ovx-mockup

Interactive rigid-body physics simulation driving GPU ray-traced rendering. Uses ovphysx for CPU-mode physics and ovrtx for RTX rendering, connected through their shared DLPack tensor interface.

Each frame:

1. A heavy dynamic capsule is driven back and forth by a velocity write.
2. ovphysx_step simulates contacts with the lighter dynamic objects.
3. World-space poses are read back via ovphysx_read_tensor_binding.
4. Poses are pushed into the renderer via ovrtx_set_xform_pos_rot_scale.
5. ovrtx_step + Vulkan/CUDA interop presents the frame.

Prerequisites

• NVIDIA RTX GPU with a recent driver
• CUDA Toolkit 12.x
• Vulkan SDK (provides glslc)
• CMake 3.18+
• C++17 compiler (GCC 11+ / MSVC 2019+)
• Git

Getting ovphysx

Download the pre-built tarball for your platform from the NVIDIA-Omniverse/PhysX releases page and extract it somewhere convenient, e.g.:

Linux

# Example: ovphysx-linux-x86_64-0.2.8
tar -xf ovphysx-linux-x86_64-0.2.8.tar.gz -C ~/local

Windows

# Example: ovphysx-windows-x86_64-0.2.8
Expand-Archive ovphysx-windows-x86_64-0.2.8.zip -DestinationPath C:\local

Cloning

git clone https://github.com/JohnTwenty/ovx-mockup
cd ovx-mockup
git submodule update --init --depth=1

The submodule (third-party/ovrtx, pinned to v0.2.0) provides two things:

• The cmake module that auto-downloads the ovrtx pre-built binary at configure time.
• The Vulkan/CUDA helper sources shared with the vulkan-interop example.

Getting ovrtx (normally automatic)

The cmake configure step downloads the ovrtx pre-built binary from GitHub Releases automatically into _deps/. No manual step is needed if your machine can reach github.com.

If the download is blocked (corporate proxy, air-gap network): download the zip manually from the ovrtx releases page, extract it, and pass the path with -DOVRTX_DIR=... (see below).

Platform	Package filename
Linux x86_64	ovrtx@0.2.0.manylinux_2_35_x86_64.zip
Linux aarch64	ovrtx@0.2.0.manylinux_2_35_aarch64.zip
Windows x86_64	ovrtx@0.2.0.windows-x86_64.zip

Building

Linux

cmake -B build \
    -DCMAKE_PREFIX_PATH=/path/to/ovphysx-linux-x86_64-0.2.8/ovphysx
cmake --build build --parallel

Windows (Visual Studio)

cmake -B build `
    -DCMAKE_PREFIX_PATH="C:\local\ovphysx-windows-x86_64-0.2.8\ovphysx"
cmake --build build --config Release

Offline / behind a proxy

Pass both package paths so cmake never attempts a network download:

cmake -B build \
    -DCMAKE_PREFIX_PATH=/path/to/ovphysx-linux-x86_64-0.2.8/ovphysx \
    -DOVRTX_DIR=/path/to/ovrtx@0.2.0.manylinux_2_35_x86_64
cmake --build build --parallel

On Windows:

cmake -B build `
    -DCMAKE_PREFIX_PATH="C:\local\ovphysx-windows-x86_64-0.2.8\ovphysx" `
    -DOVRTX_DIR="C:\local\ovrtx@0.2.0.windows-x86_64"
cmake --build build --config Release

-DOVRTX_DIR tells cmake where to find the pre-extracted ovrtx package. ovrtx_fetch() detects it via find_package and skips the download. Other dependencies (glfw3, glm, volk, unordered_dense) are fetched from GitHub at configure time; if those are also blocked, install them via your system package manager or vcpkg and cmake will find them automatically.

Running

./build/ovrtx-interop-physx                  # Linux
.\build\Release\ovrtx-interop-physx.exe      # Windows

The binary expects physics_boxes.usda and compiled shaders in the same directory; CMake post-build commands deploy them automatically.

Optional arguments:

ovrtx-interop-physx [usd_file] [render_product] [up_axis] [duration_s]

Project layout

ovx-mockup/
├── CMakeLists.txt           main build file (~120 lines)
├── src/
│   └── main.cpp             application code (physics + render loop)
├── assets/
│   └── physics_boxes.usda   USD scene (rigid bodies + lights + camera)
└── third-party/
    └── ovrtx/               git submodule @ v0.2.0
        examples/c/
          cmake/ovrtx.cmake  fetches pre-built ovrtx binary
          vulkan-interop/
            shaders/         GLSL sources compiled at build time
            src/             Vulkan/CUDA helpers (referenced, not copied)

The only files this project owns are CMakeLists.txt, src/main.cpp, and assets/physics_boxes.usda. Everything else is either fetched at build time or referenced from the submodule.