Unreal RTXDI NRD Texture Blurring

Hello

I’ve been testing the latest UE nvrtx 5.3.2 build, and noticed significant blurring of high frequency texture detail and even cast shadows in certain cases. I imported a few nanite megascan assets into Unreal to demonstrate what happens when Sampled Lighting (with NRD Relax) is turned on:

NRDRELAX1
NRDRELAX2
NRDRELAX3

I have also tried the latest build with ReSTIR GI (April 23rd), and tested CVARS such as:

r.RayTracing.SampledLighting.Temporal.ApplySpatialHash r.RayTracing.SampledLighting.DemodulateMaterials r.RayTracing.SampledLighting.Spatial.Samples
r.NRD.Relax.DI.Atrous.Iterations
r.NRD.Relax.DI.DenoisingRange

Setting Spatial Hash/Atrous Iterations to 0, or upping spatial samples (without the denoiser) can work in some cases, but it’s not ideal for large scenes.

I was wondering if there are any specific settings that can be used to make sure that high frequency detail is preserved with the Relax denoiser?

Thank You

More tests with a larger set, Sampled Lighting 0/1, NRD Technique set to ReLAX:

CaveComparisonGIF

The Sampled Lighting mode is definitely more accurate, but the NRD ReLAX denoiser seems to blur textures, lighting information, and distant geometry detail.

I also tested the RTXDI sample that’s included with the NVRTX build, and added a simple megascan normal map to the box geometry:
RTXDI_Test

It’s possible to get rid of some of the flickering by increasing spatial and brdf samples, but the blur definitely affects the normal map texture, and the overall sharpness of the final image. Same render without the light geo in the viewport:

Going back to the original question, is this the expected functionality of using RTXDI with NRD? Is it possible to preserve texture and geometry detail with certain CVARS that are not activated when Sampled Lighting is turned on?

Having gone through both the RTXDI and NRD docs, I didn’t notice anything that mentioned these issues specifically, but it would be really good to update those readme’s for users.