usd-experiments

Table of Contents

• Summary
• References
• Getting started

Summary

Experimenting with C++ libraries capable of parsing USD files

References

• USD file format
• OpenUSD Github repository
• tinyusdz Github repository
• OpenUSD - Converting Between Layer Formats
• Download Pre-Built OpenUSD Libraries and Tools
• A really small getting-started project for USD based projects
• OpenUSD sample files for download
• vcpkg issue

Getting started

Preconditions

• Download and install CMake from the official website or trough a package manager
• Install a C++ compiler on your operating system. For example, on Ubuntu Linux use sudo apt install -y build-essential to install the gcc and g++ compilers; on Windows, the cl.exe compiler is included with the Visual Studio IDE; and on macOS, clang and clang++ compilers are system binaries
• Add git submodules: git subdmodule update --init

Generating USDA or USDC files from glTF files

To generate USD files from glTF files, you can either download the pre-built OpenUSD libraries and tools to use the usdcat CLI tool or build the project from GitHub. On macOS 12.0 (Monterey) and later, the pre-built OpenUSD CLI tools, including usdcat, should already be installed. The data folder can be utilized for storing USDA or USDC files. Example usage os usdcat:

usdcat <path to gltf file> -o <path to usd file>
# e.g. usdcat third-party/glTF-Sample-Models/2.0/BrainStem/glTF/BrainStem.gltf -o data/BrainStem.usda
# e.g. usdcat third-party/glTF-Sample-Models/2.0/BrainStem/glTF/BrainStem.gltf -o data/BrainStem.usdc

Building application binaries

Mac OS

Run:

# INFO: Tested on macOS 15
./third-party/vcpkg/bootstrap-vcpkg.sh
./third-party/vcpkg/vcpkg install --allow-unsupported # Initially building USD can be time-consuming and resource-intensive. Packages persist in the vcpkg git submodule
# Unable to use the `-DCMAKE_TOOLCHAIN_FILE` option because of build errors as the `--allow-unsupported` flag is not available in the subsequent `cmake` command
cmake -B build -DCMAKE_BUILD_TYPE=Release .
cmake --build build --parallel --config Release
./build/apps/openusd-parser/openusd-parser <path to USDC or USDA file> <path to output text file>
# e.g. ./build/apps/openusd-parser/openusd-parser data/BrainStem.usdc data/BrainStem.txt

Windows OS

Run:

# INFO: Tested on Windows 10
.\third-party\vcpkg\bootstrap-vcpkg.bat
.\third-party\vcpkg\vcpkg install # Initially building USD can be time-consuming and resource-intensive. Packages persist in the vcpkg git submodule
cmake -B build -DCMAKE_BUILD_TYPE=Release . 
cmake --build build --parallel --config Release
.\build\apps\openusd-parser\Release\openusd-parser <path to USDC or USDA file> <path to output text file>

Linux Ubuntu OS

Run:

# INFO: Tested on Linux Ubuntu 20.04
./third-party/vcpkg/bootstrap-vcpkg.sh
./third-party/vcpkg/vcpkg install # Initially building USD can be time-consuming and resource-intensive. Packages persist in the vcpkg git submodule
cmake -B build -DCMAKE_BUILD_TYPE=Release .
cmake --build build --parallel --config Release
./build/apps/openusd-parser/openusd-parser <path to USDC or USDA file> <path to output text file>