.cache.blend")
+        h5_filepath = self.filepath_.with_suffix(".ifc.cache.h5")
+        json_filepath = self.filepath_.with_suffix(".ifc.cache.json")
 
         def should_clear_cache() -> bool:
             if not self.use_cache:
                 return True
             if not blend_filepath.exists():
                 return False
-            if not json_filepath.exists():
-                return True
             data = json.loads(json_filepath.read_text())
             # Empty 'query' - model loaded without custom query.
             # Missing 'query' - model was loaded before custom queries were introduced in Bonsai.
-            return data.get("query", "") != self.query or data.get("exclude", "") != self.exclude
+            query = data.get("query", "")
+            return query != self.query
 
-        if should_clear_cache() and blend_filepath.exists():
+        if should_clear_cache():
             os.remove(blend_filepath)
 
         if not blend_filepath.exists():
@@ -1605,7 +1607,7 @@ def run():
     pprops.project_north = "{pprops.project_north}"
     # Use absolute path to be safe from cwd changes.
     try:
-        bpy.ops.bim.load_linked_project(filepath=r"{str(self.filepath_)}", query={repr(self.query)}, exclude={repr(self.exclude)})
+        bpy.ops.bim.load_linked_project(filepath=r"{str(self.filepath_)}", query={repr(self.query)})
     except RuntimeError as e:
         # Operator failed (returned CANCELLED with error report)
         print(f"Failed to load linked project: {{e}}")
@@ -1654,7 +1656,7 @@ except Exception as e:
         if len(tool.Project.get_project_props().links) > 1:
             return  # Only the first link sets the origin
 
-        json_filepath = tool.Project.get_link_cache_paths(self.filepath_, self.query, self.exclude)[1]
+        json_filepath = self.filepath_.with_suffix(".ifc.cache.json")
         if not json_filepath.exists():
             return
 
@@ -1673,7 +1675,8 @@ except Exception as e:
         if not (crs_name := (ifcopenshell.util.geolocation.get_crs(tool.Ifc.get()) or {}).get("Name", "")):
             self.link.georeferenced = "NONE"
             return
-        json_filepath = tool.Project.get_link_cache_paths(self.filepath_, self.query, self.exclude)[1]
+        reference = tool.Ifc.get().by_id(self.link.ifc_definition_id)
+        json_filepath = Path(reference.Location).with_suffix(".ifc.cache.json")
         if not json_filepath.exists():
             self.link.georeferenced = "NONE"
             return
@@ -1685,211 +1688,43 @@ except Exception as e:
             self.link.georeferenced = "FULL_COMPATIBLE" if crs_name == data["model_crs"] else "NOT_COMPATIBLE"
 
 
-class ReloadLink(bpy.types.Operator, tool.Ifc.Operator):
+class ReloadLink(bpy.types.Operator):
     bl_idname = "bim.reload_link"
     bl_label = "Reload Link"
     bl_options = {"REGISTER", "UNDO"}
-    bl_description = "Reload the selected file, optionally changing its file path and load options"
+    bl_description = "Reload the selected file"
 
-    # SKIP_SAVE: this operator distinguishes "provided" from "unset" properties
-    # via is_property_set, so last-used property retention between interactive
-    # invocations would leak one link's settings into another's reload.
     link_index: bpy.props.IntProperty(name="Link Index")
-    filepath: bpy.props.StringProperty(
-        name="File Path",
-        description="Path to the linked IFC file",
-        options={"SKIP_SAVE"},
-    )
-    use_relative_path: bpy.props.BoolProperty(
-        name="Use Relative Path",
-        description="Whether to store linked model path relative to the currently opened IFC file.",
-        default=False,
-        options={"SKIP_SAVE"},
-    )
-    use_cache: bpy.props.BoolProperty(
-        name="Use Cache",
-        description="Reuse the cached geometry if it's still valid instead of reprocessing the IFC",
-        default=False,
-        options={"SKIP_SAVE"},
-    )
     query: bpy.props.StringProperty(
-        name="Include",
+        name="Query",
         description=(
-            "Selector query for the elements to load from the linked model. E.g. 'IfcElement'.\n\n"
-            "Default when empty - IfcElement, but excluding IfcProxy, IfcSpatialStructureElement, IfcSpatialElement, IfcFeatureElement."
+            "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."
         ),
-        options={"SKIP_SAVE"},
-    )
-    exclude: bpy.props.StringProperty(
-        name="Exclude",
-        description=(
-            "Selector query whose matches are excluded from the loaded elements.\n\n"
-            "Applied on top of the query (or the default set), providing the set "
-            "difference a single query cannot express. E.g. 'IfcSlab, parent=\"X\"'."
-        ),
-        options={"SKIP_SAVE"},
     )
 
     if TYPE_CHECKING:
         link_index: int
-        filepath: str
-        use_relative_path: bool
-        use_cache: bool
         query: str
-        exclude: str
 
     def invoke(self, context, event):
         link = tool.Project.get_project_props().links[self.link_index]
-        # Properties may arrive pre-set when the dialog is reopened
-        # by bim.select_link_filepath - don't clobber them.
-        if not self.properties.is_property_set("filepath"):
-            self.filepath = link.filepath
-        if not self.properties.is_property_set("use_relative_path"):
-            self.use_relative_path = not Path(link.filepath).is_absolute()
-        if not self.properties.is_property_set("query"):
-            self.query = link.query
-        if not self.properties.is_property_set("exclude"):
-            self.exclude = link.exclude
+        self.query = link.query
         return context.window_manager.invoke_props_dialog(self)
 
     def draw(self, context):
         assert self.layout
-        pprops = tool.Project.get_project_props()
-        row = self.layout.row(align=True)
-        row.prop(self, "filepath")
-        op = row.operator("bim.select_link_filepath", text="", icon="FILEBROWSER")
-        op.link_index = self.link_index
-        # Carry the current dialog state through the file browser round-trip.
-        op.use_relative_path = self.use_relative_path
-        op.use_cache = self.use_cache
-        op.query = self.query
-        op.exclude = self.exclude
-        row = self.layout.row()
-        row.prop(self, "use_relative_path")
-        row = self.layout.row()
-        row.prop(self, "use_cache")
-        row = self.layout.row()
-        row.label(text="False Origin Mode:")
-        row = self.layout.row()
-        row.prop(pprops, "false_origin_mode", text="")
-        if pprops.false_origin_mode == "MANUAL":
-            row = self.layout.row()
-            row.prop(pprops, "false_origin")
-            row = self.layout.row()
-            row.prop(pprops, "project_north")
         self.layout.prop(self, "query", placeholder="IfcElement")
-        self.layout.prop(self, "exclude", placeholder='IfcSlab, parent="..."')
 
-    def _execute(self, context):
+    def execute(self, context):
         link = tool.Project.get_project_props().links[self.link_index]
-        # Unset properties mean the operator was called without the dialog
-        # (e.g. from a script) - preserve the link's stored values instead
-        # of overwriting them with the defaults.
+        # 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
-        if self.properties.is_property_set("exclude"):
-            link.exclude = self.exclude
-
-        filepath = self.filepath if self.properties.is_property_set("filepath") else link.filepath
-        if self.properties.is_property_set("use_relative_path"):
-            use_relative_path = self.use_relative_path
-        else:
-            use_relative_path = not Path(link.filepath).is_absolute()
-
-        abs_filepath = Path(tool.Ifc.resolve_uri(filepath))
-        if not abs_filepath.exists():
-            self.report({"ERROR"}, f"File does not exist: '{abs_filepath}'")
-            return {"CANCELLED"}
-        filepath = tool.Ifc.get_uri(abs_filepath, use_relative_path=use_relative_path)
-        if filepath != link.filepath:
-            link.name = filepath
-            link.filepath = filepath
-            if tool.Ifc.get() and link.ifc_definition_id:
-                reference = tool.Ifc.get().by_id(link.ifc_definition_id)
-                reference.Location = filepath.replace("\\", "/")
-                if document := tool.Document.get_reference_document(reference):
-                    document.Name = Path(filepath).name
-        if tool.Ifc.get() and link.ifc_definition_id:
-            reference = tool.Ifc.get().by_id(link.ifc_definition_id)
-            if hasattr(reference, "Description"):
-                reference.Description = tool.Project.encode_link_filter(
-                    link.query, link.exclude, loaded=True, display_name=link.display_name
-                )
-
         bpy.ops.bim.unload_link(link_index=self.link_index)
-        return bpy.ops.bim.load_link(
-            link_index=self.link_index, use_cache=self.use_cache, query=link.query, exclude=link.exclude
-        ) or {"FINISHED"}
-
-
-class ReloadAllLinks(bpy.types.Operator):
-    bl_idname = "bim.reload_all_links"
-    bl_label = "Reload All Links"
-    bl_options = {"REGISTER", "UNDO"}
-    bl_description = "Reload all loaded linked models from disk, rebuilding their caches"
-
-    @classmethod
-    def poll(cls, context):
-        if not any(link.is_loaded for link in tool.Project.get_project_props().links):
-            cls.poll_message_set("No loaded links to reload.")
-            return False
-        return True
-
-    def execute(self, context):
-        props = tool.Project.get_project_props()
-        reloaded = 0
-        for i, link in enumerate(props.links):
-            if not link.is_loaded:
-                continue
-            # Called without filter properties, reload_link preserves each
-            # link's stored path, query and exclude.
-            bpy.ops.bim.reload_link(link_index=i)
-            reloaded += 1
-        self.report({"INFO"}, f"Reloaded {reloaded} linked model(s).")
-        return {"FINISHED"}
-
-
-class SelectLinkFilepath(bpy.types.Operator):
-    bl_idname = "bim.select_link_filepath"
-    bl_label = "Select Link File Path"
-    bl_options = {"REGISTER", "UNDO", "INTERNAL"}
-    bl_description = "Select a new file path for the linked model and return to the reload dialog"
-
-    link_index: bpy.props.IntProperty(name="Link Index")
-    filepath: bpy.props.StringProperty(subtype="FILE_PATH", options={"SKIP_SAVE", "HIDDEN"})
-    filter_glob: bpy.props.StringProperty(default="*.ifc", options={"HIDDEN"})
-    # Reload dialog state carried through the file browser round-trip.
-    use_relative_path: bpy.props.BoolProperty(options={"HIDDEN"})
-    use_cache: bpy.props.BoolProperty(options={"HIDDEN"})
-    query: bpy.props.StringProperty(options={"HIDDEN"})
-    exclude: bpy.props.StringProperty(options={"HIDDEN"})
-
-    if TYPE_CHECKING:
-        link_index: int
-        filepath: str
-        filter_glob: str
-        use_relative_path: bool
-        use_cache: bool
-        query: str
-        exclude: str
-
-    def invoke(self, context, event):
-        link = tool.Project.get_project_props().links[self.link_index]
-        self.filepath = tool.Ifc.resolve_uri(link.filepath)
-        context.window_manager.fileselect_add(self)
-        return {"RUNNING_MODAL"}
-
-    def execute(self, context):
-        bpy.ops.bim.reload_link(
-            "INVOKE_DEFAULT",
-            link_index=self.link_index,
-            filepath=self.filepath,
-            use_relative_path=self.use_relative_path,
-            use_cache=self.use_cache,
-            query=self.query,
-            exclude=self.exclude,
-        )
-        return {"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):
@@ -1907,7 +1742,7 @@ class ToggleLinkSelectability(bpy.types.Operator):
         props = tool.Project.get_project_props()
         link = props.links[self.link_index]
         self.library_filepath = tool.Blender.ensure_blender_path_is_abs(
-            tool.Project.get_link_cache_paths(link.filepath, link.query, link.exclude)[0]
+            Path(link.filepath).with_suffix(".ifc.cache.blend")
         )
         link.is_selectable = (is_selectable := not link.is_selectable)
         for collection in self.get_linked_collections():
@@ -1944,7 +1779,7 @@ class ToggleLinkVisibility(bpy.types.Operator):
         props = tool.Project.get_project_props()
         link = props.links[self.link_index]
         self.library_filepath = tool.Blender.ensure_blender_path_is_abs(
-            tool.Project.get_link_cache_paths(link.filepath, link.query, link.exclude)[0]
+            Path(link.filepath).with_suffix(".ifc.cache.blend")
         )
         if self.mode == "WIREFRAME":
             self.toggle_wireframe(link)
@@ -1986,16 +1821,10 @@ class EnableEditingLink(bpy.types.Operator):
     bl_idname = "bim.enable_editing_link"
     bl_label = "Enable Editing Link"
     bl_options = {"REGISTER", "UNDO"}
-    bl_description = "Unlock the link's position for editing. Any movement is saved automatically"
-
-    link_index: bpy.props.IntProperty(name="Link Index", default=-1)
-
-    if TYPE_CHECKING:
-        link_index: int
+    bl_description = "Enable editing link location"
 
     def execute(self, context):
-        props = tool.Project.get_project_props()
-        link = props.active_link if self.link_index == -1 else props.links[self.link_index]
+        link = tool.Project.get_project_props().active_link
         assert link
         link.is_editing = True
         obj = tool.Project.get_link_empty_handle(link)
@@ -2004,25 +1833,70 @@ class EnableEditingLink(bpy.types.Operator):
         return {"FINISHED"}
 
 
-class DisableEditingLink(bpy.types.Operator, tool.Ifc.Operator):
+class DisableEditingLink(bpy.types.Operator):
     bl_idname = "bim.disable_editing_link"
     bl_label = "Disable Editing Link"
     bl_options = {"REGISTER", "UNDO"}
-    bl_description = "Lock the link at its current location"
+    bl_description = "Disable editing link and restore to previously saved location"
 
-    link_index: bpy.props.IntProperty(name="Link Index", default=-1)
-
-    if TYPE_CHECKING:
-        link_index: int
-
-    def _execute(self, context):
-        props = tool.Project.get_project_props()
-        link = props.active_link if self.link_index == -1 else props.links[self.link_index]
+    def execute(self, context):
+        link = tool.Project.get_project_props().active_link
         assert link
         link.is_editing = False
         obj = tool.Project.get_link_empty_handle(link)
         assert obj
-        tool.Project.save_link_transformation(link)
+        obj.matrix_world = tool.Project.calculate_link_matrix(link)
+        tool.Geometry.lock_object(obj)
+        return {"FINISHED"}
+
+
+class EditLink(bpy.types.Operator, tool.Ifc.Operator):
+    bl_idname = "bim.edit_link"
+    bl_label = "Edit Link"
+    bl_options = {"REGISTER", "UNDO"}
+    bl_description = "Disable editing link and restore to previously saved location"
+
+    def _execute(self, context):
+        link = tool.Project.get_project_props().active_link
+        assert link
+        link.is_editing = False
+        obj = tool.Project.get_link_empty_handle(link)
+        assert obj
+        new_obj_matrix = obj.matrix_world
+
+        filepath = Path(tool.Ifc.resolve_uri(link.filepath))
+        with open(filepath.with_suffix(".ifc.cache.json"), "r") as f:
+            metadata = json.load(f)
+
+        rot = ifcopenshell.util.shape_builder.np_rotation_matrix(
+            radians(-float(metadata["model_project_north"])), 4, "Z"
+        )
+        global_matrix = rot @ np.eye(4)
+        global_matrix[:, 3][:3] = [float(o) for o in metadata["model_origin_si"].split(",")]
+
+        gprops = tool.Georeference.get_georeference_props()
+        rot = ifcopenshell.util.shape_builder.np_rotation_matrix(radians(-float(gprops.model_project_north)), 4, "Z")
+        local_matrix = rot @ np.eye(4)
+        local_matrix[:, 3][:3] = [float(o) for o in gprops.model_origin_si.split(",")]
+
+        # obj_matrix is typically calculated as:
+        # obj_matrix = np.linalg.inv(local_matrix) @ transformation @ global_matrix
+        identity_blender_matrix = np.linalg.inv(local_matrix) @ global_matrix
+        if np.allclose(np.array(new_obj_matrix), identity_blender_matrix, atol=1e-5):
+            link.has_transformation = False
+            transformation = ",".join(map(str, np.eye(4).reshape(-1)))
+        else:
+            transformed_global_matrix = local_matrix @ np.array(new_obj_matrix)
+            transformation = transformed_global_matrix @ np.linalg.inv(global_matrix)
+            link.has_transformation = True
+            transformation = ",".join(map(str, transformation.reshape(-1)))
+
+        if tool.Ifc.get():
+            reference = tool.Ifc.get().by_id(link.ifc_definition_id)
+            reference[1] = transformation
+        else:
+            link.transformation = transformation
+
         obj.matrix_world = tool.Project.calculate_link_matrix(link)
         tool.Geometry.lock_object(obj)
 
@@ -2099,6 +1973,7 @@ 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
@@ -2159,13 +2034,23 @@ 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
         # persisted through the save would silently hide them on reload.
         preview_base.discard_pending_previews(context.scene)
-        # Links loaded and visible right now auto-load on the next open.
-        tool.Project.update_linked_models_state()
         # Suffix is appended to the IFC save-success report below so the auto-commit
         # info isn't immediately overwritten by the success message in Blender's
         # status bar (only the latest self.report({"INFO"}, ...) sticks).
@@ -2223,7 +2108,8 @@ 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("//"))
@@ -2257,6 +2143,7 @@ class ExportIFC(bpy.types.Operator, ExportHelper):
             )
 
         bonsai.bim.handler.refresh_ui_data()
+        tool.Autosave.reset_timer()
 
     @classmethod
     def description(cls, context, properties):
@@ -2265,6 +2152,97 @@ 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(self, filepath: str, skip_recent: bool) -> set["rna_enums.OperatorReturnItems"]:
+        return bpy.ops.bim.load_project(
+            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,
+        )
+
+    def execute(self, context):
+        result = self._load(self.autosaved_filepath, skip_recent=True)
+        # Re-point tracking at the original path so future saves write back
+        # to it, not "_autosaved.ifc".
+        tool.Ifc.set_path(self.original_filepath)
+        return result
+
+    def cancel(self, context):
+        # Also reached via Escape or a click outside the dialog, not just Cancel.
+        self._load(self.original_filepath, skip_recent=False)
+
+
+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"
@@ -2273,23 +2251,14 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
 
     query: bpy.props.StringProperty()
     """See ``bim.link_ifc``."""
-    exclude: bpy.props.StringProperty()
-    """See ``bim.link_ifc``."""
 
