Local Development#

This guide covers the two ways to build an application against ovphysx, plus the Python wheel workflow for rapid iteration.

Building Against the Installed SDK#

The simplest approach: build ovphysx once, install it, and point your app at the install tree with find_package().

# 1. Build ovphysx (fetches dependencies automatically)
cd omni/ovphysx
./build.sh            # Linux
build.bat             # Windows

# 2. Install the SDK into _install/
cmake --build _build --target install_sdk

# 3. Build your app against the installed SDK
cmake -S my_app -B my_app/_build \
    -DCMAKE_PREFIX_PATH="$(pwd)/_install"
cmake --build my_app/_build

Your app’s CMakeLists.txt uses find_package():

find_package(ovphysx REQUIRED)
target_link_libraries(my_app PRIVATE ovphysx::ovphysx)

See tests/c_samples/hello_world_c/ for a complete example.

Building Against the Source Checkout#

If you need to iterate on ovphysx code and have your app automatically recompile changed sources, use add_subdirectory() instead.

# No prior build step needed — dependencies are fetched at configure time.
cmake -S my_app -B my_app/_build
cmake --build my_app/_build

Your app’s CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)
project(my_app C CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_POSITION_INDEPENDENT_CODE ON)

# Point at the ovphysx source tree
set(OVPHYSX_SOURCE_DIR "/path/to/omni/ovphysx")
add_subdirectory("${OVPHYSX_SOURCE_DIR}" "${CMAKE_BINARY_DIR}/ovphysx")

add_executable(my_app main.c)
target_link_libraries(my_app PRIVATE ovphysx::ovphysx)

# Set up RPATH / DLL copying so the executable finds libraries at runtime
ovphysx_setup_source_link_runtime(my_app)

The first cmake configure will automatically fetch packman dependencies (controlled by OVPHYSX_FETCH_DEPS, default ON). Subsequent configures skip the fetch if the dependencies already exist.

Edit-rebuild cycle:

# Edit ovphysx source.
vim omni/ovphysx/src/ovphysx/ovphysx.cpp

# Rebuild — only changed ovphysx sources recompile
cmake --build my_app/_build

ovphysx_setup_source_link_runtime() configures RPATH (Linux) or copies DLLs (Windows) so that the executable can load libovphysx.so and its direct dependencies.

Running the executable: The ovphysx runtime also needs Carbonite and PhysX plugins at runtime (loaded through dlopen). The simplest approach is to build the installed SDK once and point OVPHYSX_LIB at the installed ovphysx library so the runtime can derive the matching config, schema, and plugin paths:

# One-time setup: build and install the SDK
cd omni/ovphysx && ./build.sh && cmake --build _build --target install_sdk

# Run with runtime layout from the installed SDK
OVPHYSX_LIB=omni/ovphysx/_install/lib/libovphysx.so ./my_app/_build/my_app

On Windows, use OVPHYSX_LIB=omni\ovphysx\_install\bin\ovphysx.dll.

See tests/c_samples/hello_world_source_link/ for a complete example.

Python Wheel Workflow#

For Python users, the ovphysx wheel contains the physics runtime plus the OVStage-provided OmniClient and connection libraries needed for PhysX-first startup. It declares an exact ovstage wheel dependency, which supplies the matched OVStage runtime, USD resolver and registry, and namespaced USD runtime without packaging duplicate resolver/USD singletons in the ovphysx wheel.

cd omni/ovphysx

# Build everything and create the wheel in _dist/
./build.sh
cmake --build _build --target build_wheel

# Install into a virtual environment
uv pip install _dist/ovphysx-*.whl

For fast iteration without rebuilding the wheel, point OVPHYSX_LIB at the build tree:

export OVPHYSX_LIB="$(pwd)/_build/linux-x86_64/release/libovphysx.so"
python my_script.py

Configuration Reference#

CMake Cache Variables#

Variable	Default	Description
`OVPHYSX_FETCH_DEPS`	`ON`	Automatically fetch packman dependencies at configure time
`LOCAL_TARGET_DEPS`	`<ovphysx>/_build/target-deps`	Override the directory where packman dependencies are stored
`OVPHYSX_DEV_PHYSX`	`OFF`	Build PhysX SDK from source instead of using prebuilt binaries
`OVPHYSX_DEV_SCHEMA`	`OFF`	Use locally-built physics schema
`OVPHYSX_WARNINGS_AS_ERRORS`	`ON` in CI, `OFF` otherwise	Treat compiler warnings as errors
`OVPHYSX_BIN_DIR`	(empty)	Advanced build-time helper path for Kit/PhysX plugin linkage; not a runtime environment variable

Environment Variables#

Variable	Description
`OVPHYSX_LIB`	Path to `libovphysx.so` / `ovphysx.dll`. Python loads this library directly; native/source-link runs use its directory to find `config.toml`, plugins, and USD schema paths.