Omniverse CAD Converter (usd-convert-cad)

Pip-installable Omniverse CAD Converter package for converting supported CAD assets to OpenUSD.

usd-convert-cad converts supported CAD, AEC, and interchange files to OpenUSD. The wheel includes the converter command line, Python package, required native runtime components, and the canonical agent skill.

This documentation was tested with usd-convert-cad==0.3.0 on Python 3.12. For a different installed version, confirm its options with usd-convert-cad --help.

Installing

Create an isolated Python environment and install the package:

python -m venv .venv
python -m pip install usd-convert-cad

Converting Files

Run the console command with an input CAD asset and output USD path:

usd-convert-cad --input model.stp --output model.usdc

Short flags are also supported:

usd-convert-cad -i model.stp -o model.usda

The package supports module execution as well:

python -m usd_convert_cad --input model.stp --output model.usdc

Output Formats

The output path determines the USD file format. Supported output extensions are .usd, .usda, .usdc, and .usdz. USDZ export converts to a temporary {stem}.usdc layer in an isolated staging directory, then packages it with OpenUSD. USDZ requires monolithic conversion (--composition-style none, the default). Packaging writes to a temporary archive and replaces the final .usdz only on success. If --material-type preview-surface-omnipbr is set, USDZ export switches to preview-surface because OmniPBR materials are not packageable.

Examples:

usd-convert-cad -i assembly.stp -o assembly.usdc
usd-convert-cad -i part.igs -o part.usda
usd-convert-cad -i model.prt -o model.usd
usd-convert-cad -i assembly.stp -o assembly.usdz

Conversion Options

Run usd-convert-cad --help to view all options.

Options include:

• --global-xforms: Author global transforms instead of local transforms.
• --convert-curves: Convert wire and curve geometry, including 2D and 3D geometry data, to USD BasisCurves. See LIMITATIONS.md for 2D conversion limitations.
• --convert-metadata: Convert CAD metadata to USD custom attributes.
• --read-constraints: Export CATIA V5, NX, and SolidWorks Fix, CATIA V5 Fix Together, NX Bond, and SolidWorks Lock mate assembly constraints as USD Physics fixed joints while preserving world or relative poses.
• --no-dedup: Disable mesh and material deduplication.
• --tess-lod <0-4>: Set tessellation level of detail.
• --revit-lod <0-3>: Set Revit detail level. Values are 0 for file default, 1 coarse, 2 medium, and 3 fine.
• --accurate-tessellation: Enable accurate tessellation.
• --fast-surface-curvatures: Disable accurate surface curvature computation.
• --no-normals: Do not author normals.
• --no-materials: Do not author materials.
• --material-type <type>: Choose material output type. Valid values: none, preview-surface, preview-surface-omnipbr, and preview-surface-materialx. The MaterialX option authors OpenPBR for the mtlx render context and includes a Preview Surface fallback.
• --up-axis <axis>: Override output stage up-axis. Valid values: file, y, z.
• --instancing-style <style>: Choose how repeated components are authored. Valid values: none, reference, instanceable-reference.
• --composition-style <style>: Choose how external sub-assemblies and parts are authored. Valid values: none, reference, payload.
• --filter-style <style>: Choose how hidden CAD elements are converted. Valid values: none, omit, hide, deactivate.
• --load-hidden: Load hidden CAD elements before filtering.
• --progress: Print converter progress.
• --progress-frequency <hz>: Set progress report frequency in Hz.
• --creator <value>: Set creator metadata on output USD layers.
• --convert-physics-data: Author physical properties on USD prims.
• --physics-accuracy-level <0.0-1.0>: Set physical property accuracy.
• --physics-use-geometry-on-ribrep: Use geometry instead of topology for RiBRep physical properties.
• --view-layer-name <name>: Convert a CAD view layer or simplified representation by name.

Pass the selected value after the option name:

usd-convert-cad \
  --input model.stp \
  --output model.usdc \
  --convert-metadata \
  --tess-lod 3 \
  --material-type preview-surface \
  --up-axis z \
  --instancing-style instanceable-reference \
  --composition-style payload \
  --filter-style hide \
  --progress-frequency 4 \
  --progress

Python Package

The installed Python package exposes version helpers:

import usd_convert_cad

print(usd_convert_cad.__version__)
print(usd_convert_cad.get_version())

The wheel also installs the canonical agent skill at usd_convert_cad/skills/omniverse-cad-to-usd/SKILL.md.

Uninstalling

python -m pip uninstall usd-convert-cad

License and Third-Party Notices

The Omniverse CAD Converter is governed by the applicable NVIDIA Omniverse licensing terms. NVIDIA licenses the Tech Soft 3D HOOPS Exchange SDK to read supported CAD data for conversion to OpenUSD. See the repository license and third-party notices.