     if TYPE_CHECKING:
         query: str
-        exclude: str
 
     file: ifcopenshell.file
     meshes: dict[str, bpy.types.Mesh]
     # Material names is derived from diffuse as in 'r-g-b-a'.
     blender_mats: dict[str, bpy.types.Material]
-    # Materials appended from external .blend styles, keyed by style id.
-    # None means the style has no loadable external .blend style.
-    external_style_mats: dict[int, Union[bpy.types.Material, None]]
-    # Appended data-blocks keyed by (filepath, data_block_type, name)
-    # so styles sharing the same external material don't append duplicates.
-    appended_external_blocks: dict[tuple[str, str, str], Union[bpy.types.Material, None]]
 
     def invoke(self, context, event):
         # Invoke is for debugging purposes, users are not intended to use this method really.
@@ -2346,9 +2315,6 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
             else:
                 self.elements |= set(self.file.by_type("IfcSpatialElement"))
             self.elements -= set(self.file.by_type("IfcFeatureElement"))
-        if self.exclude:
-            # The set difference a single selector query cannot express.
-            self.elements -= ifcopenshell.util.selector.filter_elements(self.file, self.exclude)
 
         if tool.Loader.settings.false_origin_mode == "MANUAL" and tool.Loader.settings.false_origin:
             tool.Loader.set_manual_blender_offset(self.file)
@@ -2356,7 +2322,7 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
             tool.Loader.guess_false_origin(self.file)
 
         tool.Georeference.set_model_origin()
-        self.json_filepath = str(tool.Project.get_link_cache_paths(self.filepath, self.query, self.exclude)[1])
+        self.json_filepath = self.filepath + ".cache.json"
         data = {
             "model_is_georeferenced": gprops.model_is_georeferenced,
             "model_crs": gprops.model_crs,
@@ -2374,14 +2340,10 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
             "false_origin": pprops.false_origin,
             "project_north": pprops.project_north,
             "query": self.query,
-            "exclude": self.exclude,
         }
         with open(self.json_filepath, "w") as f:
             json.dump(data, f)
 
-        self.external_style_mats = {}
-        self.appended_external_blocks = {}
-
         for settings in tool.Loader.settings.context_settings:
             if not self.elements:
                 break
@@ -2421,10 +2383,8 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
                     mat = tuple(mat)
                     blender_mat = blender_mats.get(mat, None)
                     if not blender_mat:
-                        blender_mat = self.get_external_material(int(mat[4]))
-                        if not blender_mat:
-                            blender_mat = bpy.data.materials.new("Chunk")
-                            blender_mat.diffuse_color = mat[:4]
+                        blender_mat = bpy.data.materials.new("Chunk")
+                        blender_mat.diffuse_color = mat
                         blender_mats[mat] = blender_mat
                     mat_results.append(blender_mat)
 
@@ -2442,16 +2402,11 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
                 while True:  # Main loop.
                     shape = iterator.get()
                     assert isinstance(shape, W.TriangulationElement)
-                    element = self.file.by_id(shape.id)
-                    results.add(element)
+                    results.add(self.file.by_id(shape.id))
                     geometry = shape.geometry
 
-                    # Elements with a lot of geometry benefit from instancing to save memory.
-                    # Multi-layer elements also take this path as they need their own
-                    # local-space mesh to be sliced into per-layer materials.
-                    if ifcopenshell.util.shape.get_faces(geometry).shape[0] > 333 or self.is_multilayer_element(
-                        element
-                    ):  # 333 tris
+                    # Elements with a lot of geometry benefit from instancing to save memory
+                    if ifcopenshell.util.shape.get_faces(geometry).shape[0] > 333:  # 333 tris
                         self.process_occurrence(shape)
                         if not iterator.next():
                             if not chunked_verts:
@@ -2468,15 +2423,9 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
 
                     ms = np.vstack([default_mat, ifcopenshell.util.shape.get_material_colors(shape.geometry)])
                     mi = ifcopenshell.util.shape.get_faces_material_style_ids(shape.geometry)
-                    # Style ids ride along as a 5th column so styles with
-                    # external .blend materials survive the per-color dedup.
-                    style_ids = np.zeros((len(ms), 1))
                     for geom_material_idx, geom_material in enumerate(shape.geometry.materials):
                         if not geom_material.instance_id():
                             ms[geom_material_idx + 1] = (0.8, 0.8, 0.8, 1)
-                        elif self.get_external_material(geom_material.instance_id()):
-                            style_ids[geom_material_idx + 1] = geom_material.instance_id()
-                    ms = np.hstack((ms, style_ids))
                     chunked_materials.append(ms)
                     chunked_material_ids.append(mi + material_offset + 1)
                     material_offset += len(ms)
@@ -2563,14 +2512,12 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
                     diffuse = (material.diffuse.r(), material.diffuse.g(), material.diffuse.b(), alpha)
                 else:
                     diffuse = (0.8, 0.8, 0.8, 1)  # Blender's default material
-                blender_mat = self.get_external_material(material.instance_id())
+                material_name = f"{diffuse[0]}-{diffuse[1]}-{diffuse[2]}-{diffuse[3]}"
+                blender_mat = self.blender_mats.get(material_name, None)
                 if not blender_mat:
-                    material_name = f"{diffuse[0]}-{diffuse[1]}-{diffuse[2]}-{diffuse[3]}"
-                    blender_mat = self.blender_mats.get(material_name, None)
-                    if not blender_mat:
-                        blender_mat = bpy.data.materials.new(material_name)
-                        blender_mat.diffuse_color = diffuse
-                        self.blender_mats[material_name] = blender_mat
+                    blender_mat = bpy.data.materials.new(material_name)
+                    blender_mat.diffuse_color = diffuse
+                    self.blender_mats[material_name] = blender_mat
                 slot_index = mesh.materials.find(material.name)
                 if slot_index == -1:
                     mesh.materials.append(blender_mat)
@@ -2583,8 +2530,6 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
             mesh.polygons.foreach_set("material_index", material_index)
             mesh.update()
 
-            mesh = tool.Loader.slice_layerset_mesh(element, mesh, style_to_material=self.get_style_material)
-
             self.meshes[geometry.id] = mesh
 
         obj = bpy.data.objects.new(tool.Loader.get_name(element), mesh)
@@ -2597,88 +2542,6 @@ class LoadLinkedProject(bpy.types.Operator, ImportHelper):
 
         self.collection.objects.link(obj)
 
-    def get_external_material(self, style_id: int) -> Union[bpy.types.Material, None]:
-        """Get the Blender material referenced by a style's external .blend style, if it has one.
-
-        The material is appended from the external .blend file on first use and
-        cached, so it ends up saved inside the link's .cache.blend.
-        """
-        if not style_id:
-            return None
-        if style_id in self.external_style_mats:
-            return self.external_style_mats[style_id]
-
-        material = None
-        # instance_id may also refer to an IfcMaterial when the item has
-        # a material but no style, hence the class check.
-        style = self.file.by_id(style_id)
-        external = None
-        if style.is_a("IfcSurfaceStyle"):
-            external = next((s for s in style.Styles if s.is_a("IfcExternallyDefinedSurfaceStyle")), None)
-
-        if (
-            external
-            and external.Location
-            and external.Location.endswith(".blend")
-            and external.Identification
-            and "/" in external.Identification
-        ):
-            location = Path(external.Location)
-            if not location.is_absolute():
-                # Relative locations are relative to the linked IFC, not the host.
-                location = Path(self.filepath).parent / location
-            data_block_type, data_block = external.Identification.split("/", 1)
-            key = (str(location), data_block_type, data_block)
-            if key in self.appended_external_blocks:
-                material = self.appended_external_blocks[key]
-            elif not location.exists():
-                print(f"WARNING. External style file not found for {style}: '{location}'")
-                self.appended_external_blocks[key] = None
-            else:
-                db = tool.Blender.append_data_block(str(location), data_block_type, data_block)
-                material = db["data_block"]
-                if not isinstance(material, bpy.types.Material):
-                    print(f"WARNING. Failed to load external style for {style}: {db['msg'] or 'not a material'}")
-                    material = None
-                else:
-                    # The source .blend may have been authored in a Bonsai session -
-                    # unlink any stale IFC id so it's not misinterpreted here or in the host.
-                    tool.Style.get_material_style_props(material).ifc_definition_id = 0
-                self.appended_external_blocks[key] = material
-
-        self.external_style_mats[style_id] = material
-        return material
-
-    def is_multilayer_element(self, element: ifcopenshell.entity_instance) -> bool:
-        material = ifcopenshell.util.element.get_material(element)
-        return bool(
-            material and material.is_a("IfcMaterialLayerSetUsage") and len(material.ForLayerSet.MaterialLayers) > 1
-        )
-
-    def get_style_material(self, style: ifcopenshell.entity_instance) -> Union[bpy.types.Material, None]:
-        """Resolve a style to a Blender material for slice_layerset_mesh.
-
-        Prefers the style's external .blend material, falling back to a flat
-        diffuse material as used for the rest of the linked geometry.
-        """
-        if material := self.get_external_material(style.id()):
-            return material
-        # IfcSurfaceStyleRendering is a subclass of IfcSurfaceStyleShading.
-        shading = next((s for s in style.Styles if s.is_a("IfcSurfaceStyleShading")), None)
-        if shading:
-            colour = shading.SurfaceColour
-            alpha = 1.0 - (getattr(shading, "Transparency", None) or 0.0)
-            diffuse = (colour.Red, colour.Green, colour.Blue, alpha)
-        else:
-            diffuse = (0.8, 0.8, 0.8, 1.0)
-        material_name = f"{diffuse[0]}-{diffuse[1]}-{diffuse[2]}-{diffuse[3]}"
-        material = self.blender_mats.get(material_name, None)
-        if not material:
-            material = bpy.data.materials.new(material_name)
-            material.diffuse_color = diffuse
-            self.blender_mats[material_name] = material
-        return material
-
     def create_object(
         self,
         verts: np.ndarray,
@@ -2752,7 +2615,7 @@ class QueryLinkedElement(bpy.types.Operator):
 
         guid = tool.Project.Link.get_guid_by_face_index(obj, face_index)
         assert guid is not None
-        tool.Project.Link.select_linked_element(context, obj, guid, instance_matrix)
+        tool.Project.Link.select_linked_element(context, obj, guid)
 
         self.report({"INFO"}, f"Loaded data for {guid}")
         ProjectDecorator.install(bpy.context)
@@ -2877,27 +2740,6 @@ class AppendInspectedLinkedElement(AppendLibraryElement):
         if element_type and tool.Ifc.get_object(element_type) is None:
             self.import_type_from_ifc(element_type, context)
 
-        # If the link was moved, place the appended element where the link
-        # is displayed rather than at its original coordinates.
-        obj = tool.Ifc.get_object(element)
-        if isinstance(obj, bpy.types.Object):
-            # Prefer matching the link by the queried instance's root empty -
-            # the same file may be linked several times (different queries)
-            # and moved to different locations.
-            root = props.queried_obj_root
-            linked_filepath = Path(queried_obj["ifc_filepath"])
-            link_match = None
-            for link in props.links:
-                if root is not None and tool.Project.get_link_empty_handle(link) == root:
-                    link_match = link
-                    break
-                if link_match is None and Path(tool.Ifc.resolve_uri(link.filepath)) == linked_filepath:
-                    link_match = link
-            if link_match:
-                delta = tool.Project.calculate_link_delta_matrix(link_match)
-                if not delta.is_identity:
-                    obj.matrix_world = delta @ obj.matrix_world
-
         return {"FINISHED"}
 
 

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

@@ -261,21 +261,8 @@ class Link(PropertyGroup):
         default=0,
     )
     query: StringProperty(
-        name="Include",
-        description="Selector query for the elements to load from the linked model",
-        default="",
-    )
-    exclude: StringProperty(
-        name="Exclude",
-        description="Selector query whose matches are excluded when loading the linked model",
-        default="",
-    )
-    display_name: StringProperty(
-        name="Name",
-        description=(
-            "Optional display name to tell links apart (e.g. when the same file "
-            "is linked several times). Shows the file path when empty"
-        ),
+        name="Query",
+        description="Selector query used to filter elements when loading the linked model",
         default="",
     )
 
@@ -294,8 +281,6 @@ class Link(PropertyGroup):
         empty_handle: Union[bpy.types.Object, None]
         ifc_definition_id: int
         query: str
-        exclude: str
-        display_name: str
 
 
 class EditedObj(PropertyGroup):

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

@@ -492,13 +492,17 @@ class BIM_PT_links(Panel):
 
         row = self.layout.row(align=True)
         row.operator("bim.link_ifc")
-        row.operator("bim.reload_all_links", text="", icon="FILE_REFRESH")
         if self.props.links:
             if self.props.active_link:
                 row = self.layout.row(align=True)
                 row.alignment = "RIGHT"
                 index = self.props.active_link_index
                 if self.props.active_link.is_loaded:
+                    if self.props.active_link.is_editing:
+                        row.operator("bim.edit_link", text="", icon="CHECKMARK")
+                        row.operator("bim.disable_editing_link", text="", icon="CANCEL")
+                    else:
+                        row.operator("bim.enable_editing_link", text="", icon="GREASEPENCIL")
                     row.operator("bim.select_linked_model_element", icon="VIEWZOOM", text="")
                     row.operator("bim.select_link_handle", text="", icon="OBJECT_DATA").link_index = index
                     row.operator("bim.unload_link", text="", icon="UNLINKED").link_index = index
@@ -639,12 +643,7 @@ class BIM_UL_links(UIList):
             if item.has_transformation:
                 row.label(text="", icon="OBJECT_ORIGIN")
 
-            # Double-click to rename; shows the file path while unset.
-            row.prop(item, "display_name", text="", emboss=False, placeholder=item.filepath)
-            if item.is_editing:
-                row.operator("bim.disable_editing_link", text="", icon="UNLOCKED", emboss=False).link_index = index
-            else:
-                row.operator("bim.enable_editing_link", text="", icon="LOCKED", emboss=False).link_index = index
+            row.label(text=item.filepath)
             icon = "RESTRICT_SELECT_OFF" if item.is_selectable else "RESTRICT_SELECT_ON"
             row.operator("bim.toggle_link_selectability", text="", icon=icon, emboss=False).link_index = index
             icon = "CUBE" if item.is_wireframe else "MESH_CUBE"
@@ -656,7 +655,7 @@ class BIM_UL_links(UIList):
             op.link_index = index
             op.mode = "VISIBLE"
         else:
-            row.prop(item, "display_name", text="", emboss=False, placeholder=item.filepath)
+            row.label(text=item.filepath)
 
 
 class BIM_PT_purge(Panel):

src/bonsai/bonsai/bim/ui.py

@@ -577,6 +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",
@@ -689,6 +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"]
@@ -837,6 +877,12 @@ class BIM_ADDON_preferences(bpy.types.AddonPreferences):
     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:")

src/bonsai/bonsai/core/drawing.py

@@ -302,23 +302,25 @@ def add_drawing(
         context=drawing.get_body_context(),
         ifc_representation_class=None,
     )
-    
+
     drawings_parent_group = None
     for group in ifc.get().by_type("IfcGroup"):
         if group.Name == "DRAWINGS" and group.ObjectType == "DRAWINGS":
             drawings_parent_group = group
             break
-    
+
     if not drawings_parent_group:
         drawings_parent_group = ifc.run("group.add_group")
-        ifc.run("group.edit_group", group=drawings_parent_group, attributes={"Name": "DRAWINGS", "ObjectType": "DRAWINGS"})
-    
+        ifc.run(
+            "group.edit_group", group=drawings_parent_group, attributes={"Name": "DRAWINGS", "ObjectType": "DRAWINGS"}
+        )
+
     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":
@@ -355,7 +357,7 @@ def add_drawing(
         if document.Name == "DRAWINGS" and document.Scope == "DRAWINGS":
             drawings_parent_document = document
             break
-    
+
     if not drawings_parent_document:
         drawings_parent_document = ifc.run("document.add_information")
         if ifc.get_schema() == "IFC2X3":
@@ -363,7 +365,7 @@ def add_drawing(
         else:
             attributes = {"Identification": "DRAWINGS", "Name": "DRAWINGS", "Scope": "DRAWINGS"}
         ifc.run("document.edit_information", information=drawings_parent_document, attributes=attributes)
-    
+
     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)
@@ -392,17 +394,19 @@ 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 = None
     for parent_group in ifc.get().by_type("IfcGroup"):
         if parent_group.Name == "DRAWINGS" and parent_group.ObjectType == "DRAWINGS":
             drawings_parent_group = parent_group
             break
-    
+
     if not drawings_parent_group:
         drawings_parent_group = ifc.run("group.add_group")
-        ifc.run("group.edit_group", group=drawings_parent_group, attributes={"Name": "DRAWINGS", "ObjectType": "DRAWINGS"})
-    
+        ifc.run(
+            "group.edit_group", group=drawings_parent_group, attributes={"Name": "DRAWINGS", "ObjectType": "DRAWINGS"}
+        )
+
     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])
@@ -427,7 +431,7 @@ def duplicate_drawing(
         if document.Name == "DRAWINGS" and document.Scope == "DRAWINGS":
             drawings_parent_document = document
             break
-    
+
     if not drawings_parent_document:
         drawings_parent_document = ifc.run("document.add_information")
         if ifc.get_schema() == "IFC2X3":

