Omniverse Cad To Usd

Omniverse CAD to USD

When to Use

Use this skill when a user asks to:

• Convert supported CAD, 3D, or interchange files to OpenUSD with the standalone usd-convert-cad Python wheel.
• Convert supported CAD inputs using the usd-convert-cad converter and its Parameters option policy.
• Call CAD-to-USD conversion from a higher-level Physical AI workflow without duplicating converter setup.
• Discover documented converter options from the installed wheel before choosing overrides.
• Explain how HOOPS Exchange concepts map to OpenUSD prims, attributes, materials, units, or composition arcs.

Do not use this skill to substitute mesh converters, hand-authored USD, or unrelated tools for CAD conversion.

What Changed

This skill no longer installs Omniverse Kit or pulls a CAD converter extension from the Kit registry. Conversion now runs entirely inside the self-contained usd-convert-cad wheel published to PyPI. The wheel bundles its own OpenUSD and CAD conversion runtime, so there is no Kit app, no registry pull, no config.env, and no EULA prompt.

Instructions

1. Confirm the source file exists and detect the file type by extension.
2. Confirm the extension is listed under Supported Formats. For AutoCAD (.dwg, .dxf) and Revit (.rvt, .rfa) inputs, first check the platform: these formats are not supported on linux-aarch64 (see Platform Support). On linux-aarch64, do not attempt the conversion — report the platform limitation instead.
3. Create or reuse an isolated Python 3.12 virtual environment for the wheel. The wheel bundles its own OpenUSD (pxr) runtime, so isolating it prevents conflicts with any other pxr distribution in a shared interpreter.
   • Create: python3.12 -m venv .venv, or py -3.12 -m venv .venv on Windows.
   • Activate: .venv\Scripts\Activate.ps1 (PowerShell), .venv\Scripts\activate.bat (cmd.exe), or source .venv/bin/activate (bash). Or skip activation and call the interpreter directly: .venv\Scripts\python.exe (Windows) or .venv/bin/python (Linux).
4. Ensure the wheel is installed in that environment. Probe with python -c "import usd_convert_cad" or usd-convert-cad --help. If it is missing, install it with python -m pip install usd-convert-cad.
5. Run the conversion with the usd-convert-cad console command (or python -m usd_convert_cad), passing -i <input> and -o <output>. Choose the output extension (.usd, .usda, or .usdc).
6. Treat the process exit code as the authoritative result: 0 means success, non-zero means failure. On success the tool prints Successfully converted: <output>; confirm the output file exists.
7. On failure, read stderr. The tool prints Error: conversion failed with code <n> followed by the converter error message.
8. For option-discovery questions, run usd-convert-cad --help to read the documented options for the installed wheel version before recommending overrides.
9. For mapping, BIM, unit, metadata, material, instancing, or Revit room/space questions, read ../../docs/concept_mapping.md before answering.

Output Format

Supported export formats:

• .usd
• .usda
• .usdc

The output path's extension determines the USD file format. USDZ (.usdz) export is not supported yet.

Recommended external caller contract:

usd-convert-cad --input asset.jt --output asset.usdc

The console command returns exit code 0 on success and prints Successfully converted: <output>; it returns a non-zero exit code and prints the converter error message to stderr on failure. External callers should branch on the exit code and confirm the output file exists before continuing to USD validation or SimReady workflows. The wheel writes only the requested output file (and any sidecars the chosen USD format implies); it does not create a separate JSON status report.

Prerequisites

The only prerequisite is the installed wheel. Install it into an isolated Python 3.12 virtual environment so its bundled OpenUSD (pxr) runtime cannot conflict with another pxr in a shared interpreter.

