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Dion Moult
9db42df81c
Battle-testing real sidecars over HTTP Range exposed severe thrash: a
531 MB model re-fetched 2.25 GB (4×) and never converged — viewAll puts
the whole model in frustum, so every chunk wants to be resident, and the
web async path made it worse two ways:
- A web load only consumes pool space when it COMPLETES (async), so the
per-frame issuance over-committed the pool; completions then failed
applyStreamedChunk on a full pool, the chunk re-candidated with no
cooldown, and re-fetched every frame.
- Pool growth is itself async on web (provisional sub-buffers validated
off the JS event loop), so even fetched chunks failed to alloc until
the pool caught up, and re-fetched.
Fix: gate web chunk issuance on VALIDATED free space + in-flight
reservation, and grow the pool BEFORE fetching:
- streaming_web_inflight_bytes_ reserves each in-flight load's footprint
so we never have more bytes in flight than the pool can place.
- When a visible chunk doesn't fit validated free, don't fetch — call
pool_.requestGrowth() (BufferPool: drives the async provisional grow
without allocating) and short-back-off; the chunk is fetched once,
after space exists. When the pool is saturated (model > GPU memory),
long-cooldown so a never-fitting chunk isn't re-fetched. Gating before
the evictor also kills phase-2 visible↔visible swap thrash.
- On async load failure, cool down (short if the pool can still grow,
long if saturated) instead of re-candidating next frame.
Result (manual battle tool, host.mjs + real files): 531 MB now loads
23/23 chunks, 322 MB loads 14/14 — resident climbs monotonically with
ZERO thrash warnings and a stable resident set, vs the old re-fetch loop.
The whole model resides on the GPU and stays. (Remaining ~3× ramp
over-fetch — per-chunk re-loads during the async-growth ramp + read
amplification from chunk byte-locality — is a separate efficiency
follow-up, not thrash.) 6/6 web smoke + 107/107 unit pass; desktop
unaffected (the gate is web-only; requestGrowth is a no-op wrapper there).
Co-Authored-By: Claude Opus 4.8 <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* |