src/bonsai/bonsai/core/product.py

@@ -50,14 +50,15 @@ def copy_z_rotation_to_selected(
     flip: bool = False,
 ) -> int:
     """Apply ``active``'s Z-Euler rotation to each target."""
-    source_z = surveyor.get_z_rotation(active)
+    source_z = surveyor.get_z_rotation(active)  # ty: ignore[missing-argument]
     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:
+        target_z = surveyor.get_z_rotation(obj)  # ty: ignore[missing-argument]
+        if abs(_z_rotation_diff(target_z, source_z)) < Z_ROTATION_ALIGNMENT_TOLERANCE:
             continue
-        surveyor.set_z_rotation(obj, source_z)
+        surveyor.set_z_rotation(obj, source_z)  # ty: ignore[missing-argument]
         rotated += 1
         if ifc.get_entity(obj) is not None:
             bonsai.core.geometry.edit_object_placement(ifc, geometry, surveyor, obj=obj)

src/bonsai/bonsai/core/tool.py

@@ -804,7 +804,7 @@ 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
 
 

src/bonsai/bonsai/tool/__init__.py

@@ -80,3 +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

src/bonsai/bonsai/tool/autosave.py

@@ -0,0 +1,188 @@
+# 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 atexit
+import logging
+import os
+from collections.abc import Callable
+from pathlib import Path
+from typing import Union
+
+import bpy
+
+import bonsai.tool as tool
+from bonsai.bim import export_ifc
+from bonsai.bim.module.model import preview_base
+
+AUTOSAVING_SUFFIX = "_autosaving.ifc"
+AUTOSAVED_SUFFIX = "_autosaved.ifc"
+
+_timer_callback: Union[Callable[[], None], None] = None
+# See cleanup_stale_autosave() for why this is a cached plain string rather
+# than looked up live.
+_active_ifc_path_cache: Union[str, None] = None
+
+
+class Autosave:
+    @classmethod
+    def get_paths(cls, ifc_path: Union[str, Path]) -> tuple[Path, Path, Path]:
+        path = Path(ifc_path)
+        stem = path.stem if path.suffix.lower() == ".ifc" else path.name
+        parent = path.parent
+        main_path = path if path.suffix.lower() == ".ifc" else parent / f"{stem}.ifc"
+        autosaving_path = parent / f"{stem}{AUTOSAVING_SUFFIX}"
+        autosaved_path = parent / f"{stem}{AUTOSAVED_SUFFIX}"
+        return main_path, autosaving_path, autosaved_path
+
+    @classmethod
+    def get_active_ifc_path(cls) -> Union[Path, None]:
+        props = tool.Blender.get_bim_props()
+        if not props.ifc_file:
+            return None
+        path = tool.Blender.ensure_blender_path_is_abs(Path(props.ifc_file))
+        if path.suffix.lower() != ".ifc":
+            return None
+        return path
+
+    @classmethod
+    def _update_active_ifc_path_cache(cls) -> None:
+        global _active_ifc_path_cache
+        ifc_path = cls.get_active_ifc_path()
+        _active_ifc_path_cache = ifc_path.as_posix() if ifc_path is not None else None
+
+    @classmethod
+    def is_enabled(cls) -> bool:
+        return bool(tool.Blender.get_addon_preferences().autosave_enabled)
+
+    @classmethod
+    def get_interval_seconds(cls) -> float:
+        minutes = tool.Blender.get_addon_preferences().autosave_interval_minutes
+        return max(1.0, float(minutes) * 60.0)
+
+    @classmethod
+    def is_eligible(cls) -> bool:
+        return cls.is_enabled() and tool.Ifc.get() is not None and cls.get_active_ifc_path() is not None
+
+    @classmethod
+    def cancel_timer(cls) -> None:
+        global _timer_callback
+        if _timer_callback is not None and bpy.app.timers.is_registered(_timer_callback):
+            bpy.app.timers.unregister(_timer_callback)
+        _timer_callback = None
+
+    @classmethod
+    def reset_timer(cls) -> None:
+        cls.cancel_timer()
+        cls._update_active_ifc_path_cache()
+        if not cls.is_eligible():
+            return
+
+        def on_timer() -> None:
+            cls._on_timer_expired()
+            return None
+
+        global _timer_callback
+        _timer_callback = on_timer
+        bpy.app.timers.register(on_timer, first_interval=cls.get_interval_seconds())
+
+    @classmethod
+    def _on_timer_expired(cls) -> None:
+        if not cls.is_eligible():
+            return
+
+        prefs = tool.Blender.get_addon_preferences()
+        bim_props = tool.Blender.get_bim_props()
+
+        if bim_props.is_dirty:
+            if prefs.autosave_mode == "PROMPT":
+                bpy.ops.bim.autosave_prompt("INVOKE_DEFAULT")
+            elif prefs.autosave_mode == "BACKUP":
+                try:
+                    cls.perform_backup(bpy.context)
+                except Exception as error:
+                    print(f"Bonsai: autosave backup failed: {error}")
+        cls.reset_timer()
+
+    @classmethod
+    def perform_backup(cls, context: bpy.types.Context) -> None:
+        ifc_path = cls.get_active_ifc_path()
+        if ifc_path is None:
+            return
+
+        _, autosaving_path, autosaved_path = cls.get_paths(ifc_path)
+        autosaving_path.parent.mkdir(parents=True, exist_ok=True)
+
+        tool.Parametric.commit_pending_edits()
+        preview_base.discard_pending_previews(context.scene)
+
+        logger = logging.getLogger("ExportIFC")
+        output_file = autosaving_path.as_posix().replace("\\", "/")
+        settings = export_ifc.IfcExportSettings.factory(context, output_file, logger)
+        export_ifc.IfcExporter(settings).export()
+
+        try:
+            os.replace(autosaving_path, autosaved_path)
+        except OSError:
+            if autosaving_path.is_file():
+                autosaving_path.unlink(missing_ok=True)
+            raise
+
+    @classmethod
+    def get_newer_autosaved_path(cls, ifc_path: Union[str, Path]) -> Union[str, None]:
+        path = Path(ifc_path)
+        if path.suffix.lower() != ".ifc" or not path.is_file():
+            return None
+
+        _, _, autosaved_path = cls.get_paths(path)
+        if not autosaved_path.is_file():
+            return None
+        if autosaved_path.stat().st_mtime > path.stat().st_mtime:
+            return autosaved_path.as_posix().replace("\\", "/")
+        return None
+
+    @classmethod
+    def cleanup_stale_autosave(cls) -> None:
+        """Remove the active IFC's autosave file(s) on a graceful shutdown.
+
+        Registered via `atexit`, which only runs on a normal interpreter
+        shutdown - never on an actual crash. So a deliberate quit (whether
+        the user saved or chose "don't save") clears the recovery file and
+        won't prompt on next startup, while a genuine crash leaves it in
+        place for recovery, since no atexit callbacks fire then.
+
+        Deliberately reads only `_active_ifc_path_cache` - a plain string
+        kept up to date by `reset_timer()` - rather than touching `bpy` here.
+        By the time `atexit` fires, Blender's own C++ side is torn down far
+        enough that even reading `bpy.context.scene` aborts the process
+        (std::bad_optional_access) instead of raising a catchable exception.
+        """
+        if _active_ifc_path_cache is None:
+            return
+        try:
+            _, autosaving_path, autosaved_path = cls.get_paths(_active_ifc_path_cache)
+            autosaving_path.unlink(missing_ok=True)
+            autosaved_path.unlink(missing_ok=True)
+        except Exception:
+            pass
+
+
+atexit.register(Autosave.cleanup_stale_autosave)

src/bonsai/bonsai/tool/loader.py

@@ -23,7 +23,7 @@ import os
 import re
 from math import atan, radians
 from pathlib import Path
-from typing import Any, Callable, Optional, Union, cast
+from typing import Any, Optional, Union, cast
 
 import bmesh
 import bpy
@@ -1073,19 +1073,7 @@ class Loader(bonsai.core.tool.Loader):
         return mesh
 
     @classmethod
-    def slice_layerset_mesh(
-        cls,
-        element: ifcopenshell.entity_instance,
-        mesh: bpy.types.Mesh,
-        style_to_material: Optional[Callable[[ifcopenshell.entity_instance], Union[bpy.types.Material, None]]] = None,
-    ) -> bpy.types.Mesh:
-        """Bisect a layerset element's mesh at layer boundaries and assign each layer its material style.
-
-        :param style_to_material: Callback resolving an IfcSurfaceStyle to a Blender material.
-            Defaults to the IFC-linked material, which only works for the actively edited project.
-        """
-        if style_to_material is None:
-            style_to_material = tool.Ifc.get_object
+    def slice_layerset_mesh(cls, element: ifcopenshell.entity_instance, mesh: bpy.types.Mesh) -> bpy.types.Mesh:
         if not (material := ifcopenshell.util.element.get_material(element)):
             return mesh
         elif material.is_a("IfcMaterialLayerSetUsage"):
@@ -1133,8 +1121,7 @@ class Loader(bonsai.core.tool.Loader):
                 continue
             if (material_index := styles.get(style, None)) is None:
                 material_index = len(mesh.materials)
-                mesh.materials.append(style_to_material(style))
-                styles[style] = material_index
+                mesh.materials.append(tool.Ifc.get_object(style))
             if i == last_i:
                 for face in bisect_geom["geom"]:
                     if isinstance(face, bmesh.types.BMFace):

src/bonsai/bonsai/tool/model.py

@@ -59,6 +59,7 @@ from ifcopenshell.util.shape_builder import ShapeBuilder, np_to_3d
 from mathutils import Matrix, Vector
 
 import bonsai.core.geometry
+import bonsai.core.model
 import bonsai.core.tool
 import bonsai.tool as tool
 from bonsai.bim import import_ifc

src/bonsai/bonsai/tool/project.py

@@ -18,7 +18,6 @@
 
 from __future__ import annotations
 
-import hashlib
 import json
 import os
 import shutil
@@ -90,90 +89,10 @@ class Project(bonsai.core.tool.Project):
         else:
             link.empty_handle = empty
 
-    @classmethod
-    def get_link_cache_paths(cls, filepath: Union[Path, str], query: str, exclude: str = "") -> tuple[Path, Path]:
-        """Get the (blend, json) cache paths for a linked model's filter.
-
-        Cache files are per-filter so the same IFC file can be linked several
-        times with different include/exclude queries without the caches
-        overwriting each other. An empty filter keeps the legacy un-suffixed
-        names, and an include-only filter keeps the pre-exclude hash so
-        existing caches stay valid.
-        """
-        filepath = Path(filepath)
-        if not query and not exclude:
-            suffix = ""
-        elif not exclude:
-            suffix = "." + hashlib.md5(query.encode("utf-8")).hexdigest()[:8]
-        else:
-            suffix = "." + hashlib.md5(f"{query}\0{exclude}".encode("utf-8")).hexdigest()[:8]
-        return (
-            filepath.with_suffix(f".ifc.cache{suffix}.blend"),
-            filepath.with_suffix(f".ifc.cache{suffix}.json"),
-        )
-
-    @classmethod
-    def encode_link_filter(
-        cls, query: str, exclude: str, loaded: bool = False, display_name: str = ""
-    ) -> Union[str, None]:
-        """Serialize a link's filter and state for IfcDocumentReference.Description.
-
-        A plain include query is stored as-is (backwards compatible); an
-        exclude, a loaded state or a display name promotes the value to a
-        small JSON blob. The loaded flag makes the link auto-load on the
-        next project open.
-        """
-        if exclude or loaded or display_name:
-            return json.dumps({"include": query, "exclude": exclude, "loaded": loaded, "name": display_name})
-        return query or None
-
-    @classmethod
-    def decode_link_filter(cls, description: Union[str, None]) -> tuple[str, str, bool, str]:
-        """Get (query, exclude, loaded, display_name) from a Description written by encode_link_filter."""
-        if not description:
-            return "", "", False, ""
-        if description.startswith("{"):
-            try:
-                data = json.loads(description)
-                if isinstance(data, dict):
-                    return (
-                        data.get("include", "") or "",
-                        data.get("exclude", "") or "",
-                        bool(data.get("loaded", False)),
-                        data.get("name", "") or "",
-                    )
-            except json.JSONDecodeError:
-                pass
-        return description, "", False, ""
-
-    @classmethod
-    def update_linked_models_state(cls) -> None:
-        """Persist each link's loaded/visible state onto its document reference.
-
-        Called at IFC save time so links that were loaded and visible
-        auto-load the next time the project is opened.
-        """
-        if not tool.Ifc.get():
-            return
-        for link in cls.get_project_props().links:
-            if not link.ifc_definition_id:
-                continue
-            try:
-                reference = tool.Ifc.get().by_id(link.ifc_definition_id)
-            except RuntimeError:
-                continue
-            if hasattr(reference, "Description"):
-                reference.Description = cls.encode_link_filter(
-                    link.query,
-                    link.exclude,
-                    loaded=link.is_loaded and not link.is_hidden,
-                    display_name=link.display_name,
-                )
-
     @classmethod
     def calculate_link_matrix(cls, link: Link) -> Matrix:
         filepath = Path(tool.Ifc.resolve_uri(link.filepath))
-        with open(cls.get_link_cache_paths(filepath, link.query, link.exclude)[1], "r") as f:
+        with open(filepath.with_suffix(".ifc.cache.json"), "r") as f:
             metadata = json.load(f)
 
         rot = ifcopenshell.util.shape_builder.np_rotation_matrix(
@@ -198,86 +117,6 @@ class Project(bonsai.core.tool.Project):
         local_matrix[:, 3][:3] = [float(o) for o in gprops.model_origin_si.split(",")]
         return Matrix(np.linalg.inv(local_matrix) @ global_matrix)
 
-    @classmethod
-    def get_link_transformation_matrix(cls, link: Link) -> Union[npt.NDArray[np.float64], None]:
-        """Get the link's saved 4x4 transformation in model coordinates, or None when identity."""
-        if tool.Ifc.get():
-            transformation = tool.Ifc.get().by_id(link.ifc_definition_id)[1]  # Identification
-        else:
-            transformation = link.transformation
-        if not transformation:
-            return None
-        matrix = np.fromstring(transformation, sep=",", dtype=np.float64).reshape(4, 4)
-        if np.allclose(matrix, np.eye(4)):
-            return None
-        return matrix
-
-    @classmethod
-    def calculate_link_delta_matrix(cls, link: Link) -> Matrix:
-        """Get the matrix mapping the link's unmoved world positions to its moved ones.
-
-        Returns identity when the link has no saved transformation.
-        """
-        if tool.Ifc.get():
-            transformation = tool.Ifc.get().by_id(link.ifc_definition_id)[1]  # Identification
-        else:
-            transformation = link.transformation
-
-        if not transformation:
-            return Matrix.Identity(4)
-        transformation = np.fromstring(transformation, sep=",", dtype=np.float64).reshape(4, 4)
-        if np.allclose(transformation, np.eye(4)):
-            return Matrix.Identity(4)
-
-        gprops = tool.Georeference.get_georeference_props()
-        rot = ifcopenshell.util.shape_builder.np_rotation_matrix(radians(-float(gprops.model_project_north)), 4, "Z")
-        local_matrix = rot @ np.eye(4)
-        local_matrix[:, 3][:3] = [float(o) for o in gprops.model_origin_si.split(",")]
-
-        # Link empty matrix is inv(local) @ transformation @ global (see
-        # calculate_link_matrix), so moved = inv(local) @ T @ local @ unmoved.
-        return Matrix(np.linalg.inv(local_matrix) @ transformation @ local_matrix)
-
-    @classmethod
-    def save_link_transformation(cls, link: Link) -> None:
-        """Persist the link handle's current world matrix as the link's saved transformation."""
-        obj = cls.get_link_empty_handle(link)
-        assert obj
-        new_obj_matrix = np.array(obj.matrix_world)
-
-        filepath = Path(tool.Ifc.resolve_uri(link.filepath))
-        with open(cls.get_link_cache_paths(filepath, link.query, link.exclude)[1], "r") as f:
-            metadata = json.load(f)
-
-        rot = ifcopenshell.util.shape_builder.np_rotation_matrix(
-            radians(-float(metadata["model_project_north"])), 4, "Z"
-        )
-        global_matrix = rot @ np.eye(4)
-        global_matrix[:, 3][:3] = [float(o) for o in metadata["model_origin_si"].split(",")]
-
-        gprops = tool.Georeference.get_georeference_props()
-        rot = ifcopenshell.util.shape_builder.np_rotation_matrix(radians(-float(gprops.model_project_north)), 4, "Z")
-        local_matrix = rot @ np.eye(4)
-        local_matrix[:, 3][:3] = [float(o) for o in gprops.model_origin_si.split(",")]
-
-        # obj_matrix is typically calculated as:
-        # obj_matrix = np.linalg.inv(local_matrix) @ transformation @ global_matrix
-        identity_blender_matrix = np.linalg.inv(local_matrix) @ global_matrix
-        if np.allclose(new_obj_matrix, identity_blender_matrix, atol=1e-5):
-            link.has_transformation = False
-            transformation = ",".join(map(str, np.eye(4).reshape(-1)))
-        else:
-            transformed_global_matrix = local_matrix @ new_obj_matrix
-            transformation = transformed_global_matrix @ np.linalg.inv(global_matrix)
-            link.has_transformation = True
-            transformation = ",".join(map(str, transformation.reshape(-1)))
-
-        if tool.Ifc.get():
-            reference = tool.Ifc.get().by_id(link.ifc_definition_id)
-            reference[1] = transformation
-        else:
-            link.transformation = transformation
-
     @classmethod
     def append_all_types_from_template(cls, template: str) -> None:
         # TODO refactor
@@ -470,17 +309,11 @@ class Project(bonsai.core.tool.Project):
 
     @classmethod
     def get_linked_models_documents(cls) -> dict[str, ifcopenshell.entity_instance]:
-        """Get linked model documents keyed by resolved absolute filepath (posix form).
-
-        Locations are stored either relative or absolute depending on how the
-        link was created - resolving before keying ensures both forms of the
-        same file match one document.
-        """
         linked_docs = {}
         for doc in tool.Ifc.get().by_type("IfcDocumentInformation"):
             if doc.Scope == "LINKED_MODEL":
                 for reference in tool.Drawing.get_document_references(doc):
-                    linked_docs[Path(tool.Ifc.resolve_uri(reference.Location)).as_posix()] = doc
+                    linked_docs[Path(reference.Location).as_posix()] = doc
                     break
         return linked_docs
 
