The DATA section is split into one chunk per thread and each worker runs the same per-instance reader as the serial parse over its own reader, storage, inverse records and simple-type list; the results are merged in file order, so instance order, GlobalId precedence and inverse records are identical to the serial parse. Reference resolution then splits over the same threads: each instance's slots are its own and the name table is complete and read-only by then. The default is one thread per core, capped at 16; IFCOPENSHELL_PARSE_THREADS or file::parse_threads() overrides it, and 1 parses as before. The instance headers are read by one loop, for_each_instance_header(), shared with the lazy index: it looks declarations up once per keyword, passes over a bypassed instance's attribute list and slides past a stray keyword the way the serial reader does (the lazy index therefore no longer falls back on one). Finding the split points is the one place that looks at raw bytes rather than tokens, because tokenizing the file serially first would leave nothing to parallelise. It applies three rules: a string starts and ends at a quote and cannot span a line, and a comment runs from /* to */; a split is a '#' that starts a line outside both. Getting a string's end wrong can only lose a candidate, never accept a wrong one, since no string contains a newline. The equality test puts a comment holding a fake instance and a string holding "/*" between the chunks. file_reader gains for_each_span(), which hands a byte range out span by span (one span for a buffer, one per page for the paged reader), and reopen(), a reader over the same file for another thread. TXG 58 MB / 210_King 147 MB / OKgate22 231 MB, 12 threads: 0.44 / 1.24 / 2.01 s against 1.07 / 2.75 / 5.12 s on one thread; memory after the parse within 1–4%, peak +5–4%. This commit was written by an AI coding tool and has not been verified by a human. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013wcN7XquTfUi4vsKQ4KchL
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* |
| ifcgeomserver | 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* |
| serializers | Internal library for IfcOpenShell | LGPL-3.0-or-later* |