NVIDIA Falcor

Falcor is NVIDIA's open-source real-time rendering research framework, developed by the company's real-time rendering research group. It has become the de facto standard framework for academic and industrial ray tracing research on NVIDIA GPUs, powering landmark publications including ReSTIR (spatiotemporal reservoir sampling), RTXDI (real-time direct illumination), NRD (NVIDIA Real-time Denoisers), and numerous SIGGRAPH papers. Falcor is built primarily on DirectX 12 with DXR ray tracing as a first-class feature, with growing Vulkan support.

Falcor's architecture centers on a render graph system that allows researchers to compose complex multi-pass rendering pipelines from modular render passes. This graph-based approach enables rapid prototyping: new rendering algorithms can be implemented as isolated passes and plugged into existing pipelines without understanding the full framework. The engine ships with reference implementations of path tracers, temporal denoisers, and various GI algorithms that serve as baselines for research comparisons.

A key differentiator is Python scripting via pybind11, enabling automated experiment pipelines — researchers can script scene loading, parameter sweeps, image capture, and metric computation without recompiling C++. Falcor uses Slang as its shading language, supporting advanced features like differentiable shading and generics. The material system supports measured BSDFs, and the scene description system can import PBRT, glTF, USD, OBJ, and FBX formats, enabling direct comparison with physically based rendering literature. While Falcor provides a built-in scene editor with material editing, light placement, and camera controls, it is not a game engine — there is no physics, audio, or networking.