@@ -488,52 +321,27 @@ class Project(bonsai.core.tool.Project):
     def load_linked_models_from_ifc(cls) -> None:
         links = tool.Project.get_project_props().links
         links.clear()
-        references: list[ifcopenshell.entity_instance] = []
         for doc in tool.Ifc.get().by_type("IfcDocumentInformation"):
             if doc.Scope != "LINKED_MODEL":
                 continue
-            references.extend(tool.Drawing.get_document_references(doc))
-        location_counts: defaultdict[str, int] = defaultdict(int)
-        for reference in references:
-            location_counts[reference.Location] += 1
-        autoload_indices: list[int] = []
-        for reference in references:
-            filepath = reference.Location
-            link = links.add()
-            link.name = filepath
-            link.filepath = filepath
-            link.ifc_definition_id = reference.id()
-            link.has_transformation = False
-            if reference[1]:
-                m = np.fromstring(reference[1], sep=",", dtype=np.float64).reshape(4, 4)
-                link.has_transformation = not np.allclose(m, np.eye(4))
-            # The selector filter used at link time is persisted per
-            # reference in its Description (IFC4+); restore it so
-            # Reload/Load replay the filter.
-            query, exclude, loaded, display_name = cls.decode_link_filter(getattr(reference, "Description", None))
-            if not query and not exclude and location_counts[filepath] == 1:
-                # Fall back to the legacy sidecar cache JSON where older
-                # versions persisted the query. Only unambiguous: with
-                # several links to one file the shared JSON can't say
-                # which link it belonged to.
+            for reference in tool.Drawing.get_document_references(doc):
+                filepath = reference.Location
+                link = links.add()
+                link.name = filepath
+                link.filepath = filepath
+                link.ifc_definition_id = reference.id()
+                link.has_transformation = False
+                if reference[1]:
+                    m = np.fromstring(reference[1], sep=",", dtype=np.float64).reshape(4, 4)
+                    link.has_transformation = not np.allclose(m, np.eye(4))
+                # The selector query used at link time is persisted only in the
+                # sidecar cache JSON; restore it so Reload/Load replay the filter.
                 json_filepath = Path(tool.Ifc.resolve_uri(filepath)).with_suffix(".ifc.cache.json")
                 if json_filepath.exists():
                     try:
-                        query = json.loads(json_filepath.read_text()).get("query", "")
+                        link.query = json.loads(json_filepath.read_text()).get("query", "")
                     except (OSError, json.JSONDecodeError):
                         pass
-            link.query = query
-            link.exclude = exclude
-            link.display_name = display_name
-            if loaded:
-                autoload_indices.append(len(links) - 1)
-
-        # Links that were loaded and visible at save time load automatically.
-        for i in autoload_indices:
-            if not Path(tool.Ifc.resolve_uri(links[i].filepath)).exists():
-                print(f"WARNING: Not auto-loading missing linked model: {links[i].filepath}")
-                continue
-            bpy.ops.bim.load_link(link_index=i)
 
     @classmethod
     def get_project_library_elements(
@@ -1050,16 +858,9 @@ class Project(bonsai.core.tool.Project):
 
             selected_vertices = [obj.matrix_world @ mesh.vertices[vi].co for vi in vert_map]
             for polygon in guid_polygons:
+                selected_tris.append(tuple(vert_map[vi] for vi in polygon.vertices))
                 selected_edges.extend(tuple([vert_map[vi] for vi in e]) for e in polygon.edge_keys)
 
-            # Polygons are not necessarily triangles (e.g. layerset-sliced
-            # meshes contain ngons), so triangles come from the loop triangles.
-            mesh.calc_loop_triangles()
-            polygon_range = range(*slice_.indices(len(mesh.polygons)))
-            for tri in mesh.loop_triangles:
-                if tri.polygon_index in polygon_range:
-                    selected_tris.append(tuple(vert_map[vi] for vi in tri.vertices))
-
             obj["selected_vertices"] = selected_vertices
             obj["selected_edges"] = selected_edges
             obj["selected_tris"] = selected_tris
@@ -1096,9 +897,11 @@ class Project(bonsai.core.tool.Project):
             from bonsai.bim.module.project.data import LinksData
             from bonsai.bim.module.project.decorator import ProjectDecorator
 
-            # `instance_matrix` is the world matrix of the hit collection instance
-            # from `ray_cast` (link empty matrix included). Without it, the root
-            # empty is resolved as the collection's only instance.
+            # Not sure if there's a difference between `instance_matrix` coming from `ray_cast`
+            # and usual `matrix_world`, maybe we can just get it from object always.
+            if instance_matrix is None:
+                instance_matrix = obj.matrix_world
+
             cls.deselect_queried_linked_element()
             cls.set_queried_linked_element(obj, guid, instance_matrix)
             cls.select_linked_element_geom(obj, guid)
@@ -1155,7 +958,7 @@ class Project(bonsai.core.tool.Project):
             ProjectDecorator.install(context)
 
         @classmethod
-        def set_queried_linked_element(cls, obj: bpy.types.Object, guid: str, instance_matrix: Matrix | None) -> None:
+        def set_queried_linked_element(cls, obj: bpy.types.Object, guid: str, instance_matrix: Matrix) -> None:
             props = tool.Project.get_project_props()
             props.queried_obj = obj
             props.queried_obj_root = cls.find_obj_root(obj, instance_matrix)
@@ -1174,22 +977,17 @@ class Project(bonsai.core.tool.Project):
                     del obj[field]
 
         @classmethod
-        def find_obj_root(cls, obj: bpy.types.Object, matrix: Matrix | None) -> bpy.types.Object | None:
+        def find_obj_root(cls, obj: bpy.types.Object, matrix: Matrix) -> bpy.types.Object | None:
             collections = set(obj.users_collection)
-            candidates = [
-                o
-                for o in bpy.data.objects
-                if o.type == "EMPTY" and o.instance_type == "COLLECTION" and o.instance_collection in collections
-            ]
-            if matrix is not None:
-                # `matrix` is the instance's world matrix - the instancing
-                # empty's matrix combined with the object's own local matrix
-                # (non-identity for instanced occurrence objects).
-                for o in candidates:
-                    if np.allclose(matrix, np.array(o.matrix_world) @ np.array(obj.matrix_world), atol=1e-4):
-                        return o
-            if len(candidates) == 1:
-                return candidates[0]
+            for o in bpy.data.objects:
+                if (
+                    o.type != "EMPTY"
+                    or o.instance_type != "COLLECTION"
+                    or o.instance_collection not in collections
+                    or not np.allclose(matrix, o.matrix_world, atol=1e-4)
+                ):
+                    continue
+                return o
 
         class SelectedGeometry(NamedTuple):
             selected_vertices: list[tuple[float, float, float]]
@@ -1198,11 +996,8 @@ class Project(bonsai.core.tool.Project):
 
         @classmethod
         def get_selected_geometry(cls, obj: bpy.types.Object) -> SelectedGeometry:
-            # ID properties are returned as IDPropertyArrays (the whole
-            # property when empty, the items otherwise), which the GPU module
-            # rejects as batch indices - convert to plain tuples.
             return cls.SelectedGeometry(
-                [tuple(v) for v in obj["selected_vertices"]],
-                [tuple(e) for e in obj["selected_edges"]],
-                [tuple(t) for t in obj["selected_tris"]],
+                obj["selected_vertices"],
+                obj["selected_edges"],
+                obj["selected_tris"],
             )

src/bonsai/test/bim/module/model/test_array_batch_recut.py

@@ -35,6 +35,7 @@ from unittest.mock import Mock, patch
 
 import bpy
 import ifcopenshell
+import ifcopenshell.api.pset
 import pytest
 
 import bonsai.tool as tool

src/bonsai/test/bim/module/model/test_array_duplicate_batched.py

@@ -37,6 +37,8 @@ from unittest.mock import patch
 
 import bpy
 import ifcopenshell
+import ifcopenshell.api.pset
+import ifcopenshell.util.element
 import pytest
 
 import bonsai.tool as tool

src/bonsai/test/bim/module/model/test_mep_distribution_fit_smoke.py

@@ -146,7 +146,9 @@ def test_fit_flow_segments_with_single_segment_dispatches_obstruction():
         mep.tool.Model, "get_flow_segment_profile", return_value=segment_profile
     ), patch.object(mep.MEPAddObstruction, "_execute", return_value=None) as obstruction, patch.object(
         mep.MEPAddBend, "_execute", return_value=None
-    ) as bend, patch.object(mep.MEPAddTransition, "_execute", return_value=None) as transition:
+    ) as bend, patch.object(
+        mep.MEPAddTransition, "_execute", return_value=None
+    ) as transition:
         mep.FitFlowSegments._execute(op, context=context)
 
     assert obstruction.call_count == 1
@@ -178,7 +180,9 @@ def test_fit_flow_segments_refuses_mixed_pipe_and_duct():
         mep.tool.Model, "get_flow_segment_profile", return_value=profile
     ), patch.object(mep.MEPAddObstruction, "_execute", return_value=None) as obstruction, patch.object(
         mep.MEPAddBend, "_execute", return_value=None
-    ) as bend, patch.object(mep.MEPAddTransition, "_execute", return_value=None) as transition:
+    ) as bend, patch.object(
+        mep.MEPAddTransition, "_execute", return_value=None
+    ) as transition:
         mep.FitFlowSegments._execute(op, context=context)
 
     obstruction.assert_not_called()

src/bonsai/test/bim/module/model/test_mep_segment_edition.py

@@ -173,8 +173,9 @@ def test_gizmo_group_class_wiring(gizmo_cls_name, bl_idname, is_element_predicat
     predicate = getattr(tool.Parametric, is_element_predicate)
     fake_element = Mock()
     fake_element.is_a.return_value = True
-    with patch.object(tool.Parametric, is_element_predicate, side_effect=predicate) as p, patch.object(
-        tool.System, "has_parametric_body", return_value=True
+    with (
+        patch.object(tool.Parametric, is_element_predicate, side_effect=predicate) as p,
+        patch.object(tool.System, "has_parametric_body", return_value=True),
     ):
         cls.is_element_type(fake_element)
     assert p.called, f"{gizmo_cls_name}.is_element_type did not delegate to Parametric.{is_element_predicate}"

src/bonsai/test/bim/module/project/test_autosave.py

@@ -0,0 +1,68 @@
+# 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.
+
+import os
+import time
+from pathlib import Path
+
+import pytest
+
+from bonsai.tool.autosave import AUTOSAVED_SUFFIX, AUTOSAVING_SUFFIX, Autosave
+
+pytestmark = pytest.mark.project
+
+
+class TestAutosavePaths:
+    def test_get_paths_for_ifc_file(self):
+        main_path, autosaving_path, autosaved_path = Autosave.get_paths("/tmp/myfile.ifc")
+        assert main_path == Path("/tmp/myfile.ifc")
+        assert autosaving_path == Path(f"/tmp/myfile{AUTOSAVING_SUFFIX}")
+        assert autosaved_path == Path(f"/tmp/myfile{AUTOSAVED_SUFFIX}")
+
+    def test_get_newer_autosaved_path_when_missing(self, tmp_path):
+        ifc_path = tmp_path / "myfile.ifc"
+        ifc_path.write_text("ifc")
+        assert Autosave.get_newer_autosaved_path(ifc_path) is None
+
+    def test_get_newer_autosaved_path_when_older(self, tmp_path):
+        ifc_path = tmp_path / "myfile.ifc"
+        autosaved_path = tmp_path / f"myfile{AUTOSAVED_SUFFIX}"
+        ifc_path.write_text("ifc")
+        autosaved_path.write_text("autosaved")
+        past = time.time() - 10
+        os.utime(ifc_path, (past, past))
+        os.utime(autosaved_path, (time.time(), time.time()))
+        assert Autosave.get_newer_autosaved_path(ifc_path) == autosaved_path.as_posix()
+
+    def test_get_newer_autosaved_path_when_not_newer(self, tmp_path):
+        ifc_path = tmp_path / "myfile.ifc"
+        autosaved_path = tmp_path / f"myfile{AUTOSAVED_SUFFIX}"
+        ifc_path.write_text("ifc")
+        autosaved_path.write_text("autosaved")
+        now = time.time()
+        os.utime(ifc_path, (now, now))
+        past = now - 10
+        os.utime(autosaved_path, (past, past))
+        assert Autosave.get_newer_autosaved_path(ifc_path) is None
+
+    def test_get_newer_autosaved_path_ignores_non_ifc(self, tmp_path):
+        path = tmp_path / "myfile.ifczip"
+        path.write_text("zip")
+        assert Autosave.get_newer_autosaved_path(path) is None

src/bonsai/test/bim/test_preview_cancel_ops_forward_compat.py

@@ -139,6 +139,5 @@ def test_every_cancel_ops_entry_has_a_real_preview_propertygroup() -> None:
     orphaned = [attr for attr, _op in preview_base.PREVIEW_CANCEL_OPS if attr not in declared_attrs]
     assert not orphaned, (
         "PREVIEW_CANCEL_OPS contains entries whose PointerProperty child no longer "
-        f"exists on {UMBRELLA_CLASS}. Drop the stale tuple(s):\n  "
-        + "\n  ".join(orphaned)
+        f"exists on {UMBRELLA_CLASS}. Drop the stale tuple(s):\n  " + "\n  ".join(orphaned)
     )

src/bonsai/test/modal/test_modal.py

@@ -24,6 +24,7 @@ import time
 
 import bpy
 import ifcopenshell
+import ifcopenshell.util.element
 import pytest
 
 from bonsai import tool as tool

src/bonsai/test/tool/test_model.py

@@ -23,6 +23,7 @@ import bpy
 import ifcopenshell
 import ifcopenshell.api.geometry
 import ifcopenshell.api.material
+import ifcopenshell.api.pset
 import ifcopenshell.api.root
 import ifcopenshell.api.style
 import ifcopenshell.api.type

src/bonsai/test/tool/test_project.py

@@ -501,72 +501,3 @@ class TestGettingLinkedElementGeomSlice:
         obj = cast(bpy.types.Object, obj)
         slice_ = subject.Link.get_linked_element_geom_slice(obj, "aaa")
         assert range(15)[slice_] == range(5)
-
-
-class TestEncodeDecodeLinkFilter:
-    def test_plain_include_round_trip(self):
-        assert subject.encode_link_filter("IfcWall", "") == "IfcWall"
-        assert subject.decode_link_filter("IfcWall") == ("IfcWall", "", False, "")
-
-    def test_empty_filter_encodes_to_none(self):
-        assert subject.encode_link_filter("", "") is None
-        assert subject.decode_link_filter(None) == ("", "", False, "")
-        assert subject.decode_link_filter("") == ("", "", False, "")
-
-    def test_exclude_promotes_to_json(self):
-        encoded = subject.encode_link_filter('IfcElement, group="X"', 'IfcSlab, parent="Y"')
-        assert encoded.startswith("{")
-        assert subject.decode_link_filter(encoded) == ('IfcElement, group="X"', 'IfcSlab, parent="Y"', False, "")
-
-    def test_loaded_promotes_to_json(self):
-        encoded = subject.encode_link_filter("IfcWall", "", loaded=True)
-        assert encoded.startswith("{")
-        assert subject.decode_link_filter(encoded) == ("IfcWall", "", True, "")
-
-    def test_loaded_without_filter(self):
-        encoded = subject.encode_link_filter("", "", loaded=True)
-        assert subject.decode_link_filter(encoded) == ("", "", True, "")
-
-    def test_legacy_non_json_decodes_as_include(self):
-        legacy = 'IfcElement, location="House - Type B"'
-        assert subject.decode_link_filter(legacy) == (legacy, "", False, "")
-
-    def test_malformed_json_decodes_as_include(self):
-        assert subject.decode_link_filter("{not json") == ("{not json", "", False, "")
-
-    def test_display_name_promotes_to_json(self):
-        encoded = subject.encode_link_filter("IfcWall", "", display_name="North Wing")
-        assert encoded.startswith("{")
-        assert subject.decode_link_filter(encoded) == ("IfcWall", "", False, "North Wing")
-
-
-class TestGetLinkCachePaths:
-    def test_empty_filter_keeps_legacy_names(self):
-        blend, json_ = subject.get_link_cache_paths("/x/File A.ifc", "")
-        assert blend.name == "File A.ifc.cache.blend"
-        assert json_.name == "File A.ifc.cache.json"
-
-    def test_include_only_hash_matches_pre_exclude_formula(self):
-        # Existing caches were keyed by md5(query)[:8]; they must stay valid.
-        import hashlib
-
-        blend, _ = subject.get_link_cache_paths("/x/File A.ifc", "IfcWall")
-        expected = hashlib.md5(b"IfcWall").hexdigest()[:8]
-        assert blend.name == f"File A.ifc.cache.{expected}.blend"
-
-    def test_blend_and_json_share_a_suffix(self):
-        blend, json_ = subject.get_link_cache_paths("/x/File A.ifc", "IfcWall", "IfcDoor")
-        assert blend.name.removesuffix("blend") == json_.name.removesuffix("json")
-
-    def test_same_include_different_exclude_do_not_collide(self):
-        # The reason the cache key hashes both strings: same-include links
-        # with different excludes must not serve each other's geometry.
-        a, _ = subject.get_link_cache_paths("/x/f.ifc", "IfcElement", "IfcSlab")
-        b, _ = subject.get_link_cache_paths("/x/f.ifc", "IfcElement", "IfcDoor")
-        c, _ = subject.get_link_cache_paths("/x/f.ifc", "IfcElement", "")
-        assert len({a.name, b.name, c.name}) == 3
-
-    def test_exclude_only_distinct_from_empty_filter(self):
-        a, _ = subject.get_link_cache_paths("/x/f.ifc", "", "IfcDoor")
-        b, _ = subject.get_link_cache_paths("/x/f.ifc", "", "")
-        assert a.name != b.name

src/ifc5d/ifc5d/csv2ifc.py

@@ -57,7 +57,8 @@ class CsvHeader(TypedDict):
 
