Enable WPO on foliage to get raytracing working on animated foliage

so im trying to use megascans trees in UE5, everything is fine and i can enable WPO if the object is a static mesh however when i want to use the trees with the foliage tool I cannot do this, and the shadows are messed up/static with raytracing enabled for instanced meshes. I have tried the workaround from this video: Troubleshooting FOLIAGE issues in Unreal Engine - YouTube (he talks about it in issue2) this sort of works but its a hassle as he says and has a bad performance impact. so i guess what im saying is I dont understand why there is no easy way to get this working? and thus, what is the industry standard way to get animated foliage working with raytracing shadows in UE5. like am i approaching the issue from a completely wrong angle?

I also tried this console command: r.Raytracing.Geometry.InstancedStaticMeshes.enableWPO 1 and It did absolutely nothing not sure if this works in UE5 and only 4 as i found it in this video, NvRTX Unreal Engine 4 Branch: Ray Traced Foliage - YouTube.

Unreal’s Ray Tracing quality is terrible, like inefficient GI, annoying reflection noise, low support for plant shadows. They prefer to use their own technologies in UE5, such as Lumen and Virtual Shadow Maps. RT is eliminated in UE5, so we can see EPIC is cautions about NVIDIA, this is a company that wants to control its own destiny.

What are you talking about?

No company out there has successfully managed to merge hardware ray tracing with rasterization efficiently. Rasterized effects like WPO are notoriously difficult to combine with ray tracing, which often relies on acceleration structures that are hard to update in realtime when actual geometry deforms. And ray tracing has notorious issues with performance when traversing many translucent, opacity mapped triangles, such as leaves on the trees.

It’s not that Epic has made some boneheaded decision. It’s that this is a problem no one in the industry managed to solve yet, so Epic did what they usually do. They went the conservative route, because they want their engine to be an actual production engine people can rely on to ship AAA games, instead of engine which has all the new shiny features but doesn’t perform and can’t be relied on in production.

HW ray traced GI in UE4 was quite slow, and yet it was one of the fastest realtime brute force GI solutions that ever existed. If that didn’t show we’re not there yet, despite what nVidia may claim, IDK what will. How can you blame them for recognizing that and coming up with Lumen instead?

I mean look at nVidia themselves, with their RTXGI. All they could come up with is pretty much the same thing as Lumen, a volumetric probe based solution. Except with much poorer probe distribution, which has to be done manually by the user on top of that, instead being automatic, like it is with Lumen.

1 Like