Tiny, dependency-free USDZ loader library in C++11

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updateLast update 2020-12-18

Tiny USDZ loader

TinyUSDZ is dependency-free(depends only on C++ STL. Yes, you don't need USD library!) USDZ loader library written in C++11.


TinyUSDZ is currently in alpha stage. Not usable.

  • USDC data parse
  • Reconstuct primitive and scene graph representaion(2020 Fall expected)
    • GeomMesh
    • GeomBasisCurves(for hair/fur)
    • GeomPoints(for particles)
    • Xform
    • etc.
  • Write simple SDL viewer example(2020 Winter expected)
  • Character animation(usdSkel) support(2020 Winter expected)
  • Vulkan raytracing viewer example
  • Viewer with Metal ray tracing API?
  • USDZ(USDC) writer


TinyUSDZ does not support Reality Composer file format(.reality) since it uses proprietary file format and we cannot understand it(so no conversion support from/to Reality also).

Other related projects

Supported platforms

  • Linux 64bit or later
    • ARM AARCH64
    • x86-64
    • RISC-V(Should work)
    • SPARC, POWER(Big endian machine). May work(theoretically)
  • Android arm64v8a
  • iOS(Should work)
  • macOS
  • Windows 10 64bit or later
    • Windows ARM(should work)


  • C++11 compiler
    • gcc 4.8.5(CentOS 7 default) or later
    • Visual Studio 2017 or later(2015 may OK)
      • Can be compiled with standalone MSVC compilers(Build Tools for Visual Studio 2017)
    • clang 3.8 or later
    • llvm-ming(clang) supported

USDZ file format

USDZ is actually the uncompressed zip file. USDZ(ZIP) contains usdc(binary) and resources(e.g. image/auduo files)

Security and memory budget

USDZ(USDC) is a binary format and data are compressed. To avoid out-of-bounds access, out-of-memory, and other security issues when loading malcious USDZ(e.g. USDZ file from unknown origin), TinyUSDZ has a memory budget feature to avoid out-of-memory issue.

To limit a memory usage when loading USDZ file, Please set a value max_memory_limit_in_mb in USDLoadOptions.

TinyUSDZ source codes are also checked by Address Sanitizer, CodeQL and Fuzzer.


Integrate to your app

Recomended way is simply copy src and include folder to your app, and add *.cc files to your app's build system.

I do not recommend to use tinyusdz as a git submodule, since the repo contains lots of codes required to build TinyUSDZ examples but these are not required for your app.

Compiler defines

  • TINYUSDZ_USE_OPENSUBDIV : Use OpenSubviv for subdivision surface(to get smooth mesh from USD(Z) primitive). Default enabled.


cmake build is still provided for CI build. CMakeSettings.json is provided for Visual Studio 2019.

Cmake project is not recommended for embedding TinyUSDZ to your app.

$ mkdir build
$ cd build
$ cmake ..
$ make

LLVM-MinGW build

MinGW native and cross-compiling example using llvm-mingw(clang) is provided. See scripts/bootstrap-cmake-mingw-win.sh and scripts/bootstrap-cmake-llvm-mingw-cross.sh for details.

One of benefit to use llvm-mingw is address sanitizer support on Windows app.

To run app(.exe, you'll need libunwind.dll and libc++.dll on your working directory or search path)

For Windows native build, we assume ninja.exe is installed on your system(You can use it from Meson package)

CMake build options

  • TINYUSDZ_BUILD_TESTS : Build tests
  • TINYUSDZ_BUILD_EXAMPLES : Build examples(note that not all examples in examples folder are built)
  • TINYUSDZ_WITH_OPENSUBDIV : Use OpenSubviv to tessellate subdivision surface.
    • OpenSubdiv code is included in TinyUSDZ repo. If you want to use external OpenSubdiv repo, specity the path to OpenSubdiv using osd_DIR cmake environment variable.
  • TINYUSDZ_WITH_AUDIO : Support loading audio(mp3 and wav).
  • TINYUSDZ_WITH_EXR : Support loading EXR format HDR texture through TinyEXR.

clang-cl on Windows

Assume ninja.exe is installed and path to ninja.exe is added to your %PATH%

Edit path to MSVC SDK and Windows SDK in bootstrap-clang-cl-win64.bat, then

> bootstrap-clang-cl-win64.bat
> ninja.exe


Meson build is provided for compile tests.

$ meson builddir
$ cd builddir
$ ninja


See examples directory for more examples.

Data format

See preview_surface.md


  • Support Crate(binary) version 0.8.0(USD v20.11 default)
  • Write parser based on the schema definition.
  • Subdivision surface using OpenSubdiv.
    • Build TinyUSDZ with OpenSubdiv(CPU)
    • Replace OpenSubdiv with our own subdiv library or embree3's one.
  • USDA(USD Ascii) support
    • Write our own USDA parser with PEG.
    • USDA writer.
  • Animation
    • Skinning(usdSkel)
    • Blend shapes
      • In-between blend shapes
  • Audio play support
    • Play audio using SoLoud or miniaudio(or Oboe for Android)
    • wav(dr_wav)
    • mp3(dr_mp3)
    • m4a?
  • Support AR related schema(Game-like feature added by Reality Composer?)
  • Android example
  • iOS example?
  • CPU raytracer viewer
    • sdlviewer
  • Viewer with Vulkan API.
  • Read USD data with bounded memory size. This feature is especially useful for mobile platform(e.g. in terms of security, memory consumption, etc)
  • USDZ saver
  • Support Nested USDZ
  • UDIM texture support
  • Support big endian architecture.

Fuzzing test

See tests/fuzzer/


TinyUSDZ is licensed under MIT license.

Third party licenses