     # Formula
     Formula: NotRequired[str]
-    #QuantityClass: NotRequired[str]
+    # QuantityClass: NotRequired[str]
+
 
 # Currently we assume that if column is not part of the main header,
 # then it is a cost value category. So here we list any additional column
@@ -97,7 +98,8 @@ class CostItem(TypedDict):
     Query: Union[str, None]
 
     Formula: Union[str, None]
-    #QuantityClass: Union[str, None]
+    # QuantityClass: Union[str, None]
+
 
 class Csv2Ifc:
     # Inputs.
@@ -420,7 +422,7 @@ class Csv2Ifc:
                     products=results,
                     formula=cost_item["Formula"],
                     ifc_class=ifc_quantity_class,
-                    )
+                )
 
         self.create_cost_items(cost_item["children"], cost_item["ifc"])
 

src/ifcconvert/IfcConvert.cpp

@@ -252,6 +252,10 @@ int main(int argc, char** argv) {
 		("stderr-progress", "output progress to stderr stream")
 		("yes,y", "answer 'yes' automatically to possible confirmation queries (e.g. overwriting an existing output file)")
 		("no-progress", "suppress possible progress bar type of prints that use carriage return")
+		("fail-on-error", "return a non-zero exit code when one or more errors were logged during "
+			"geometry conversion (e.g. an element failed to convert). By default IfcConvert exits "
+			"successfully as long as an output file could be written, even if some elements were "
+			"silently dropped. Enable this flag so scripts and CI can detect partial conversions.")
 		("log-format", po::value<std::string>(&log_format), "log format: plain or json")
 		("log-file", new po::typed_value<path_t, char_t>(&log_file), "redirect log output to file");
 
@@ -449,6 +453,7 @@ int main(int argc, char** argv) {
 
 	const bool mmap = vmap.count("mmap") != 0;
 	const bool no_progress = vmap.count("no-progress") != 0;
+	const bool fail_on_error = vmap.count("fail-on-error") != 0;
 	const bool quiet = vmap.count("quiet") != 0;
 	const bool stderr_progress = vmap.count("stderr-progress") != 0;
 
@@ -885,6 +890,7 @@ int main(int argc, char** argv) {
 	}
 
 	if (!serializer->ready()) {
+		logger.Error("SYS", 25, "Unable to open output file '" + IfcUtil::path::to_utf8(output_filename) + "' for writing; check that the directory exists and is writable");
 		IfcUtil::path::delete_file(IfcUtil::path::to_utf8(output_temp_filename));
 		write_log(!quiet);
 		return EXIT_FAILURE;
@@ -1220,6 +1226,11 @@ int main(int argc, char** argv) {
 		successful = false;
 	}
 
+	if (fail_on_error && logger.MaxSeverity() >= Logger::LOG_ERROR) {
+		logger.Error("SYS", 26, "Errors encountered during processing, failing due to --fail-on-error.");
+		successful = false;
+	}
+
 	if (logger.Verbosity() == Logger::LOG_PERF) {
 		logger.PrintPerformanceStats();
 	}

src/ifcgeom/ConversionSettings.h

@@ -361,8 +361,8 @@ namespace ifcopenshell {
 
 			struct CircleSegments : public SettingBase<CircleSegments, int> {
 				static constexpr const char* const name = "circle-segments";
-				static constexpr const char* const description = "Number of segments to approximate full circles in CGAL kernel.";
-				static constexpr int defaultvalue = 16;
+				static constexpr const char* const description = "Number of segments to approximate full circles in the CGAL kernel. When 0 (the default) the segment count is derived from mesher-linear-deflection instead, so curves stay within the deflection tolerance regardless of radius.";
+				static constexpr int defaultvalue = 0;
 			};
 
 			struct CgalSmoothAngleDegrees : public SettingBase<CgalSmoothAngleDegrees, double> {

src/ifcgeom/kernels/cgal/CgalKernel.cpp

@@ -391,6 +391,11 @@ namespace {
 		}
 	};
 
+	// Representative radius used to size the polygonal approximation of a conic.
+	// For an ellipse the larger semi-axis is the conservative choice.
+	inline double conic_radius(const taxonomy::circle::ptr& c) { return c->radius; }
+	inline double conic_radius(const taxonomy::ellipse::ptr& e) { return e->radius > e->radius2 ? e->radius : e->radius2; }
+
 	struct cgal_curve_creation_visitor {
 		Settings& settings_;
 		parameter_range param;
@@ -425,7 +430,36 @@ namespace {
 			if (b <= a) {
 				b += 2 * M_PI;
 			}
-			int num_segments = (int)std::ceil(std::fabs(a - b) / (2 * M_PI) * settings_.get<settings::CircleSegments>().get());
+			const double span = std::fabs(a - b);
+			// CircleSegments controls how conics (circles, ellipses, arcs) are approximated
+			// in the CGAL kernel. Two modes, one or the other:
+			//  - CircleSegments == 0 (the default): the segment count is derived from
+			//    MesherLinearDeflection, so the chord deviation stays within the mesher's
+			//    linear deflection regardless of radius. This matches the deflection based
+			//    meshing the OpenCascade kernel already does and fixes issue #8051, where
+			//    large radius arcs (curved curtain wall mullions) collapsed to straight chords
+			//    because a fixed segment count is radius agnostic.
+			//  - CircleSegments > 0: it is used directly as the number of segments for a full
+			//    circle, giving deterministic, radius independent output.
+			int num_segments;
+			const int circle_segments = settings_.get<settings::CircleSegments>().get();
+			if (circle_segments > 0) {
+				num_segments = (int)std::ceil(span / (2 * M_PI) * circle_segments);
+			} else {
+				const double radius = conic_radius(t);
+				const double deflection = settings_.get<settings::MesherLinearDeflection>().get();
+				if (deflection > 0. && radius > deflection) {
+					const double max_segment_angle = 2.0 * std::acos(1.0 - deflection / radius);
+					num_segments = (int)std::ceil(span / max_segment_angle);
+				} else {
+					// Radius within the deflection tolerance (or no deflection set): a chord per
+					// quarter turn already keeps the deviation within tolerance.
+					num_segments = (int)std::ceil(span / (M_PI / 2.));
+				}
+			}
+			if (num_segments < 1) {
+				num_segments = 1;
+			}
 			double du = (b - a) / num_segments;
 			taxonomy::point3 P;
 			// @nb for loop is not inclusive of the both end points

src/ifcgeom/kernels/opencascade/face.cpp

@@ -31,6 +31,7 @@
 #include <ShapeFix_Shape.hxx>
 #include <ShapeFix_ShapeTolerance.hxx>
 #include <BRep_Tool.hxx>
+#include <BRepExtrema_DistShapeShape.hxx>
 
 #include <Standard_Macro.hxx>
 #include <TopoDS_Shape.hxx>
@@ -356,6 +357,27 @@ bool OpenCascadeKernel::convert(const taxonomy::face::ptr face, TopoDS_Shape& re
 		return false;
 	}
 
+	// #527: A face whose inner boundary intersects the outer boundary (or
+	// another inner boundary) is invalid per the schema. Open Cascade heals or
+	// drops such a face silently, so the intended hole is lost with no
+	// diagnostic. The distance between two non-intersecting loops is strictly
+	// positive; a distance at (or below) the modelling precision means the
+	// boundaries touch or cross. Emit a clear warning so the invalid input is
+	// not silently lost. wires() is ordered outer-first, inner-bounds after.
+	if (fd.wires().size() > 1) {
+		const auto& fwires = fd.wires();
+		bool reported = false;
+		for (size_t i = 1; i < fwires.size() && !reported; ++i) {
+			for (size_t j = 0; j < i && !reported; ++j) {
+				BRepExtrema_DistShapeShape dss(fwires[i], fwires[j]);
+				if (dss.IsDone() && dss.Value() < precision_) {
+					logger().Warning("GEO", 402, "Face inner boundary intersects another face boundary", face->instance);
+					reported = true;
+				}
+			}
+		}
+	}
+
 	if (fd.surface().IsNull()) {
 		// Use the first wire to find a plane manually for polygonal wires
 		const TopoDS_Wire& wire = fd.wires().front();

src/ifcgeom/mapping/IfcAsymmetricIShapeProfileDef.cpp

@@ -0,0 +1,93 @@
+// 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 "mapping.h"
+#define mapping POSTFIX_SCHEMA(mapping)
+using namespace ifcopenshell::geometry;
+
+#include "../profile_helper.h"
+
+// In IFC2X3 IfcAsymmetricIShapeProfileDef is a subtype of IfcIShapeProfileDef and is
+// therefore dispatched (and handled) by the IfcIShapeProfileDef mapping. From IFC4
+// onwards it is a standalone subtype of IfcParameterizedProfileDef with its own
+// Bottom*/Top* attributes, so nothing mapped it and the extrusion came out empty.
+// The presence of the standalone BottomFlangeWidth attribute is the discriminator:
+// it is only defined in the schemas where the type is standalone (IFC4 / IFC4X3).
+#ifdef SCHEMA_IfcAsymmetricIShapeProfileDef_HAS_BottomFlangeWidth
+
+taxonomy::ptr mapping::map_impl(const IfcSchema::IfcAsymmetricIShapeProfileDef* inst) {
+	// Bottom flange (half width), overall depth (half), web (half thickness).
+	const double xb = inst->BottomFlangeWidth() / 2.0 * length_unit_;
+	const double xt = inst->TopFlangeWidth() / 2.0 * length_unit_;
+	const double y = inst->OverallDepth() / 2.0 * length_unit_;
+	const double d1 = inst->WebThickness() / 2.0 * length_unit_;
+
+	// Bottom flange thickness; top flange thickness defaults to the bottom one.
+	const double ftb = inst->BottomFlangeThickness() * length_unit_;
+	const double ftt = inst->TopFlangeThickness().get_value_or(inst->BottomFlangeThickness()) * length_unit_;
+
+	// Optional fillet radii (web/flange transition) and flange edge radii.
+	const double fb = inst->BottomFlangeFilletRadius().get_value_or(0.) * length_unit_;
+	const double ft_top = inst->TopFlangeFilletRadius().get_value_or(0.) * length_unit_;
+	const double feb = inst->BottomFlangeEdgeRadius().get_value_or(0.) * length_unit_;
+	const double fet = inst->TopFlangeEdgeRadius().get_value_or(0.) * length_unit_;
+
+	// Optional flange slopes: the inner edge of the flange rises towards the web.
+	const double bottomSlope = inst->BottomFlangeSlope().get_value_or(0.) * angle_unit_;
+	const double topSlope = inst->TopFlangeSlope().get_value_or(0.) * angle_unit_;
+	const double dyb = (xb - d1) * tan(bottomSlope);
+	const double dyt = (xt - d1) * tan(topSlope);
+
+	const double tol = settings_.get<settings::Precision>().get();
+
+	if (xb < tol || xt < tol || y < tol || d1 < tol || ftb < tol || ftt < tol) {
+		logger_.Message(Logger::LOG_NOTICE, "GEO", 264, "Skipping zero sized profile:", inst);
+		return nullptr;
+	}
+
+	taxonomy::matrix4::ptr m4;
+	bool has_position = true;
+#ifdef SCHEMA_IfcParameterizedProfileDef_Position_IS_OPTIONAL
+	has_position = !!inst->Position();
+#endif
+	if (has_position) {
+		m4 = taxonomy::cast<taxonomy::matrix4>(map(inst->Position()));
+	}
+
+	// Twelve corner points, running counter-clockwise from the bottom-left, with the
+	// bottom flange (xb) possibly wider than the top flange (xt). Fillet/edge radii are
+	// attached to the corner they round, matching the symmetric IfcIShapeProfileDef.
+	return profile_helper(m4, {
+		{{-xb,-y}},
+		{{xb,-y}},
+		{{xb,-y + ftb}, {feb}},
+		{{d1,-y + ftb + dyb},{fb} },
+		{{d1,y - ftt - dyt},{ft_top} },
+		{{xt,y - ftt}, {fet}},
+		{{xt,y}},
+		{{-xt,y}},
+		{{-xt,y - ftt}, {fet}},
+		{{-d1,y - ftt - dyt},{ft_top} },
+		{{-d1,-y + ftb + dyb},{fb} },
+		{{-xb,-y + ftb}, {feb}}
+	});
+}
+
+#endif

src/ifcgeom/mapping/IfcPolygonalFaceSet.cpp

@@ -39,8 +39,25 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcPolygonalFaceSet* inst) {
 
 	int max_index = (int)points.size();
 
+	// When the optional PnIndex is present, CoordIndex values do not index into
+	// CoordList directly but into PnIndex, which in turn remaps to CoordList.
+	// Both index levels are 1-based per the IFC specification.
+	auto pn_index = inst->PnIndex();
+	auto resolve = [&](int idx) -> const taxonomy::point3::ptr& {
+		if (pn_index) {
+			if (idx < 1 || idx > (int)pn_index->size()) {
+				throw IfcParse::IfcException("IfcPolygonalFaceSet PnIndex out of bounds for index " + boost::lexical_cast<std::string>(idx));
+			}
+			idx = (*pn_index)[idx - 1];
+		}
+		if (idx < 1 || idx > max_index) {
+			throw IfcParse::IfcException("IfcPolygonalFaceSet index out of bounds for index " + boost::lexical_cast<std::string>(idx));
+		}
+		return points[idx - 1];
+	};
+
 	auto shell = taxonomy::make<taxonomy::shell>();
-	
+
 	for (auto& f : *polygonal_faces) {
 		auto fa = taxonomy::make<taxonomy::face>();
 		shell->children.push_back(fa);
@@ -52,17 +69,14 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcPolygonalFaceSet* inst) {
 			auto indices = f->CoordIndex();
 			taxonomy::point3::ptr previous;
 			for (std::vector<int>::const_iterator jt = indices.begin(); jt != indices.end(); ++jt) {
-				if (*jt < 1 || *jt > max_index) {
-					throw IfcParse::IfcException("IfcPolygonalFaceSet index out of bounds for index " + boost::lexical_cast<std::string>(*jt));
-				}
-				auto current = points[(*jt) - 1];
+				auto current = resolve(*jt);
 				if (jt != indices.begin()) {
 					loop->children.push_back(taxonomy::make<taxonomy::edge>(previous, current));
 				}
 				previous = current;
 			}
 			if (!indices.empty()) {
-				auto current = points[indices.front() - 1];
+				auto current = resolve(indices.front());
 				loop->children.push_back(taxonomy::make<taxonomy::edge>(previous, current));
 			}
 		}
@@ -77,17 +91,14 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcPolygonalFaceSet* inst) {
 					loop->external = false;
 
 					for (std::vector<int>::const_iterator jt = li.begin(); jt != li.end(); ++jt) {
-						if (*jt < 1 || *jt > max_index) {
-							throw IfcParse::IfcException("IfcPolygonalFaceSet index out of bounds for index " + boost::lexical_cast<std::string>(*jt));
-						}
-						auto current = points[(*jt) - 1];
+						auto current = resolve(*jt);
 						if (jt != li.begin()) {
 							loop->children.push_back(taxonomy::make<taxonomy::edge>(previous, current));
 						}
 						previous = current;
 					}
 					if (!li.empty()) {
-						auto current = points[li.front() - 1];
+						auto current = resolve(li.front());
 						loop->children.push_back(taxonomy::make<taxonomy::edge>(previous, current));
 					}
 				}

src/ifcgeom/mapping/IfcTriangulatedFaceSet.cpp

@@ -39,6 +39,23 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcTriangulatedFaceSet* inst) {
 
 	int max_index = (int)points.size();
 
+	// When the optional PnIndex is present, CoordIndex values do not index into
+	// CoordList directly but into PnIndex, which in turn remaps to CoordList.
+	// Both index levels are 1-based per the IFC specification.
+	auto pn_index = inst->PnIndex();
+	auto resolve = [&](int idx) -> const taxonomy::point3::ptr& {
+		if (pn_index) {
+			if (idx < 1 || idx > (int)pn_index->size()) {
+				throw IfcParse::IfcException("IfcTriangulatedFaceSet PnIndex out of bounds for index " + boost::lexical_cast<std::string>(idx));
+			}
+			idx = (*pn_index)[idx - 1];
+		}
+		if (idx < 1 || idx > max_index) {
+			throw IfcParse::IfcException("IfcTriangulatedFaceSet index out of bounds for index " + boost::lexical_cast<std::string>(idx));
+		}
+		return points[idx - 1];
+	};
+
 	auto shell = taxonomy::make<taxonomy::shell>();
 
 	for (auto& indices : indices_list) {
@@ -51,10 +68,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcTriangulatedFaceSet* inst) {
 			loop->external = true;
 			taxonomy::point3::ptr first, previous;
 			for (std::vector<int>::const_iterator jt = indices.begin(); jt != indices.end(); ++jt) {
-				if (*jt < 1 || *jt > max_index) {
-					throw IfcParse::IfcException("IfcTriangulatedFaceSet index out of bounds for index " + boost::lexical_cast<std::string>(*jt));
-				}
-				const taxonomy::point3::ptr& current = points[(*jt) - 1];
+				const taxonomy::point3::ptr& current = resolve(*jt);
 				if (jt == indices.begin()) {
 					first = current;
 				} else {

src/ifcgeom/mapping/mapping.i

@@ -89,7 +89,11 @@ BIND(IfcRectangleHollowProfileDef);
 BIND(IfcRectangleProfileDef);
 BIND(IfcTrapeziumProfileDef);
 BIND(IfcCShapeProfileDef);
-// IfcAsymmetricIShapeProfileDef included
+// In IFC2X3 IfcAsymmetricIShapeProfileDef is a subtype of IfcIShapeProfileDef and is
+// mapped by it; from IFC4 onwards it is a standalone type and needs its own binding.
+#ifdef SCHEMA_IfcAsymmetricIShapeProfileDef_HAS_BottomFlangeWidth
+BIND(IfcAsymmetricIShapeProfileDef);
+#endif
 BIND(IfcIShapeProfileDef);
 BIND(IfcLShapeProfileDef);
 BIND(IfcTShapeProfileDef);

src/ifcopenshell-python/docs/ifcconvert/usage.rst

@@ -311,8 +311,12 @@ CLI Manual
                                             output.
       --force-space-transparency arg        Overrides transparency of spaces in 
                                             geometry output.
-      --circle-segments arg (= 16)          Number of segments to approximate full 
-                                            circles in CGAL kernel.
+      --circle-segments arg (= 0)           Number of segments to approximate full
+                                            circles in the CGAL kernel. When 0 (the
+                                            default) the segment count is derived from
+                                            mesher-linear-deflection instead, so curves
+                                            stay within the deflection tolerance
+                                            regardless of radius.
       --cgal-smooth-angle-degrees arg (= -1)
                                             Angle in degrees under which adjacent 
                                             facets will have averaged vertex 

src/ifcopenshell-python/docs/ifcopenshell/geometry_settings.rst

@@ -228,10 +228,10 @@ circle-segments
 +------+-----------------------+---------+
 | Type | IfcConvert Option     | Default |
 +======+=======================+=========+
-| INT  | ``--circle-segments`` | 16      |
+| INT  | ``--circle-segments`` | 0       |
 +------+-----------------------+---------+
 
