LightUSD

LightUSD is a full-featured, dependency-free, lightweight USD library written in C++17. It reads and writes USDA, USDC, and USDZ, and includes MaterialX and USD Physics support. (Previously known as TinyUSDZ)

The src/next product is the default for native, Python, and WASM consumers. The legacy product is deprecated, but remains in the repository and in CI for existing integrations. Select it explicitly with -DLIGHTUSD_NATIVE_PRODUCT=legacy or -DLIGHTUSD_WASM_PRODUCT=legacy.

LightUSD is designed for applications that need USD to be compact, portable, and fast: high-performance 3D interchange and DCC tools, render and asset pipelines, generative AI, and Physical AI systems that connect scene understanding with simulation and robotics. The same core runs across desktop, mobile, WebAssembly, and sandboxed environments, with explicit resource limits for untrusted assets. MCP interface provided.

Releases

• v1.0.0 (26.11)
  • First stable release.
  • Add Lean formalization of the USD (AOUSD Core) spec: https://usdspec-conformance.lighttransport.workers.dev/

Packages

Python:

python -m pip install lightusd

import lightusd

stage = lightusd.load("scene.usdz")
for prim in lightusd.traverse(stage):
    print(prim.type_name, prim.name)

See python/README.md for Python usage. WebAssembly and JavaScript packages live under web/.

Build

LightUSD requires a C++17 compiler and normally uses CMake:

cmake -S . -B build_ninja -G Ninja \
  -DLIGHTUSD_BUILD_TESTS=ON -DLIGHTUSD_BUILD_EXAMPLES=ON
cmake --build build_ninja
ctest --test-dir build_ninja --output-on-failure

See doc/build-and-examples.md for integration, build options, and examples.

Documentation

• Documentation index
• API and schema status
• MaterialX
• USD Physics
• Composition
• Python bindings
• AOUSD conformance — LightUSD verification against the AOUSD Core Specification v1.1.0 (v1.0.1 plan + v1.1 delta audit)
• Testing
• Release and CI

Security

Use USDLoadOptions::max_memory_limit_in_mb for unknown inputs. For hostile or internet-sourced assets, also isolate loading in a sandboxed process or WASI environment.

License

LightUSD is primarily licensed under Apache 2.0. Some helper code uses MIT or similarly permissive licenses. See LICENSE.3rdparty for third-party notices.