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Getting Started

This page guides you through the process of building Momentum (C++ library) and running the examples.

Installing Momentum​

Momentum C++ binary builds are available for Windows, macOS, and Linux via Pixi or the Conda package manager.

For Windows, please install Visual Studio 2022 or greater.

Pixi​

pixi add momentum-cpp

Conda​

conda install -c conda-forge momentum-cpp

Building Momentum from Source​

Prerequisite​

Complete the following steps only once:

  1. Install Pixi by following the instructions on https://prefix.dev/

  2. Clone the repository and navigate to the root directory:

    git clone https://github.com/facebookresearch/momentum
    cd momentum

    Ensure that all subsequent commands are executed in the project's root directory unless specified otherwise.

Build and Test​

  • Build the project with the following command (note that the first run may take a few minutes as it installs all dependencies):

    pixi run build

  • Run the tests with:

    pixi run test

To view all available command lines, run pixi task list.

Hello World Example​

To run the hello_world example:

pixi run hello_world

Alternatively, you can directly run the executable:

# Linux and macOS
./build/hello_world

# Windows
./build/Release/hello_world.exe

Running Other Examples​

To run other examples:

pixi run glb_viewer --help

For more examples, please refer to the Examples page.

Clean Up​

If you need to start over for any reason:

pixi run clean

Momentum uses the build/ directory for CMake builds, and .pixi/ for the Pixi virtual environment. You can clean up everything by either manually removing these directories or by running the command above.

FBX Support​

Momentum uses OpenFBX to load Autodesk's FBX file format, which is enabled by default. To save files in FBX format, you must install the FBX SDK 2020.3.

Linux​

The FBX SDK will be automatically installed when you run pixi run config, so no additional steps are required.

macOS and Windows​

You can download it from Autodesk's website or use direct links (macOS, Windows). After installing the SDK, build Momentum from source with MOMENTUM_BUILD_WITH_FBXSDK=ON option as:

# macOS
MOMENTUM_BUILD_WITH_FBXSDK=ON pixi run <target>

# Windows (Powershell)
$env:MOMENTUM_BUILD_WITH_FBXSDK = "ON"; pixi run <target>

# Windows (cmd)
set MOMENTUM_BUILD_WITH_FBXSDK=ON && pixi run <target>

For example, file conversion can be run as follows:

# Windows (Powershell)
$env:MOMENTUM_BUILD_WITH_FBXSDK = "ON"; pixi run convert_model -d <input.glb> -o <out.fbx>