-Number of segments to approximate full circles in CGAL kernel.
+Number of segments to approximate full circles in the CGAL kernel. When 0 (the default) the segment count is derived from mesher-linear-deflection instead, so curves stay within the deflection tolerance regardless of radius.
 
 context-identifiers
 ^^^^^^^^^^^^^^^^^^^

src/ifcopenshell-python/ifcopenshell/__init__.py

@@ -231,7 +231,7 @@ def open(
         kwargs = {"mmap": mmap}
         if logger is not None:
             kwargs["logger"] = logger
-        f = ifcopenshell_wrapper.open(str(path.absolute()), **kwargs)  # ty: ignore[unknown-argument]
+        f = ifcopenshell_wrapper.open(str(path.absolute()), **kwargs)
     else:
         f = ifcopenshell_wrapper.open(str(path.absolute()), False, *((logger,) if logger is not None else ()))
     return file(f)

src/ifcopenshell-python/ifcopenshell/api/alignment/__init__.py

@@ -49,6 +49,7 @@ Future versions of this API may support:
 
 from ._get_segment_start_point_label import register_referent_name_callback
 from .add_stationing_referent import add_stationing_referent
+from .add_positioning_referent import add_positioning_referent
 from .add_vertical_layout import add_vertical_layout
 from .add_zero_length_segment import add_zero_length_segment
 from .create import create
@@ -94,6 +95,7 @@ from .util import *
 
 __all__ = [
     "add_stationing_referent",
+    "add_positioning_referent",
     "add_vertical_layout",
     "add_zero_length_segment",
     "create",

src/ifcopenshell-python/ifcopenshell/api/alignment/_add_segment_to_curve.py

@@ -22,8 +22,6 @@ import numpy as np
 import ifcopenshell
 import ifcopenshell.api.alignment
 import ifcopenshell.geom
-import ifcopenshell.ifcopenshell_wrapper as ifcopenshell_wrapper
-import ifcopenshell.util.unit
 from ifcopenshell import entity_instance
 from ifcopenshell.api.alignment._get_segment_endpoint import _get_segment_endpoint
 from ifcopenshell.api.alignment._update_zero_length_segment_placement import _update_zero_length_segment_placement

src/ifcopenshell-python/ifcopenshell/api/alignment/_add_segment_to_layout.py

@@ -22,28 +22,11 @@ import numpy as np
 
 import ifcopenshell
 import ifcopenshell.api.alignment
-from ifcopenshell.api.alignment import _map_alignment_cant_segment
 from ifcopenshell.api.alignment._update_zero_length_segment_placement import _update_zero_length_segment_placement
 import ifcopenshell.api.nest
-import ifcopenshell.api.pset
-import ifcopenshell.geom
-import ifcopenshell.util.alignment
-import ifcopenshell.util.unit
-from ifcopenshell import entity_instance, ifcopenshell_wrapper
+from ifcopenshell import entity_instance
 from ifcopenshell.api.alignment._add_segment_to_curve import _add_segment_to_curve
 from ifcopenshell.api.alignment._get_segment_endpoint import _get_segment_endpoint
-from ifcopenshell.api.alignment._get_segment_start_point_label import (
-    _get_segment_start_point_label,
-)
-from ifcopenshell.api.alignment._map_alignment_cant_segment import (
-    _map_alignment_cant_segment,
-)
-from ifcopenshell.api.alignment._map_alignment_horizontal_segment import (
-    _map_alignment_horizontal_segment,
-)
-from ifcopenshell.api.alignment._map_alignment_vertical_segment import (
-    _map_alignment_vertical_segment,
-)
 
 
 def _add_segment_to_layout(

src/ifcopenshell-python/ifcopenshell/api/alignment/_add_zero_length_segment.py

@@ -18,11 +18,7 @@
 
 import ifcopenshell
 import ifcopenshell.api.alignment
-import ifcopenshell.util.alignment
 from ifcopenshell import entity_instance
-from ifcopenshell.api.alignment._get_segment_start_point_label import (
-    _get_segment_start_point_label,
-)
 
 
 def _add_zero_length_segment(file: ifcopenshell.file, layout: entity_instance) -> None:

src/ifcopenshell-python/ifcopenshell/api/alignment/_get_segment_endpoint.py

@@ -18,6 +18,7 @@
 
 
 import ifcopenshell.api.alignment
+import ifcopenshell.geom
 from ifcopenshell import entity_instance, ifcopenshell_wrapper
 from ifcopenshell.api.alignment._map_alignment_segment import _map_alignment_segment
 from typing import Union

src/ifcopenshell-python/ifcopenshell/api/alignment/add_positioning_referent.py

@@ -0,0 +1,113 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 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
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.api.alignment
+from ifcopenshell.api.alignment.update_fallback_position import update_fallback_position
+import ifcopenshell.api.pset
+import ifcopenshell.guid
+from ifcopenshell import entity_instance
+
+
+def add_positioning_referent(
+    file: ifcopenshell.file,
+    name: str,
+    alignment: entity_instance,
+    distance_along: float,
+    station: float,
+    positioned_product: entity_instance,
+) -> entity_instance:
+    """
+    Semantically defines the position of a product along an alignment by adding an IfcReferent to the alignment that defines the stationing system.
+
+    :param alignment: the alignment to receive the referent
+    :param distance_along: distance along the alignment basis curve
+    :param station: station value
+    :param name: name to assign to IfcReferent.Name, typically a stringized version of the station value
+    :param positioned_product: the product whose position is informed by the referent
+    :return: referent
+
+    Example:
+
+    .. code:: python
+
+        alignment = model.by_type("IfcAlignment")[0]
+        pier = model.by_type("IfcBridgePart")[0]
+        ifcopenshell.api.alignment.add_positioning_referent(model,name="Pier 1 Sta 1+00",alignment=alignment,distance_along=0.0,station=100.0,positioned_product=pier)
+    """
+
+    curve = ifcopenshell.api.alignment.get_curve(alignment)
+
+    object_placement = None
+    representation = None
+    if curve and curve.is_a("IfcCompositeCurve") and 0 < len(curve.Segments):
+        object_placement = file.createIfcLinearPlacement(
+            RelativePlacement=file.createIfcAxis2PlacementLinear(
+                Location=file.createIfcPointByDistanceExpression(
+                    DistanceAlong=file.createIfcLengthMeasure(distance_along),
+                    OffsetLateral=None,
+                    OffsetVertical=None,
+                    OffsetLongitudinal=None,
+                    BasisCurve=curve,
+                )
+            ),
+        )
+
+        update_fallback_position(file, object_placement)
+    else:
+        object_placement = file.createIfcLocalPlacement(
+            PlacementRelTo=None,
+            RelativePlacement=file.createIfcAxis2Placement2D(
+                Location=file.createIfcCartesianPoint(alignment.ObjectPlacement.RelativePlacement.Location.Coordinates)
+            ),
+        )
+
+    # this commented out code is what you would do to add a geometric representation of the referent
+    # the example is a circle. a better way would be to pass a representation into the function
+    #    representation = file.create_entity(
+    #        name="IfcCircle",
+    #        position=file.createIfcAxis2Placement2D(Location=file.createIfcCartesianPoint(Coordinates=(0.0, 0.0)),
+    #        radius=1.0)
+    #    )
+
+    # create referent for the station
+    referent = file.createIfcReferent(
+        GlobalId=ifcopenshell.guid.new(),
+        OwnerHistory=None,
+        Name=name,
+        Description=None,
+        ObjectType=None,
+        ObjectPlacement=object_placement,
+        Representation=representation,
+        PredefinedType="POSITION",
+    )
+    pset_stationing = ifcopenshell.api.pset.add_pset(file, product=referent, name="Pset_Stationing")
+    ifcopenshell.api.pset.edit_pset(file, pset=pset_stationing, properties={"Station": station})
+
+    if len(referent.Positions) == 0:
+        rel_positions = file.createIfcRelPositions(
+            GlobalId=ifcopenshell.guid.new(),
+            RelatingPositioningElement=referent,
+            RelatedProducts=[
+                positioned_product,
+            ],
+        )
+    else:
+        referent.Positions[0].RelatedProducts += (positioned_product,)
+
+    return referent

src/ifcopenshell-python/ifcopenshell/api/alignment/add_stationing_referent.py

@@ -16,35 +16,35 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
-import numpy as np
+from typing import Optional
 
 import ifcopenshell
 import ifcopenshell.api.alignment
 from ifcopenshell.api.alignment.update_fallback_position import update_fallback_position
 import ifcopenshell.api.pset
-import ifcopenshell.geom
 import ifcopenshell.guid
 import ifcopenshell.util.element
-import ifcopenshell.util.unit
-from ifcopenshell import entity_instance, ifcopenshell_wrapper
+from ifcopenshell import entity_instance
 
 
 def add_stationing_referent(
     file: ifcopenshell.file,
+    name: str,
     alignment: entity_instance,
     distance_along: float,
     station: float,
-    name: str,
-    positioned_product: entity_instance,
+    incoming_station: Optional[float] = None,
+    on_basis_curve: Optional[bool] = None,
 ) -> entity_instance:
     """
-    Adds an IfcReferent to the alignment with the Pset_Stationing property set.
+    Adds an IfcReferent to the alignment that defines the stationing system.
 
+    :param name: name to assign to IfcReferent.Name, typically a stringized version of the station value
     :param alignment: the alignment to receive the referent
     :param distance_along: distance along the alignment basis curve
     :param station: station value
-    :param name: name to assign to IfcReferent.Name, typically a stringized version of the station value
-    :param positioned_product: the product whose position is informed by the referent
+    :param incoming_station: station value of the incoming segment, only set to specify a station equation
+    :param on_basis_curve: whether the referent is positioned on the basis curve or the alignment curve, if None the function will default to the basis curve
     :return: referent
 
     Example:
@@ -52,14 +52,21 @@ def add_stationing_referent(
     .. code:: python
 
         alignment = model.by_type("IfcAlignment")[0]
-        ifcopenshell.api.alignment.add_stationing_referent(model,alignment=alignment,distance_along=0.0,station=100.0)
+        ifcopenshell.api.alignment.add_stationing_referent(model,name="1+00.0",alignment=alignment,distance_along=0.0,station=100.0)
     """
 
-    basis_curve = ifcopenshell.api.alignment.get_basis_curve(alignment)
+    if on_basis_curve is None:
+        on_basis_curve = True
+
+    curve = (
+        ifcopenshell.api.alignment.get_basis_curve(alignment)
+        if on_basis_curve
+        else ifcopenshell.api.alignment.get_curve(alignment)
+    )
 
     object_placement = None
     representation = None
-    if basis_curve and basis_curve.is_a("IfcCompositeCurve") and 0 < len(basis_curve.Segments):
+    if curve and curve.is_a("IfcCompositeCurve") and 0 < len(curve.Segments):
         object_placement = file.createIfcLinearPlacement(
             RelativePlacement=file.createIfcAxis2PlacementLinear(
                 Location=file.createIfcPointByDistanceExpression(
@@ -67,7 +74,7 @@ def add_stationing_referent(
                     OffsetLateral=None,
                     OffsetVertical=None,
                     OffsetLongitudinal=None,
-                    BasisCurve=basis_curve,
+                    BasisCurve=curve,
                 )
             ),
         )
@@ -100,8 +107,12 @@ def add_stationing_referent(
         Representation=representation,
         PredefinedType="STATION",
     )
+    properties = {"Station": station}
+    if incoming_station is not None:
+        properties["IncomingStation"] = incoming_station
+
     pset_stationing = ifcopenshell.api.pset.add_pset(file, product=referent, name="Pset_Stationing")
-    ifcopenshell.api.pset.edit_pset(file, pset=pset_stationing, properties={"Station": station})
+    ifcopenshell.api.pset.edit_pset(file, pset=pset_stationing, properties=properties)
 
     nest = ifcopenshell.api.alignment.get_referent_nest(file, alignment)
     if nest is None:
@@ -115,15 +126,4 @@ def add_stationing_referent(
         nest.RelatedObjects, key=lambda x: ifcopenshell.util.element.get_pset(x, name="Pset_Stationing", prop="Station")
     )
 
-    if len(referent.Positions) == 0:
-        rel_positions = file.createIfcRelPositions(
-            GlobalId=ifcopenshell.guid.new(),
-            RelatingPositioningElement=referent,
-            RelatedProducts=[
-                positioned_product,
-            ],
-        )
-    else:
-        referent.Positions[0].RelatedProducts += (positioned_product,)
-
     return referent

src/ifcopenshell-python/ifcopenshell/api/alignment/add_vertical_layout.py

@@ -51,18 +51,6 @@ def _move_vertical_layout_to_child_alignment(
     # aggregate the child alignment to the parent alignment
     ifcopenshell.api.aggregate.assign_object(file, products=[child_alignment], relating_object=parent_alignment)
 
-    # move all referents positioning segments of the vertical layout to the referent nest of the child alignment
-    child_referent_nest = ifcopenshell.api.alignment.get_referent_nest(file, child_alignment)
-    parent_referent_nest = ifcopenshell.api.alignment.get_referent_nest(file, parent_alignment)
-    for referent in parent_referent_nest.RelatedObjects:
-        for product in referent.Positions[0].RelatedProducts:
-            if product.is_a("IfcAlignmentSegment") and product.Nests[0].RelatingObject == vertical_layout:
-                # ifcopenshell.api.nest.change_nest(file,referent,child_alignment) - this doesn't work because referent is assigned to child_alignment.IsNestedBy[0].RelatedObjects
-                # and it needs to be assigned to child_alignment.IsNestedBy[1].RelatedObjects
-                # move the referent manually - unassign it and add it to the child alignment's referent nest
-                ifcopenshell.api.nest.unassign_object(file, [referent])
-                child_referent_nest.RelatedObjects += (referent,)
-
     # if the parent alignment has a representation, move the Axis/Curve3D represention to the child alignment
     base_curve = ifcopenshell.api.alignment.get_basis_curve(parent_alignment)
     if base_curve:

src/ifcopenshell-python/ifcopenshell/api/alignment/add_zero_length_segment.py

@@ -23,18 +23,8 @@ import ifcopenshell.api.alignment
 from ifcopenshell.api.alignment._get_segment_endpoint import _get_segment_endpoint
 from ifcopenshell.api.alignment._update_zero_length_segment_placement import _update_zero_length_segment_placement
 import ifcopenshell.api.nest
-import ifcopenshell.ifcopenshell_wrapper as wrapper
 import ifcopenshell.util.unit
 from ifcopenshell import entity_instance
-from ifcopenshell.api.alignment._get_segment_start_point_label import (
-    _get_segment_start_point_label,
-)
-from ifcopenshell.api.alignment._map_alignment_horizontal_segment import (
-    _map_alignment_horizontal_segment,
-)
-from ifcopenshell.api.alignment._map_alignment_vertical_segment import (
-    _map_alignment_vertical_segment,
-)
 from ifcopenshell.api.alignment._update_curve_segment_transition_code import (
     _update_curve_segment_transition_code,
 )

src/ifcopenshell-python/ifcopenshell/api/alignment/create.py

@@ -87,9 +87,7 @@ def create(
         _create_geometric_representation(file, alignment)
 
     referent_name = ifcopenshell.util.alignment.station_as_string(file, start_station)
-    referent = ifcopenshell.api.alignment.add_stationing_referent(
-        file, alignment, 0.0, start_station, referent_name, alignment
-    )
+    referent = ifcopenshell.api.alignment.add_stationing_referent(file, referent_name, alignment, 0.0, start_station)
 
     for layout in alignment_layouts:
         _add_zero_length_segment(file, layout)

src/ifcopenshell-python/ifcopenshell/api/alignment/create_as_polyline.py

@@ -141,7 +141,7 @@ def create_as_polyline(
 
     # define stationing
     name = ifcopenshell.util.alignment.station_as_string(file, start_station)
-    referent = ifcopenshell.api.alignment.add_stationing_referent(file, alignment, 0.0, start_station, name, alignment)
+    referent = ifcopenshell.api.alignment.add_stationing_referent(file, name, alignment, 0.0, start_station)
 
     # IFC 4.1.4.1.1 Alignment Aggregation To Project
     project = file.by_type("IfcProject")[0]

src/ifcopenshell-python/ifcopenshell/api/alignment/create_layout_segment.py

@@ -21,9 +21,7 @@ from typing import Union
 import numpy as np
 
 import ifcopenshell
-import ifcopenshell.api.alignment
-import ifcopenshell.geom
-from ifcopenshell import entity_instance, ifcopenshell_wrapper
+from ifcopenshell import entity_instance
 from ifcopenshell.api.alignment._add_segment_to_layout import _add_segment_to_layout
 
 

src/ifcopenshell-python/ifcopenshell/api/alignment/distance_along_from_station.py

@@ -16,23 +16,47 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
+from typing import Optional
+
 import ifcopenshell
 import ifcopenshell.api.alignment
+import ifcopenshell.util.element
 from ifcopenshell import entity_instance
 
 
-def distance_along_from_station(file: ifcopenshell.file, alignment: entity_instance, station: float) -> float:
+def _distance_along_of_referent(referent: entity_instance) -> float:
+    placement = referent.ObjectPlacement
+    if placement.is_a("IfcLinearPlacement"):
+        return placement.RelativePlacement.Location.DistanceAlong.wrappedValue
+    # IfcLocalPlacement fallback (e.g. semantic-only alignment, or the placement could not yet
+    # be expressed relative to a basis curve) carries no DistanceAlong; it is only ever used for
+    # the starting referent, at distance 0.0.
+    return 0.0
+
+
+def distance_along_from_station(file: ifcopenshell.file, alignment: entity_instance, station: float) -> Optional[float]:
     """
     Given a station, returns the distance along the horizontal alignment.
 
