RTXDI + Groom crashing

Hey all,

I’m currently working on a UE5 project and we have decided to switch over to the NvRTX build compiled from source to take advantage of the ray tracing performance increases (particularly when used with an RTX 4090). Very happy in that regard!

However there are some issues I’m running into and the first major one I’m looking for help with is the engine crashing when RTXDI is enabled and I have a groom asset visible.

Here is the error I’m getting:
Assertion failed: Buffer-> Desc.UnderlyingType != FRDGBufferDesc::EUnderlyingType:VertexBuffer [File:F:\nvrtx\UnrealEngine\ Engine\ Source \Runtime RenderCore PubliciR enderGraphResources.in] [Line: 193] VertexBuffer Hair. VisibilityNodeCoord requires a type when creating a SRV.

I’ve tried the following combinations:
Groom ray tracing enabled/disabled + RTXDI disabled = works
Groom ray tracing enabled/disabled + RTXDI enabled = crashes

I’ve also tried the combinations above with the cvar
r.RayTracing.SampledLighting.Hair 1
and get the same crash.

At the moment the workaround is that I’m just not using RTXDI but would very much like to enable it!!

Any help would be much apricated, thanks!

For reference, I’m able to replicate this bug by opening up the RTXDI sample project and importing a metahuman, same error resulting in a crash.

Just tried with the latest 5.1 build and still having the same crash. I can have a groom in the level with sampled lighting turned on, but the groom is dark and not receiving any lighting.

As soon as I set: r.RayTracing.SampledLighting.Hair 1

It crashes :'(

Hello @john212 !

My apologies that this post got overlooked for so long.

Would you be able to share debug logs with the NvRTX logging enabled when it crashes?

I’ll see if I can get someone from engineering to look at it.


Hello, I am facing the same issue a long time ago. I would like to know how to fix this problem if possible. Thanks!

Just downloaded the NVRTX branch today to test the performance increase on some of my projects. Unfortunately, I’m experiencing this crash as well (although mine simply says Fatal Error).
I was also able to reproduce this on a fresh project with an imported Metahuman.

What’s the process for providing the logs you need to investigate? I’d be happy to provide them, as this branch sounds very promising.

Thank you!

Hello @aseer002 and @seantgreen, welcome to the NVIDIA developer forums!

Regarding logs you should simply make sure that all NVIDIA related debug outputs are enabled in the output.log filter. Then simply attach the latest version of it when the crash occurs to this thread.

But does Metahuman even work correctly in UE 5.1 yet? I thought the plugin was still not updated.

@MarkusHoHo Thanks for sharing this. I’ll give this a go tomorrow and send over my logs.

As for the Metahumans, they seem to be working just fine outside of the grooms. At least for the few hours I messed around in that branch. I tested with a few old projects without any problems.

I should also add that the main Metahuman I use is a custom one that used the Mesh to Metahuman feature. I think the plugin is only required for creating new Metahumans using that tool.

Sorry this took so long! I’ve attached the log after adding a Metahuman with a groom to the level and it crashing. Please let me know if you need me to provide another or any more info.

Thank you!

MyProject.log (241.0 KB)

Just circling back on this. Has there been any news, or is there anything else I can provide?

Thank you.

Thanks for the Ping!

Right now we don’t need more information, I passed things on and am waiting as well for feedback.

Awesome, I’ll keep checking back then. Thanks so much Markus!

Hello, any solution on how to solve the above problem Goorm with unreal?