Ray Tracing Geometry - Always Over Budget

Development Rendering
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1

I recently just started getting this warning - Ray Tracing Geometry - Always Over Budget. I started getting it after I went through my level and merged a whole bunch of actors. I thought this was going to help performance. I’ve seen a number of videos on how to handle this, but it wasn’t a problem before. I haven’t added anything or changed my lighting. Should I not have merged so many actors?

2

This one is tricky to answer. It is a lot about balancing things out. More actors need more draw calls, fewer actors means less culling. Depending on how the actors are merged it might be disadvantageous for the Lumen scene and you might need complex Distance Fields or Raytracing Proxies. I am not knowledgable about the inner works too much, just piecing together what I read here and there.

From personal experience I can tell you: I had a scene with 160 000 static mesh actors (none movable), spread across a hundred meters. I removed (not merged) about half of them and it had no noticable impact on performance (I was GPU bound). I also did a more synthetic test for the CPU and it was evident that Nanite scales much better than the traditional pipeline. So bottom line: you should not worry too much about actor count with Nanite and instead focus on other areas of performance improvements first.

3

Depends on how you merged them, if you combined them into packed level actors then it can be a good thing as long as you don’t get carried away.

If you’re merging the static meshes into one larger static mesh, that’s generally terrible. Only time you should be doing that is with HLODs.

4

Thanks. Both of those responses make sense. I have an earlier version that I can go back to. Shouldn’t take long to update to the current one. Also, I updated the project from 5.6 to 5.7.4. It didn’t to be a problem, but before try again, could any of this have been created from the update to 5.7.4?

5

Epic introduced Ray-Tracing Proxies (see Project Settings). I also got an Over Budget Warning when I went from 5.5 to 5.7. I enabled Ray-Tracing Proxies and the warning went away.

So yes, you probably got the warning because UE 5.7 changed something about the Ray-Tracing Geometry.