     If the alignment does not have stationing defined with an IfcReferent, the start of the alignment is assumed
     to be at station 0.0. That is, the station is the distance along.
 
-    .. note:: The current implementation does not account for station equations and assumes stationing is increasing along the alignment.
+    Station equations (where Pset_Stationing.IncomingStation is set on a referent) are taken into account.
+    For each STATION referent nested to the alignment, DistanceAlong (D) and the outgoing station (S, i.e.
+    Pset_Stationing.Station) are read off, sorted by DistanceAlong. The requested station is located within
+    the segment defined by the last referent whose outgoing station is less than or equal to it, and the
+    distance along is computed as D + (station - S) for that referent.
+
+    If the station falls within a gap introduced by a forward (gap) station equation - that is, it was skipped
+    over by the equation - there is no distance along that corresponds to it, and None is returned.
+
+    Note that an overlap (backward) station equation causes a range of stations to correspond to two distinct
+    distances along the alignment, one on either side of the equation. This implementation returns the distance
+    along in the segment following the equation (i.e. the outgoing side).
 
     :param alignment: the alignment
     :param station: station value
-    :return: distance along the horizontal alignment
+    :return: distance along the horizontal alignment, or None if the station falls inside a station equation gap
 
     Example:
 
@@ -43,6 +67,36 @@ def distance_along_from_station(file: ifcopenshell.file, alignment: entity_insta
         print(dist_along) # 100.00
     """
 
-    start_station = ifcopenshell.api.alignment.get_alignment_start_station(file, alignment)
-    dist_along = station - start_station
-    return dist_along
+    referent_nest = ifcopenshell.api.alignment.get_referent_nest(file, alignment)
+    if referent_nest is None:
+        start_station = ifcopenshell.api.alignment.get_alignment_start_station(file, alignment)
+        return station - start_station
+
+    stations = [
+        (
+            _distance_along_of_referent(referent),
+            ifcopenshell.util.element.get_pset(referent, name="Pset_Stationing", prop="Station"),
+        )
+        for referent in referent_nest.RelatedObjects
+    ]
+    stations.sort(key=lambda entry: entry[0])
+
+    index = None
+    for i, (distance_along, outgoing_station) in enumerate(stations):
+        if outgoing_station <= station:
+            index = i
+
+    if index is None:
+        # station precedes the alignment's starting station; extrapolate from the first referent
+        distance_along, outgoing_station = stations[0]
+        return distance_along + (station - outgoing_station)
+
+    distance_along, outgoing_station = stations[index]
+
+    if index + 1 < len(stations):
+        next_distance_along, _ = stations[index + 1]
+        if station - outgoing_station > next_distance_along - distance_along:
+            # the station was skipped over by a forward (gap) station equation
+            return None
+
+    return distance_along + (station - outgoing_station)

src/ifcopenshell-python/ifcopenshell/api/alignment/get_curve_segment.py

@@ -16,7 +16,6 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
-from collections.abc import Sequence
 
 from ifcopenshell import entity_instance
 

src/ifcopenshell-python/ifcopenshell/api/alignment/update_end_point.py

@@ -19,6 +19,7 @@
 import numpy as np
 
 import ifcopenshell
+import ifcopenshell.api.alignment
 import ifcopenshell.util.placement
 from ifcopenshell import entity_instance
 

src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py

@@ -117,7 +117,7 @@ def assign_cost_item_quantity(
         "products": products or [],
         "prop_name": prop_name,
         "formula": formula,
-        "ifc_class" : ifc_class
+        "ifc_class": ifc_class,
     }
     return usecase.execute()
 
@@ -134,7 +134,7 @@ class Usecase:
                 continue
             self.assign_cost_control(related_object=product, cost_item=self.settings["cost_item"])
             if self.settings["formula"]:
-                tree = ast.parse(self.settings["formula"], mode = "eval")
+                tree = ast.parse(self.settings["formula"], mode="eval")
                 collector = VariableExtractor()
                 collector.visit(tree)
                 variables = collector.variables
@@ -144,10 +144,10 @@ class Usecase:
                     value = getter(product, variable)
 
                 if value is None:
-                        print(
-                            f"WARNING: Variable '{variable}' in product '{product.Name}' "
-                            f"is missing (None). Check Pset/Qset or property name."
-                        )
+                    print(
+                        f"WARNING: Variable '{variable}' in product '{product.Name}' "
+                        f"is missing (None). Check Pset/Qset or property name."
+                    )
                 elif value == 0:
                     print(
                         f"WARNING: Variable '{variable}' in product '{product.Name}' "
@@ -159,7 +159,9 @@ class Usecase:
 
                 new_quantity = None
                 for quantity in self.quantities:
-                    if quantity.Formula == self.settings["formula"] and len(self.settings["products"]) == 1: #Todo improve it
+                    if (
+                        quantity.Formula == self.settings["formula"] and len(self.settings["products"]) == 1
+                    ):  # Todo improve it
                         new_quantity = quantity
                         self.settings["ifc_class"] = quantity.is_a()
                         continue
@@ -184,23 +186,23 @@ class Usecase:
             self.update_cost_item_count()
 
     def get_value_from_pset(
-            self,
-            product:ifcopenshell.entity_instance,
-            v: str,
+        self,
+        product: ifcopenshell.entity_instance,
+        v: str,
     ) -> float:
         pset_name = v.split(".")[0]
         pset = ifcopenshell.util.element.get_pset(product, pset_name)
         pset_property_name = v.split(".")[1]
-        return (pset or {}).get(pset_property_name,None)
+        return (pset or {}).get(pset_property_name, None)
 
     def get_value_from_qset(
-            self,
-            product:ifcopenshell.entity_instance,
-            v: str,
+        self,
+        product: ifcopenshell.entity_instance,
+        v: str,
     ) -> float:
-        qtos = ifcopenshell.util.element.get_psets(product, qtos_only = True)
+        qtos = ifcopenshell.util.element.get_psets(product, qtos_only=True)
         quantities = next(iter(qtos.values()), {})
-        return (quantities or {}).get(v,None)
+        return (quantities or {}).get(v, None)
 
     def assign_cost_control(
         self, related_object: ifcopenshell.entity_instance, cost_item: ifcopenshell.entity_instance
@@ -243,6 +245,7 @@ class Usecase:
                             count += 1
                 quantity[3] = count
 
+
 OPERATORS = {
     ast.Add: operator.add,
     ast.Sub: operator.sub,
@@ -252,18 +255,20 @@ OPERATORS = {
     ast.USub: operator.neg,
 }
 
+
 def build_full_name(node):
-    #used for variables with dots
+    # used for variables with dots
     parts = []
     while isinstance(node, ast.Attribute):
-            parts.append(node.attr)
-            node = node.value
+        parts.append(node.attr)
+        node = node.value
 
     if isinstance(node, ast.Name):
         parts.append(node.id)
 
     return ".".join(reversed(parts))
 
+
 class VariableExtractor(ast.NodeVisitor):
     def __init__(self):
         self.variables = set()
@@ -274,6 +279,7 @@ class VariableExtractor(ast.NodeVisitor):
     def visit_Attribute(self, node):
         self.variables.add(build_full_name(node))
 
+
 class FormulaEvaluator(ast.NodeVisitor):
     def __init__(self, values):
         self.values = values
@@ -281,7 +287,7 @@ class FormulaEvaluator(ast.NodeVisitor):
     def visit_BinOp(self, node):
         left = self.visit(node.left)
         right = self.visit(node.right)
-        return OPERATORS[type(node.op)](left, right)
+        return OPERATORS[type(node.op)](left, right)  # ty: ignore[too-many-positional-arguments]
 
     def visit_Name(self, node):
         return self.values[node.id]

src/ifcopenshell-python/ifcopenshell/express/bootstrap.py

@@ -221,8 +221,7 @@ for id in to_emit:
     statements.append("%s << %s" % (id, stmt))
 
 if __name__ == "__main__":
-    print(
-        r"""
+    print(r"""
 # This file is generated by IfcOpenShell ifcexpressparser bootstrap.py
 
 from __future__ import annotations
@@ -261,6 +260,4 @@ if __name__ == "__main__":
         mdl = importlib.import_module(output)
         mdl.Generator(m).emit()
     sys.stdout.write(m.schema.name)
-"""
-        % ("\n        ".join(statements))
-    )
+""" % ("\n        ".join(statements)))

src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py

@@ -695,6 +695,7 @@ codegen_rule("MOD", lambda context: "%")
 codegen_rule("TRUE", lambda context: "True")
 codegen_rule("FALSE", lambda context: "False")
 
+
 def _dotted_name(node: ast.AST):
     """Return dotted name for Name/Attribute chains, else None."""
     if isinstance(node, ast.Name):
@@ -704,6 +705,7 @@ def _dotted_name(node: ast.AST):
         return f"{base}.{node.attr}" if base else node.attr
     return None
 
+
 class AttributeGetattrTransformer(ast.NodeTransformer):
     def visit_Attribute(self, node):
         parents = []
@@ -720,7 +722,7 @@ class AttributeGetattrTransformer(ast.NodeTransformer):
         if isinstance(node.ctx, ast.Store):
             return node
 
-        if _dotted_name(node) in ('ifcopenshell.create_entity', 'str.lower'):
+        if _dotted_name(node) in ("ifcopenshell.create_entity", "str.lower"):
             return node
 
         if node.attr.startswith("__"):

src/ifcopenshell-python/ifcopenshell/express/schema_class.py

@@ -363,24 +363,18 @@ class EarlyBoundCodeWriter:
             )
         )
 
-        self.statements[self.statements.index("{factory_placeholder}")] = (
-            """
+        self.statements[self.statements.index("{factory_placeholder}")] = """
 class %(schema_name)s_instance_factory : public IfcParse::instance_factory {
     virtual IfcUtil::IfcBaseClass* operator()(const IfcParse::declaration* decl, IfcEntityInstanceData&& data) const {
         %(instance_mapping)s
     }
 };
-"""
-            % locals()
-        )
+""" % locals()
 
         ""
-        self.statements[self.statements.index("{string_pool_placeholder}")] = (
-            """
+        self.statements[self.statements.index("{string_pool_placeholder}")] = """
 const std::string strings[] = {%s};
-"""
-            % ",".join(map(lambda s: '"%s"s' % s, self.strings))
-        )
+""" % ",".join(map(lambda s: '"%s"s' % s, self.strings))
 
     def __str__(self):
         return "\n".join(self.statements)

src/ifcopenshell-python/ifcopenshell/geom/app.py

@@ -145,8 +145,7 @@ class configuration:
             config.set(
                 "snippets",
                 "print all wall ids",
-                self.config_encode(
-                    """
+                self.config_encode("""
 ###########################################################################
 # A simple script that iterates over all walls in the current model       #
 # and prints their Globally unique IDs (GUIDS) to the console window      #
@@ -154,15 +153,13 @@ class configuration:
 
 for wall in model.by_type("IfcWall"):
     print ("wall with global id: "+str(wall.GlobalId))
-""".lstrip()
-                ),
+""".lstrip()),
             )
 
             config.set(
                 "snippets",
                 "print properties of current selection",
-                self.config_encode(
-                    """
+                self.config_encode("""
 ###########################################################################
 # A simple script that iterates over all IfcPropertySets of the currently #
 # selected object and prints them to the console                          #
@@ -180,8 +177,7 @@ if selection:
              for prop in relDefinesByProperties.RelatingPropertyDefinition.HasProperties:
                  print ("{:<20} :{}".format(prop.Name,prop.NominalValue.wrappedValue))
          print ("\\n")
-""".lstrip()
-                ),
+""".lstrip()),
             )
             with open(conf_file, "w") as configfile:
                 config.write(configfile)

src/ifcopenshell-python/ifcopenshell/ifcopenshell_wrapper.pyi

@@ -1697,10 +1697,16 @@ class uninitialized_tag: ...
 
 def arrange_polygons(settings, polygons): ...
 def clear_schemas(): ...
-def construct_iterator(geometry_library, settings, file, num_threads): ...
-def construct_iterator_with_include_exclude(geometry_library, settings, file, elems, include, num_threads): ...
-def construct_iterator_with_include_exclude_globalid(geometry_library, settings, file, elems, include, num_threads): ...
-def construct_iterator_with_include_exclude_id(geometry_library, settings, file, elems, include, num_threads): ...
+def construct_iterator(geometry_library, settings, file, num_threads, logger=...): ...
+def construct_iterator_with_include_exclude(
+    geometry_library, settings, file, elems, include, num_threads, logger=...
+): ...
+def construct_iterator_with_include_exclude_globalid(
+    geometry_library, settings, file, elems, include, num_threads, logger=...
+): ...
+def construct_iterator_with_include_exclude_id(
+    geometry_library, settings, file, elems, include, num_threads, logger=...
+): ...
 def convert_loop_to_function_item(loop): ...
 def create_box(*args): ...
 def create_epeck(*args): ...
@@ -1717,8 +1723,8 @@ def line_segments_to_polygons(s, eps, segments): ...
 def map_shape(settings, instance): ...
 def nary_union(sequence): ...
 def new_IfcBaseClass(schema_identifier: str, name: str) -> entity_instance: ...
-def open(fn: str, readonly: bool = False) -> file: ...
-def parse_ifcxml(filename): ...
+def open(fn: str, readonly: bool = False, logger=...) -> file: ...
+def parse_ifcxml(filename, logger=...): ...
 def polygons_to_svg(*args): ...
 def read(data): ...
 def register_schema(arg1): ...

src/ifcopenshell-python/ifcopenshell/util/alignment.py

@@ -56,7 +56,7 @@ def append_zero_length_segments(file: ifcopenshell.file) -> ifcopenshell.file:
     for alignment in alignments:
         layouts = ifcopenshell.api.alignment.get_alignment_layouts(alignment)
         for layout in layouts:
-            ifcopenshell.api.alignment.add_zero_length_segment(patched_file, layout, include_referent=False)
+            ifcopenshell.api.alignment.add_zero_length_segment(patched_file, layout)
             curve = ifcopenshell.api.alignment.get_layout_curve(layout)
             if curve:
                 ifcopenshell.api.alignment.add_zero_length_segment(patched_file, curve)

src/ifcopenshell-python/ifcopenshell/util/cost.py

@@ -355,8 +355,7 @@ def get_cost_rate(
 
 class CostValueUnserialiser:
     def parse(self, formula: str):
-        l = lark.Lark(
-            """start: formula
+        l = lark.Lark("""start: formula
                     formula: operand (operator operand)*
                     operand: value | category "(" formula ")"
                     value: NUMBER?
@@ -393,8 +392,7 @@ class CostValueUnserialiser:
                     NEWLINE: (CR? LF)+
 
                     %ignore WS // Disregard spaces in text
-                 """
-        )
+                 """)
         start = l.parse(formula)
         return self.get_formula(start.children[0])
 

src/ifcopenshell-python/ifcopenshell/util/selector.py

@@ -39,8 +39,7 @@ import ifcopenshell.util.shape
 import ifcopenshell.util.system
 import ifcopenshell.util.unit
 
-filter_elements_grammar = lark.Lark(
-    """start: filter_group
+filter_elements_grammar = lark.Lark("""start: filter_group
     filter_group: facet_list ("+" facet_list)*
     facet_list: facet ("," facet)*
 
@@ -111,11 +110,9 @@ filter_elements_grammar = lark.Lark(
     NEWLINE: (CR? LF)+
 
     %ignore WS // Disregard spaces in text
-"""
-)
+""")
 
-get_element_grammar = lark.Lark(
-    """start: keys
+get_element_grammar = lark.Lark("""start: keys
 
     keys: key ("." key)*
     key: quoted_string | regex_string | unquoted_string
@@ -130,11 +127,9 @@ get_element_grammar = lark.Lark(
     WS: /[ \\t\\f\\r\\n]/+
 
     %ignore WS // Disregard spaces in text
- """
-)
+ """)
 
-format_grammar = lark.Lark(
-    """start: expression
+format_grammar = lark.Lark("""start: expression
 
     ?expression: add_sub
     ?add_sub: mul_div
@@ -193,8 +188,7 @@ format_grammar = lark.Lark(
     NEWLINE: (CR? LF)+
 
