How to get that plugin enabled?


I tried to go step-by-step like in the tutorial here:
YouTube watch?v=Y9XPCKQBg8E&t=914s

I expected to see NVidia RTX Global Illumination plugin, but I don’t see it here.

Steps I made:

  1. Downloaded the source code of Unreal from that branch:
    Github NvRTX UnrealEngine
    Branch: nvrtx-5.1
  2. Build it via MS VS 2022 Community Edition
  3. Started from Binary folder
  4. I see no plugin in my plugin list

Could you help me to enable that plugin?

I would like to use VVGI Volume with probes

And a side question: what’s difference between RTXGI and RTXDI?

Thank you!

I see no plugin with Global Illumination in the list

Hi there @serge.almazov and welcome to the NVIDIA developer forums!

Great to see that you are interested in NvRTX!

I recommend reading through the RTXDI documentation which is part of the NvRTX branch to get started.

To properly understand the difference between RTX Global Illumination and RTX Direct illumination, watch the other on-demand videos on the topics in out developer only area.

I a nutshell, RTX Global Illumination is the ray-traced effect if indirect lighting through global light-sources in a scene, while direct illumination is concerned with the direct effect of light-sources in the scene. Think about the ambient light outside a house that refracts through windows, reflects from walls and furniture, changes color when shining through leaves on trees, etc. That is GI. Then imagine a desk lamp on a table shining on a book. That is direct illumination.

Lastly, the idea of the NvRTX branch is to integrate our tech into the Unreal Engine code, which means there will be no need for the DI plugin. See for example

The RTXGI plugin was put on hold for the time being with UE 5.0, since Lumen does a very similar job in that regard.

I hope this helps!

Thank you very much, MarkusHoho!

I read a documentation page you provided. Am I understood correctly that (according the documentation):
Instead of using volumes I can enable Direct Illumination (DI) via setting the parameter
r.RayTracing.SampledLighting to 1


I will check the video on demand as well.

I have 2 questions:

  1. How to enable RTXGI in Unreal 5.1?
  2. And a question about your branch with caustics. Why do you need a separate branch for it? :)

I am not the expert in RTXDI, but maybe @rcowgill can answer your first question on Volumes vs SampleLighting.

Regarding RTXGI, the latest UE version we officially support with a plugin is 4.72. If you still want to use it you need to familiarize yourself with the official RTXGI SDK and integrate that into your project.

Why the Caustics branch differs from NvRTX main is something I do not know.

Hi, I really want to understand how it works.
For example I made that scene and put some basic objects and basic lightning like direct lightning and spotslight

And that screenshot I made with r.RayTracing.SampledLighting to 1

Tried to find something like denoiser volume actor, but didn’t wok for me.

So I’m curious about the process of using it. And previously there were some volume actors in Unreal. Did something change for now? How to work with probes?

@rcowgill , do you know what’s the difference between using Volumes and SampleLighting? :)

Hi @serge.almazov,

I am “just” a community manager, meaning I do have a wide range of expertise, but when it comes to deeper questions, I need to refer to the experts. And as it so happens, the experts actually have a day job which is not directly connected to forums and they are pretty busy.

That is why it can take a while until one of those experts jumps in to give feedback.

And if you need my attention, feel free to tag me in the original post, not in some other persons post. It is kind of bad style :-)


Thank you, @MarkusHoHo !

Didn’t know you are guys so busy :)