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VR GPU Profiling - Instanced Foliage Performance Loss

Hello devs!

I’ve been working on a VR ArchViz project and have some performance losses using the foliage system. The performance hit is coming from a render thread named “Dynamic” under Frame\Scene\BasePass\View0 and View1, in the GPU Profiler. The hit is 3.35ms for each eye which is enough to drop my frames below my targets.

The scene is using static lighting and there is no vertex animation “world displacement” in my foliage materials. So my guess is “Dynamic” is referring to something else. Perhaps Culling?

Is there anyone out there who has experienced this before?

-Vince

Are you’re environment lights Static, Stationary or Moveable?

I think unless you explicitly tell your foliage to use Static Lighting, they’re dynamically lit. Static Lighting on Foliage / Instanced Meshes was also added in a more recent build too, I think either 4.7 or 4.8.

Hey guys,
We have a programmer working on making the two VR eye views used hardware instancing automatically. Currently it just naively duplicates the whole scene for each eye. That is most likely the problem you are seeing. It will probably be a few months before that change makes it to an official release, but just wanted to let you know that we are aware of this limitation and working on it.

All you can do now to help is keep your overall section count as low as humanly possible. Perhaps making your grass cluster meshes a bit larger will help? As long as the polycount per instance does not get crazy you should see gains from doing that.

Yup, everything is indeed static. I did forget to turn off “Dynamic Shadows” in each assets’ details, within the foliage tool. Although I was using purely static lighting, I made sure to turn off Dynamic shadows anyways, just in case. It seems like the issue is a duplication problem.

Thanks for the response!

-V

Thanks for the help and info, Ryan. I’ll keep digging into my performance issues and find and alternative solution for trees/grass. I have already had some better luck with more optimized assets/layouts. I’ll keep an eye on release notes on vegetation improvements in the next couple of versions. What’s the latest news on SLI with VR? Doubling performance is mighty appealing.

-V

That I do not know, sorry. I will see if somebody around here does and post back soon. Might be early next week.