     %ignore WS // Disregard spaces in text
-"""
-)
+""")
 
 
 class FormatTransformer(lark.Transformer):

src/ifcopenshell-python/test/api/alignment/test_add_positioning_referent.py

@@ -0,0 +1,100 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 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
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import ifcopenshell.api.alignment
+import ifcopenshell.api.context
+import ifcopenshell.api.unit
+import ifcopenshell.util.element
+
+
+def test_add_positioning_referent():
+    file = ifcopenshell.file(schema="IFC4X3")
+    project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
+    length = ifcopenshell.api.unit.add_si_unit(file, unit_type="LENGTHUNIT")
+    ifcopenshell.api.unit.assign_unit(file, units=[length])
+    geometric_representation_context = ifcopenshell.api.context.add_context(file, context_type="Model")
+    axis_model_representation_subcontext = ifcopenshell.api.context.add_context(
+        file,
+        context_type="Model",
+        context_identifier="Axis",
+        target_view="MODEL_VIEW",
+        parent=geometric_representation_context,
+    )
+
+    alignment = ifcopenshell.api.alignment.create(file, "TestAlignment", start_station=2000.0)
+
+    horizontal_layout = ifcopenshell.api.alignment.get_horizontal_layout(alignment)
+    segment = ifcopenshell.api.alignment.get_layout_segments(horizontal_layout)[0]
+
+    referent = ifcopenshell.api.alignment.add_positioning_referent(
+        file, "P.C.", alignment, distance_along=0.0, station=2000.0, positioned_product=segment
+    )
+
+    assert referent.is_a("IfcReferent")
+    assert referent.PredefinedType == "POSITION"
+    assert referent.Name == "P.C."
+    assert ifcopenshell.util.element.get_pset(element=referent, name="Pset_Stationing")
+    assert ifcopenshell.util.element.get_pset(element=referent, name="Pset_Stationing", prop="Station") == 2000.0
+    assert referent.ObjectPlacement != None
+
+    assert len(referent.Positions) == 1
+    rel_positions = referent.Positions[0]
+    assert rel_positions.is_a("IfcRelPositions")
+    assert rel_positions.RelatingPositioningElement == referent
+    assert rel_positions.RelatedProducts == (segment,)
+
+
+def test_add_positioning_referent_creates_separate_referent_per_call():
+    file = ifcopenshell.file(schema="IFC4X3")
+    project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
+    length = ifcopenshell.api.unit.add_si_unit(file, unit_type="LENGTHUNIT")
+    ifcopenshell.api.unit.assign_unit(file, units=[length])
+    geometric_representation_context = ifcopenshell.api.context.add_context(file, context_type="Model")
+    axis_model_representation_subcontext = ifcopenshell.api.context.add_context(
+        file,
+        context_type="Model",
+        context_identifier="Axis",
+        target_view="MODEL_VIEW",
+        parent=geometric_representation_context,
+    )
+
+    alignment = ifcopenshell.api.alignment.create(file, "TestAlignment", start_station=2000.0)
+
+    horizontal_layout = ifcopenshell.api.alignment.get_horizontal_layout(alignment)
+    segment = ifcopenshell.api.alignment.get_layout_segments(horizontal_layout)[0]
+
+    first_referent = ifcopenshell.api.alignment.add_positioning_referent(
+        file, "P.C.", alignment, distance_along=0.0, station=2000.0, positioned_product=segment
+    )
+
+    other_product = file.createIfcBuildingElementProxy(GlobalId=ifcopenshell.guid.new(), Name="Sign")
+    second_referent = ifcopenshell.api.alignment.add_positioning_referent(
+        file, "P.C.", alignment, distance_along=0.0, station=2000.0, positioned_product=other_product
+    )
+
+    # each call creates its own IfcReferent, each with its own IfcRelPositions to the product passed in
+    assert first_referent != second_referent
+    assert len(first_referent.Positions) == 1
+    assert first_referent.Positions[0].RelatedProducts == (segment,)
+    assert len(second_referent.Positions) == 1
+    assert second_referent.Positions[0].RelatedProducts == (other_product,)
+
+
+test_add_positioning_referent()
+test_add_positioning_referent_creates_separate_referent_per_call()

src/ifcopenshell-python/test/api/alignment/test_add_stationing_referent.py

@@ -0,0 +1,115 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2025 Thomas Krijnen <thomas@aecgeeks.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 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
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import ifcopenshell.api.alignment
+import ifcopenshell.api.context
+import ifcopenshell.api.unit
+import ifcopenshell.util.element
+
+
+def _create_test_file():
+    file = ifcopenshell.file(schema="IFC4X3")
+    project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
+    length = ifcopenshell.api.unit.add_si_unit(file, unit_type="LENGTHUNIT")
+    ifcopenshell.api.unit.assign_unit(file, units=[length])
+    geometric_representation_context = ifcopenshell.api.context.add_context(file, context_type="Model")
+    axis_model_representation_subcontext = ifcopenshell.api.context.add_context(
+        file,
+        context_type="Model",
+        context_identifier="Axis",
+        target_view="MODEL_VIEW",
+        parent=geometric_representation_context,
+    )
+    return file
+
+
+def _create_test_alignment_with_vertical(file):
+    # include_vertical=True so that get_curve() (IfcGradientCurve, on the "Axis" representation)
+    # and get_basis_curve() (IfcCompositeCurve, on the "FootPrint" representation) are different
+    # entities, letting the on_basis_curve option be observed.
+    alignment = ifcopenshell.api.alignment.create(file, "TestAlignment", include_vertical=True, start_station=0.0)
+    assert ifcopenshell.api.alignment.get_basis_curve(alignment).is_a("IfcCompositeCurve")
+    assert ifcopenshell.api.alignment.get_curve(alignment).is_a("IfcGradientCurve")
+    assert ifcopenshell.api.alignment.get_basis_curve(alignment) != ifcopenshell.api.alignment.get_curve(alignment)
+    return alignment
+
+
+def _assert_common_referent_asserts(referent, name, station):
+    assert referent.is_a("IfcReferent")
+    assert referent.PredefinedType == "STATION"
+    assert referent.Name == name
+    assert ifcopenshell.util.element.get_pset(element=referent, name="Pset_Stationing")
+    assert ifcopenshell.util.element.get_pset(element=referent, name="Pset_Stationing", prop="Station") == station
+    assert referent.ObjectPlacement != None
+
+
+def test_add_stationing_referent_on_basis_curve_none_defaults_to_basis_curve():
+    # on_basis_curve=None should behave the same as on_basis_curve=True
+    file = _create_test_file()
+    alignment = _create_test_alignment_with_vertical(file)
+
+    referent = ifcopenshell.api.alignment.add_stationing_referent(
+        file, "1+00.000", alignment, distance_along=100.0, station=100.0, on_basis_curve=None
+    )
+
+    _assert_common_referent_asserts(referent, "1+00.000", 100.0)
+
+    assert referent.ObjectPlacement.is_a("IfcLinearPlacement")
+    assert referent.ObjectPlacement.RelativePlacement.Location.BasisCurve == ifcopenshell.api.alignment.get_basis_curve(
+        alignment
+    )
+
+
+def test_add_stationing_referent_on_basis_curve_true():
+    file = _create_test_file()
+    alignment = _create_test_alignment_with_vertical(file)
+
+    referent = ifcopenshell.api.alignment.add_stationing_referent(
+        file, "1+00.000", alignment, distance_along=100.0, station=100.0, on_basis_curve=True
+    )
+
+    _assert_common_referent_asserts(referent, "1+00.000", 100.0)
+
+    assert referent.ObjectPlacement.is_a("IfcLinearPlacement")
+    assert referent.ObjectPlacement.RelativePlacement.Location.BasisCurve == ifcopenshell.api.alignment.get_basis_curve(
+        alignment
+    )
+
+
+def test_add_stationing_referent_on_basis_curve_false():
+    # with a vertical layout present, on_basis_curve=False positions the referent on the
+    # alignment curve (IfcGradientCurve) rather than on the basis curve (IfcCompositeCurve).
+    file = _create_test_file()
+    alignment = _create_test_alignment_with_vertical(file)
+
+    referent = ifcopenshell.api.alignment.add_stationing_referent(
+        file, "1+00.000", alignment, distance_along=100.0, station=100.0, on_basis_curve=False
+    )
+
+    _assert_common_referent_asserts(referent, "1+00.000", 100.0)
+
+    assert referent.ObjectPlacement.is_a("IfcLinearPlacement")
+    basis_curve = referent.ObjectPlacement.RelativePlacement.Location.BasisCurve
+    assert basis_curve == ifcopenshell.api.alignment.get_curve(alignment)
+    assert basis_curve != ifcopenshell.api.alignment.get_basis_curve(alignment)
+
+
+test_add_stationing_referent_on_basis_curve_none_defaults_to_basis_curve()
+test_add_stationing_referent_on_basis_curve_true()
+test_add_stationing_referent_on_basis_curve_false()

src/ifcopenshell-python/test/api/alignment/test_add_stationing_to_alignment.py

@@ -48,5 +48,26 @@ def test_add_stationing_to_alignment():
     assert ifcopenshell.util.element.get_pset(element=referent, name="Pset_Stationing", prop="Station") == 2000.0
     assert referent.ObjectPlacement != None
 
+    # add a station equation at 1000 distance along. this is station 3+000 in coming and 4+000 outgoing.
+    # this is a gap equation.
+    second_referent = ifcopenshell.api.alignment.add_stationing_referent(
+        file, "4+000.000", alignment, distance_along=1000.0, station=4000.0, incoming_station=3000.0
+    )
+
+    referent_nest = ifcopenshell.api.alignment.get_referent_nest(file, alignment)
+    assert len(referent_nest.RelatedObjects) == 2
+
+    assert second_referent == referent_nest.RelatedObjects[1]
+
+    assert second_referent.PredefinedType == "STATION"
+    assert second_referent.Name == "4+000.000"
+    assert ifcopenshell.util.element.get_pset(element=second_referent, name="Pset_Stationing")
+    assert ifcopenshell.util.element.get_pset(element=second_referent, name="Pset_Stationing", prop="Station") == 4000.0
+    assert (
+        ifcopenshell.util.element.get_pset(element=second_referent, name="Pset_Stationing", prop="IncomingStation")
+        == 3000.0
+    )
+    assert second_referent.ObjectPlacement != None
+
 
 test_add_stationing_to_alignment()

src/ifcopenshell-python/test/api/alignment/test_create_representation.py

@@ -21,9 +21,12 @@ import math
 
 import pytest
 import ifcopenshell
+import ifcopenshell.api.aggregate
 import ifcopenshell.api.alignment
+import ifcopenshell.api.context
+import ifcopenshell.api.spatial
 import ifcopenshell.api.unit
-import numpy as np
+import ifcopenshell.util.unit
 
 
 def test_create_representation():

src/ifcopenshell-python/test/api/alignment/test_distance_along_from_station.py

@@ -53,4 +53,56 @@ def test_distance_along_from_station():
     assert ifcopenshell.api.alignment.distance_along_from_station(file, alignment, 17525.36) == pytest.approx(7525.36)
 
 
+def test_distance_along_from_station_with_station_equations():
+    # Reproduces the worked example from the IFC Alignment Geometry Implementation Guide, chapter 9.2.6:
+    # a gap equation (P3: incoming 14+00.00, outgoing 17+00.00) and an overlap equation
+    # (P4: incoming 19+00.00, outgoing 18+50.00).
+    file = ifcopenshell.file(schema="IFC4X3")
+    project = file.createIfcProject(GlobalId=ifcopenshell.guid.new(), Name="Test")
+    length = ifcopenshell.api.unit.add_conversion_based_unit(file, name="foot")
+    ifcopenshell.api.unit.assign_unit(file, units=[length])
+    geometric_representation_context = ifcopenshell.api.context.add_context(file, context_type="Model")
+    axis_model_representation_subcontext = ifcopenshell.api.context.add_context(
+        file,
+        context_type="Model",
+        context_identifier="Axis",
+        target_view="MODEL_VIEW",
+        parent=geometric_representation_context,
+    )
+
+    coordinates = [(500.0, 2500.0), (3340.0, 660.0), (4340.0, 5000.0), (7600.0, 4560.0), (8480.0, 2010.0)]
+    radii = [(1000.0), (1250.0), (950.0)]
+    vpoints = [(0.0, 100.0), (2000.0, 135.0), (5000.0, 105.0), (7400.0, 153.0), (9800.0, 105.0), (12800.0, 90.0)]
+    lengths = [(1600.0), (1200.0), (2000.0), (800.0)]
+
+    alignment = ifcopenshell.api.alignment.create_by_pi_method(
+        file, "TestAlignment", coordinates, radii, vpoints, lengths, start_station=1000.0
+    )
+
+    ifcopenshell.api.alignment.add_stationing_referent(
+        file, "P3", alignment, distance_along=400.0, station=1700.0, incoming_station=1400.0
+    )
+    ifcopenshell.api.alignment.add_stationing_referent(
+        file, "P4", alignment, distance_along=600.0, station=1850.0, incoming_station=1900.0
+    )
+
+    distance_along_from_station = ifcopenshell.api.alignment.distance_along_from_station
+
+    # between P2 and P3: Sta. 13+00.00
+    assert distance_along_from_station(file, alignment, 1300.0) == pytest.approx(300.0)
+
+    # between P3 and P4: Sta. 18+00.00
+    assert distance_along_from_station(file, alignment, 1800.0) == pytest.approx(500.0)
+
+    # between P4 and P5: Sta. 19+25.00
+    assert distance_along_from_station(file, alignment, 1925.0) == pytest.approx(675.0)
+
+    # Sta. 15+00.00 falls inside the gap opened by the equation at P3 and has no corresponding distance along
+    assert distance_along_from_station(file, alignment, 1500.0) is None
+
+    # Sta. 18+75.00 falls inside the overlap zone at P4; the post-equation (outgoing) match is returned
+    assert distance_along_from_station(file, alignment, 1875.0) == pytest.approx(625.0)
+
+
 test_distance_along_from_station()
+test_distance_along_from_station_with_station_equations()

src/ifcopenshell-python/test/test_parse.py

@@ -1,5 +1,6 @@
 import ifcopenshell
 
+
 def test_skip_over_non_entity_instance():
     data = """
 ISO-10303-21;

src/ifcopenshell-python/test/test_rules.py

@@ -46,4 +46,4 @@ def test_file(filename):
 
 
 if __name__ == "__main__":
-    pytest.main(["-sx", __file__, '--import-mode=importlib'])
+    pytest.main(["-sx", __file__, "--import-mode=importlib"])

src/ifcparse/IfcUtil.cpp

@@ -187,6 +187,15 @@ void IfcUtil::sanitate_material_name(std::string& str) {
 }
 
 void IfcUtil::escape_xml(std::string& str) {
+    // Strip characters that are illegal in XML 1.0. Control characters other
+    // than tab (0x09), newline (0x0A) and carriage return (0x0D) are not valid
+    // XML 1.0 characters and cannot even be represented as numeric character
+    // references, so they would otherwise make the serialized XML/SVG output
+    // non-well-formed. Bytes belonging to a valid UTF-8 multibyte sequence are
+    // always >= 0x80, so filtering on the low control range leaves them intact.
+    str.erase(std::remove_if(str.begin(), str.end(), [](unsigned char c) {
+        return c < 0x20 && c != '\t' && c != '\n' && c != '\r';
+    }), str.end());
     boost::replace_all(str, "&", "&amp;");
     boost::replace_all(str, "\"", "&quot;");
     boost::replace_all(str, "'", "&apos;");

src/ifcpatch/ifcpatch/recipes/ExtractElements.py

@@ -111,7 +111,7 @@ class Patcher(ifcpatch.BasePatcher):
         if element.is_a("IfcProject"):
             proj = self.new.add(element)
             for ctx in element.RepresentationContexts or ():
-                for coop in getattr(ctx, 'HasCoordinateOperation', ()):
+                for coop in getattr(ctx, "HasCoordinateOperation", ()):
                     self.new.add(coop)
             return proj
         return ifcopenshell.api.project.append_asset(

src/ifcpatch/test/test_DowngradeIndexedPolyCurve.py

@@ -33,9 +33,7 @@ class TestDowngradeIndexedPolyCurve(test.bootstrap.IFC4):
             Points=point_list,
             Segments=segments,
         )
-        self.file.create_entity(
-            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
-        )
+        self.file.create_entity("IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve)
         return curve
 
     def test_run_without_segments(self):
@@ -80,9 +78,7 @@ class TestDowngradeIndexedPolyCurve(test.bootstrap.IFC4):
             Points=point_list,
             Segments=[self.file.createIfcLineIndex((1, 2, 3, 4, 1))],
         )
-        self.file.create_entity(
-            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
-        )
+        self.file.create_entity("IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve)
         ifcpatch.execute(
             {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
         )
@@ -110,9 +106,7 @@ class TestDowngradeIndexedPolyCurve(test.bootstrap.IFC4):
                 self.file.createIfcLineIndex((3, 4)),
             ],
         )
-        self.file.create_entity(
-            "IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve
-        )
+        self.file.create_entity("IfcArbitraryClosedProfileDef", ProfileType="AREA", OuterCurve=curve)
         ifcpatch.execute(
             {"input": "input.ifc", "file": self.file, "recipe": "DowngradeIndexedPolyCurve", "arguments": []}
         )

src/ifcwrap/IfcGeomWrapper.i

@@ -977,12 +977,14 @@ struct ShapeRTTI : public boost::static_visitor<PyObject*>
 			if (item == nullptr) {
 				throw IfcParse::IfcException("Failed to convert placement");
 			}
+			/*
             if (st.get<ifcopenshell::geometry::settings::ConvertBackUnits>().get()) {
                 // we pass the settings to the Transformation object, but access the data just offloads to the
                 // generic cartesian_base<Matrix4> so there's no time to apply the settings to the translation part.
                 item = ifcopenshell::geometry::taxonomy::matrix4::ptr(item->clone_());
                 item->components().col(3).head<3>() /= kernel.settings().get<ifcopenshell::geometry::settings::LengthUnit>().get();
             }
+			*/
 			return new IfcGeom::Transformation(kernel.settings(), item);
 		} else {
 			if (!representation) {

src/serializers/schema_dependent/XmlSerializer.cpp

@@ -305,7 +305,7 @@ ptree* descend(Logger& logger, ifcopenshell::geometry::abstract_mapping* mapping
 			<IfcSchema::IfcObject, IfcSchema::IfcRelDefinesByProperties, IfcSchema::IfcPropertySetDefinition>
 			(logger, object, &IfcSchema::IfcObject::IsDefinedBy, &IfcSchema::IfcRelDefinesByProperties::RelatingPropertyDefinition);
 
-#ifdef SCHEMAS_HAS_IfcPropertySetDefinitionSet
+#ifdef SCHEMA_HAS_IfcPropertySetDefinitionSet
 		aggregate_of<IfcSchema::IfcPropertySetDefinitionSet>::ptr property_set_sets = get_related
 			<IfcSchema::IfcObject, IfcSchema::IfcRelDefinesByProperties, IfcSchema::IfcPropertySetDefinitionSet>
 			(logger, object, &IfcSchema::IfcObject::IsDefinedBy, &IfcSchema::IfcRelDefinesByProperties::RelatingPropertyDefinition);