Notes:

• The wheel is self-contained: it bundles its own OpenUSD and CAD conversion runtime. It does not depend on omniverse-kit, usd-core, or a separately installed pxr.
• Use a dedicated virtual environment per the table above. Because the wheel ships its own pxr, installing it into an interpreter that already exposes a different OpenUSD distribution can cause import conflicts.
• If the wheel is hosted on an NVIDIA package index rather than public PyPI, add the appropriate index, for example python -m pip install usd-convert-cad --extra-index-url https://pypi.nvidia.com.

Supported Formats

Platform Support

Most formats convert on all supported platforms (windows-x86_64, linux-x86_64, linux-aarch64). The exceptions are the AutoCAD and Revit formats:

The underlying HOOPS Exchange DWG/Revit readers are not available for linux-aarch64, so attempting to convert these formats on that platform fails with A3D_LOAD_INVALID_FILE_FORMAT (error code -10005) and produces no output. Do not attempt DWG/DXF or RVT/RFA conversion on linux-aarch64; treat those inputs as unsupported on that platform and report the platform limitation instead of retrying.

Converter Policy

Use the installed usd-convert-cad wheel. There is one supported converter core. Do not substitute mesh converters, hand-authored USD, or unrelated tools for CAD conversion.

Concept Mapping

Read ../../docs/concept_mapping.md when a user asks how source CAD concepts become OpenUSD. The document covers HOOPS product occurrences, part definitions, representation items, tessellation, materials, source metadata, hidden state, units, instancing, and composition arcs.

Commands

Create an isolated environment, install, and verify:

python -m venv .venv
# Windows (PowerShell): .venv\Scripts\Activate.ps1
# Windows (cmd.exe):    .venv\Scripts\activate.bat
# Linux/macOS (bash):   source .venv/bin/activate
python -m pip install usd-convert-cad
usd-convert-cad --help
python -c "import usd_convert_cad; print(usd_convert_cad.__version__)"

Convert with the default options:

usd-convert-cad --input asset.jt --output asset.usd
usd-convert-cad -i site.dgn -o site.usdc
python -m usd_convert_cad -i assembly.step -o assembly.usdc

Apply documented converter options:

usd-convert-cad -i asset.jt -o asset.usdc --tess-lod 4
usd-convert-cad -i assembly.step -o assembly.usdc --no-materials
usd-convert-cad -i assembly.step -o assembly.usdc --filter-style hide --convert-metadata

Shell Invocation

The usd-convert-cad console command (and the equivalent python -m usd_convert_cad) is the public cross-platform entrypoint. It runs from PowerShell, cmd.exe, bash, or other shells as long as the wheel is installed in the active Python 3.12 environment.

When invoking via an external tool runner, capture stdout and stderr together and branch on the exit code. Relative input and output paths are resolved against the caller's working directory.

Converter Options

The wheel builds a converter Parameters object from the CLI flags and converts in one call. Run usd-convert-cad --help for the authoritative list for the installed version. The documented options include:

Implementation Contract

Conversion passes only when the converter returns error_code == 0 and the expected USD output exists. The CLI maps this to process exit code 0 for success and non-zero for failure.

Limitations

Before promising conversion success or diagnosing failures, read ../../LIMITATIONS.md for package limitations and upstream HOOPS Core known issues.

Troubleshooting

Report a blocked conversion when:

• The active Python is not 3.12.
• The usd-convert-cad wheel is not installed (usd-convert-cad --help fails).
• The source file extension is not listed under Supported Formats.
• The input is an AutoCAD (.dwg, .dxf) or Revit (.rvt, .rfa) file and the platform is linux-aarch64 — these formats are not supported there (see Platform Support). Report the platform limitation rather than retrying.
• The converter returns a non-zero exit code or does not produce the expected output.

References

• docs/concept_mapping.md for HOOPS Exchange to OpenUSD concept mapping.
• LIMITATIONS.md for detailed known limitations and upstream known-issues reference.
• README.md for repository overview and user-facing setup notes.
• CONTRIBUTING.md for maintainer expectations and supported-format update policy.
• usd-convert-cad --help for the authoritative converter option list of the installed wheel.