460.89 Studio and Game Ready driver regression; issues with UE4 4.25 Niagra transparent particles with ray tracing

Visual, Game & Mobile Development DirectX and Direct Compute
#1

Upgraded to the latest studio driver (from 457.30 to 460.89). We noticed a Niagra fire particle no longer shows up properly when ray tracing is enabled. When ray traced translucency is disabled, rasterization renders properly.

457.30 Studio Driver - renders as intended
460.89 Studio Driver - initial issue found (incorrectly rendering)

457.51 Game Ready Driver - renders as intended
460.79 Game Ready Driver - incorrectly rendering
460.89 Game Ready Driver - incorrectly rendering
460.97 Game Ready Driver hotfix - incorrectly rendering

Hardware tested on:
RTX 3090
i9 9900k
Win 10 Pro 20H2

Screenshots attached. Let me know what other information you need to help figure this out.

Thanks,
Cameron

Edit: looks like I can’t add more than 1 image, so here is a dropbox link: https://www.dropbox.com/sh/g5pnfxo4pv7wto5/AAASNTo6FbgEefSQ5koDfJ-Ia?dl=0

#2

Hi Cameron, is it possible we could get this niagara fire particle asset for testing? Ideally an isolated test map/test project if you have it. Thanks

#3

Do you have access to the Unreal Developer Network? I posted additional info including a test project there. https://udn.unrealengine.com/s/question/0D52L000055Mdp0SAC/46089-studio-and-game-ready-driver-regression-issues-with-ue4-425-niagra-transparent-particles-with-ray-tracing

Pertinent info:
I can confirm the issue does not exist in 457.51. Newer drivers produce the issue in 4.25, but not 4.26 (4.26 renders correctly).

Unfortunately we can’t upgrade all our projects to 4.26 right now, so we’re stuck on 457.51 for a little while longer. If you have a code fix that we can apply to our 4.25 code base, that would be great.

Attached is a test project. Let me know how else I can help.

NiagraTest425.zip (5.2 MB)

#4

That should be everything we need thank you! I don’t have access to the developer network, but I did just download the attached test project. We’ll check things out and hopefully have some answers for you. Thanks again!

Richard