Closes the loop on stage 4 (pick): clicking an object now highlights it
on screen. Plus the prerequisite plumbing for selection to behave
correctly across multi-sidecar loads.
Pieces:
1. WgpuSelectionState (new header)
CPU-side multi-set + active-id, mirroring the GL Selection.h shape
but pure stdlib (no Qt deps) so it can move into ifcviewer-core
later without dragging Qt across. clear/replace/add/remove/toggle
APIs + a fillFlagsArray helper that packs (selected, active) into
a u32 bitmap indexed by object_id.
2. selection_flags storage buffer + frame_bgl bump to 2 entries
Indexed by object_id, bit 0 = selected, bit 1 = active. Lives in
the frame bind group (group=0 binding=1) because object_ids are
globally unique — making it model-scoped would be the wrong cut.
ensureSelectionFlagsBuffer grows geometrically (64 → 128 → … u32)
as new models push next_object_id_ up, rebuilds the frame bind
group when it does.
3. Global object_id rebase in applyCachedModel
Each sidecar's local ids start from 1 and collide across files;
pick was previously ambiguous on multi-model loads. We now add
next_object_id_ as a base offset, rewrite InstanceCpu.object_id
(CPU mirror stays consistent) + InstanceGpu.object_id (what pick
reads back), and bump next_object_id_ by the model's max + 1.
4. WGSL main fragment reads sel_flags
Vertex shader passes inst.object_id through to fragment as
@interpolate(flat). Fragment reads sel_flags[object_id], mixes
(0.2, 0.6, 1.0) at 0.45 for in-selection and (0.4, 0.8, 1.0) at
0.40 on top for active. Same constants as the GL main shader.
5. Mouse → selection
LMB-click-without-drag pick result feeds the selection:
no modifier → replace
Shift → add
Ctrl → remove (active migrates to another id in the set)
miss + no modifier → clear
uploadSelectionFlagsIfDirty repacks + writes the GPU bitmap at
the top of the next render(); no upload on still frames.
Pick pipeline is unchanged — it already outputs the per-instance
object_id, and that's what the selection storage indexes.
Visibility + clip planes are pending follow-ups in stage 5 (mostly
small, share the same buffer-lifecycle pattern). Edge silhouette
(stage 9 partial), --screenshot diff harness (stage 10 partial),
ifcviewer-core extract (stage 12), and web chunking (stage 13) all
still pending.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
IfcOpenShell
IfcOpenShell is an open source (LGPL) software library for working with Industry Foundation Classes (IFC). Complete parsing support is provided for IFC2x3 TC1, IFC4 Add2 TC1, IFC4x1, IFC4x2, and IFC4x3 Add2. Extensive geometric support is implemented for the IFC releases IFC2x3 TC1 and IFC4 Add2 TC1. Extending with support for arbitrary IFC schemas is possible at compile-time when using C++ and at run-time when using Python.
In addition to a C++ and Python API, IfcOpenShell comes with an ecosystem of tools, notably including IfcConvert (an application to convert IFC models to other formats), Bonsai (an add-on to Blender providing a graphical IFC authoring platform), and many other libraries, CLI apps, and more. Support is also provided for auxiliary standards such as BCF and IDS.
For more information, see:
Development is sponsored through your generous donations!
Contents
| Name | Description | License | Service |
|---|---|---|---|
| bcf | Library to read and write BCF-XML and query OpenCDE BCF-API modules | LGPL-3.0-or-later | |
| bonsai | Add-on to Blender providing a graphical native IFC authoring platform | GPL-3.0-or-later | |
| bsdd | Library to query the bSDD API | LGPL-3.0-or-later | |
| ifc2ca | Utility to convert IFC structural analysis models to Code_Aster | LGPL-3.0-or-later | |
| ifc4d | Convert to and from IFC and project management software | LGPL-3.0-or-later | |
| ifc5d | Report and optimise cost information from IFC | LGPL-3.0-or-later | |
| ifcbimtester | Wrapper for Gherkin based unit testing for IFC models | LGPL-3.0-or-later | |
| ifcblender | Historic Blender IFC import add-on | LGPL-3.0-or-later* | |
| ifccityjson | Convert CityJSON to IFC | LGPL-3.0-or-later | |
| ifcclash | Clash detection library and CLI app | LGPL-3.0-or-later | |
| ifcconvert | CLI app to convert IFC to many other formats | LGPL-3.0-or-later* | |
| ifccsv | Library and CLI app to export and import schedules from IFC | LGPL-3.0-or-later | |
| ifcdiff | Compare changes between IFC models | LGPL-3.0-or-later | |
| ifcedit | CLI wrapper for ifcopenshell.api IFC model mutation functions | LGPL-3.0-or-later | |
| ifcfm | Extract IFC data for FM handover requirements | LGPL-3.0-or-later | |
| ifcmax | Historic extension for IFC support in 3DS Max | LGPL-3.0-or-later* | |
| ifcmcp | MCP server for querying and editing IFC building models | LGPL-3.0-or-later | |
| ifcopenshell-python | Python library for IFC manipulation | LGPL-3.0-or-later* | |
| ifcpatch | Utility to run pre-packaged scripts to manipulate IFCs | LGPL-3.0-or-later | |
| ifcquery | CLI tool for querying and inspecting IFC building models | LGPL-3.0-or-later | |
| ifcsverchok | Blender Add-on for visual node programming with IFC | GPL-3.0-or-later | |
| ifctester | Library, CLI and webapp for IDS model auditing | LGPL-3.0-or-later |
The IfcOpenShell C++ codebase is split into multiple interal libraries:
| Name | Description | License |
|---|---|---|
| ifcgeom | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcgeom_schema_agnostic | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcgeomserver | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcjni | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcparse | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| ifcwrap | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| qtviewer | Internal library for IfcOpenShell | LGPL-3.0-or-later* |
| serializers | Internal library for IfcOpenShell | LGPL-3.0-or-later* |