RTX Global Illumination
RTX Global Illumination (RTXGI)
Leveraging the power of ray tracing, the RTX Global Illumination 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.
Full Source Code
We are providing full source code so you can easily integrate RTXGI into your tools and customize it to your specific needs.
No Baking, No Leaks
No more waiting for bakes. Dramatically speed up your iteration time with real-time ray traced lighting. No more obsessing over light probe positioning either; no light or shadow leaking.
Any DXR GPU
RTXGI runs on a broad range of platforms. All DXR-enabled GPUs are supported, including the GTX 10 series (Pascal).
Tuned & Optimized
Easy to integrate and fast to provide results, right out of the box. Performance optimized to fit in 60Hz frame budgets.
Accelerated by Ampere
Get the most out of the new RTX 3000 series GPUs with RTXGI
The RTX 3080 delivers a 2x increase in RTXGI samples-per-millisecond compared to the RTX 2080 S, and a nearly 7x boost compared to GTX 1080 Ti.
RTXGI 1.1 Features
Regularly spaced probe grids are not able to handle every scene without (at least) minor visual artifacts and inefficiencies. To mitigate this problem, the RTXGI SDK includes a feature that moves (or relocates) the world-space position of probes to improve their effectiveness and eliminate situations that cause visual problems. This feature was released in beta form in the previous release, and is now leaving beta as a finalized feature. The effectiveness and stability of the relocation behavior have been improved and are now production ready.
By default, all probes in a volume cast new rays, update their stored values, and can be used to compute global illumination. Probe classification identifies and disables probes that don’t contribute meaningfully to the final result, saving computation and improving performance. This feature was released in beta form in the previous release, and is now leaving beta as a finalized feature. The way probes are classified has been improved, is easier to use, and can produce more effective optimizations.
Multiple Volume Blending
When using RTXGI volumes in game scenes, there are situations where multiple volumes are needed. These volumes may overlap. For these situations, the SDK now provides a scheme and example of how to weigh and blend the contributions of multiple volumes for a space in the game world.
With the latest update, you can increase lighting quality and decrease memory use by rotating RTXGI volumes to tightly fit your content. In UE4, use the standard translation and rotation gizmos to align the RTXGI volume and you are good to go.
Infinite Scrolling Volumes (beta)
A common use case of RTXGI is to attach and center a single volume to a player or camera, and then update the volume as the player moves. This effectively provides an "infinite" volume of global illumination for the player without needing large amounts of memory to store an infinite number of probes. In practice though, simply moving the volume at the same rate as the player causes visual artifacts. With the new infinite scrolling volumes feature, the majority of the volume's probes remain stationary, and only probes on the edges of the volume are shifted during player movement. By minimizing the amount of change to probes, this feature creates more stable lighting results when moving a volume.
Plug It In
RTXGI 1.1 is now available in Unreal Engine 4 through our official RTXGI UE4 plugin. With the RTXGI UE4 plugin, Unreal Engine 4 developers can benefit from the fast, dynamic ray traced global illumination provided by RTXGI. Dramatically speed up your content creation pipeline and enjoy real-time infinite bounce indirect lighting in your UE4 game today.
Flexible, Full Source
The RTXGI UE4 plugin supports Unreal Engine 4.25 and 4.26, in both mainline UE4 and the NVIDIA RTX branch of UE4. The RTXGI plugin now comes pre-installed in the NVIDIA RTX branch. Just like the core SDK, the UE4 plugin is distributed with full source code, so you can modify the plugin to fit your specific needs. Instructions on how to install and use the plugin are included in GitHub. Get started today!
Infinite Bounce Lighting in Real Time
Fast multi-bounce indirect lighting has never been easier.
RTXGI's probe-based data structure temporally accumulates and filters lighting and distance information in real time, creating a high quality multi-bounce lighting cache with visibility information.
Strict frame budget? RTXGI provides an ideal balance between quality and performance for real-time applications with tight frame budgets through a low frequency approximation of the full path tracing process.
Content Creation at the Speed of Light
Accelerate your tools, pipeline, and artist workflows.
With RTXGI, the long waits for offline lightmap and light probe baking are a thing of the past. Artists get instant results in-editor or in-game. Move an object or a light, and global illumination updates in real time.
Decrease iteration times by cutting out time spent tuning light probe positions. No light or shadow leaking, right out of the box, without obsessing over probe placements.
One Scalable Solution for All
Full source code puts you in control.
Customize RTXGI to your needs on any DXR-enabled GPU, including the GeForce RTX 30 series, RTX 20 Series, GTX 1660 Series, and GTX 10 series. RTXGI's scalable design gives you the control to decide when and where you want to crank up performance or max out image quality.
How It Works
- Fully managed data structure that supports any material and lighting model
- Optimized memory layout and compute shaders
- Support for multiple coordinate systems
- Hooks for engine and gameplay events to prioritize lighting updates
- Real-time lighting updates in-game and in-editor
- Real-time diffuse and glossy indirect without shadow leaks or light leaks
- Infinite bounce global illumination
- No UV parameterization or probe blockers needed
- Optional overrides for automatic probe placement and self-shadow prevention
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: 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 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: Yes! RTXGI is now available as a plugin for Unreal Engine 4.25 and 4.26. RTXGI also comes pre-installed in the NVIDIA RTX branch of UE4.
A: We are working closely with Unity to bring RTXGI support to their engine as soon as possible. Stay tuned!
A: The RTXGI SDK and RTXGI UE4 plugin support the DirectX Raytracing (DXR) API for DirectX12 on Windows.
A: RTXGI works with any DXR enabled GPU. This includes all NVIDIA RTX 30 series, RTX 20 series, GTX 1660 series, and GTX 10 series products.
A: Yes! We encourage students and academics of all kinds to explore what RTXGI makes possible.
Ready to get started developing with RTXGI?