New GPUs and RTXGI

Development Rendering
1

Hi!

With the upcoming of new generation of GPUs is it posible we can expect a better implentation of RTXGI in 4.26?

Something like this would be neat:

The current implementation is too expensive and having the probes may even allow for slow updating of the probes using CPU ray tracing, or no updating at all but having a workflow that would allow for static GI with no lightmap UV authoring and open world scenarios.

My wild guess is that most of it is already implemented in the engine as the current RTX implementation is tracing the rays and shading the results. Nvidia showcased a version of UE4 running this here:

2

I mean that’s really up to nvidia isn’t it? Epic doesn’t have an implementation of RTXGI, all of that is in nvidia’s branch.

3

I’m not sure. There is a more brute force approach to RTXGI in UE4 already implemented. Nvidias branch is public as far as I know.

http://​​​​​​​https://docs.nvidia.com/rtx-dev-ue4/intro-relnotes/index.html

I remember watching the GDC presentation that they stated somewhere that there is no SDKs or patents for the algorithm.

4

That is not RTXGI. Unreal’s raytracing implementation is via DXR.

No idea if that is true but I believe Epic is intentionally seeking vendor agnostic solutions.

I don’t know what epic has planned for raytracing but I suspect Lumen is probably the future for realtime GI in UE4. At least for the near term.

5

Then I guess waiting for lumen and hacking whatever sky occlussion solution I can is gonna have to cut it.