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RTX Global Illumination

Leveraging the power of ray tracing, the RTX Global Illumination (RTXGI) SDK provides scalable solutions to compute multi-bounce indirect lighting without bake times, light leaks, or expensive per-frame costs. RTXGI is supported on any DXR-enabled GPU, and is an ideal starting point to bring the benefits of ray tracing to your existing tools, knowledge, and capabilities.


Access RTXGI   Introductory Resources

RTXGI on and off comparison

RTXGI enabled in Portal With RTX.

Dynamic Scenes With RTXGI


Neural Radiance Cache (NRC) is an AI-powered algorithm that trains the radiance cache about a scene in real time, handling fully dynamic scenes with no assumptions about lighting, geometry, and materials. It uses AI acceleration to train the radiance cache in real time to offer improved performance and more accurate global illumination in highly demanding scenes.

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This slider shows the raw denoised cache visualization with NRC off and on. NRC enabled significantly enhances the signal quality of the radiance data.

Spatial Hash Radiance Cache (SHaRC) is a radiance cache that's built on a spatial hash data structure designed for a fast and scalable global illumination technique for path tracing. It's similar to NRC, but it doesn't use a neural network. SHaRC will run on any DirectX or Vulkan ray-tracing-capable GPU.

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This slider shows SHaRC featured in Cyberpunk 2077. With SHaRC enabled, the GI lighting is able to cover more of the scene with negligible performance impact.

Content creation at the speed of light. Accelerated global illumination in path tracing. Infinite bounce lighting in real time. Dynamic Diffuse Global Illumination (DDGI) provides a scalable probe-based solution to deliver multi-bounce indirect lighting without requiring any offline lightmaps or light baking.

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This slider shows DDGI in an Unreal Engine powered museum scene. Here the enhanced realism of the indirect lighting from DDGI allows greater detail to be visible in the scene.

RTXGI Product Features


Accelerated Global Illumination Solutions for Real Time Path Tracing

With RTXGI, you can leverage fast and efficient radiance caching techniques to deliver optimal performance for the most demanding graphical applications. The solutions cover any ray-tracing-capable GPU with standard and AI-accelerated algorithms leveraging the increased capability of NVIDIA tensor cores.

RTXGI in museum scene
RTXGI’s scalable design shown in forest scene

One Scalable Solution for All

Full source code puts you in control. Customize RTXGI to your needs on any DXR-enabled GPU. RTXGI's scalable design gives you the control to decide when and where you want to crank up performance or max out image quality.

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FAQ

A: RTXGI is a software development kit that leverages the power of GPU ray tracing to provide scalable solutions for the computation of global illumination in real-time graphics applications.
A: Version 2.0 adds two new radiance caching algorithms to enable fast and accurate diffuse global illumination solutions for realtime path tracing: Neural Radiance Cache (NRC) and Spatial Hash Radiance Cache (SHaRC).
A: Yes! The ability to trace arbitrary rays is an essential component that enables the flexibly to dynamically update lighting information at runtime.
A: Unlike existing real-time global illumination solutions, RTXGI uses real-time ray tracing to dynamically update lighting information - eliminating the need for pre-computation or baking steps.
A: The RTXGI SDK is a full source distribution. The SDK includes the complete C++ and HLSL source code of the SDK libraries (DDGI, NRC, and SHaRC), and UE4 plugin, as well as documentation for the SDK code and UE4 plugin. A full-source sample application that demonstrates how to use the SDK is also included.
A: DDGI is a probe-based indirect diffuse illumination technique that is scalable across GPUs. NRC is an AI-powered algorithm that trains the radiance cache about a scene in real time, handling fully dynamic scenes with no assumptions about lighting, geometry, and materials. SHaRC is a radiance cache that's built on a spatial hash data structure. It's similar to NRC, but it doesn't use a neural network.
A: DDGI is built to provide efficient indirect lighting across a wide range of GPUs. NRC is built to take advantage of Tensor Cores in RTX GPUs and provide the highest quality and performing indirect lighting solution for path-traced engines. SHaRC is a scalable non-neural fallback option to NRC that'll run on non-NV gpus.
Yes. DDGI is now available as a plug-in for Unreal Engine 4.27 and UE5.0. However, there's no RTXGI UE plugin support for version later than UE5.0. Also, note that NRC and SHaRC haven't been integrated into Unreal Engine yet.
A: We are working closely with Unity to bring RTXGI support to their engine as soon as possible. Stay tuned!
A: The RTXGI SDK supports the DirectX Raytracing (DXR) API on Windows and Vulkan Ray Tracing API on Windows and Linux.
A: The RTXGI SDK supports x86-64 on Windows and x86-64 and ARM64 architectures on Linux.
A: DDGI and SHaRC work with any DXR-enabled GPU. NRC uses the tensor cores featured on NVIDIA GPUs starting with 20 Series and later.
A: The RTXGI SDK is now available publicly via our GitHub source repo. The RTXGI UE4/UE5 plugin is pre-installed in the NVIDIA RTX branch and is also available as a binary plugin on the UE4 marketplace.
A: Yes. We encourage students and academics of all kinds to explore what RTXGI makes possible.

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