I’m pretty new to UE, and I’m working on creating a virtual Photography Studio for my football outfit designs, and I’ve encountered some issues that have me scratching my head. Here’s the rundown:
I designed a backdrop in Blender (images 1 and 2) and successfully imported it into Unreal Engine. The trouble starts when I add lighting and render the scene. Check out these artifacts in images 3 and 4.
What’s baffling is that there are no artifacts in the viewport (image 5)
I’ve even tried enabling Raytracing, but it looks horrible, even in the viewport (image 6)
What could be causing these artifacts during rendering? How can I get rid of these artifacts and achieve a clean render?
Any help or guidance you can provide would be appreciated! Thanks in advance!
To fix ray tracing, try the command raytracing.shadows.avoidselfintersectiontracedistance 1 or something similar. If you’re using nanite, that may solve your problem.
Your artifacts look like precision issues of some kind, but I’d need to examine them more to see if I’m correct. Are you using lumen/nanite/RT shadows?
Thanks for the response! Yes, I’m using Nanite for my backdrop, and the project initially employs Lumen for lighting. When using Lumen, I got these results: Image 3 and Image 4.
Enabling Raytracing introduced those strange ink-like shadows from the corresponding light sources.
Unfortunately, the command you suggested didn’t change anything. However, disallowing Nanite fixed everything!
I’m curious to know more about this. What could be causing Nanite to interact this way with my scene?
If what you’re experiencing is the phenomena I’m familiar with, then I think I know what’s to blame: essentially, when using nanite in UE5 and any sort of ray-tracing effects, the ray-tracing isn’t being calculated on the nanite mesh itself, as that would be wildly expensive. Instead, a proxy mesh is generated upon import of a nanite mesh, that’s much cheaper to trace rays against.
However, when that proxy mesh and nanite mesh don’t match eachother in big ways, ray-traced shadows will end up incorrectly shadowing the nanite mesh, leading to those weird blotches. In 5.3, this can also be largely avoided by using raytracing.nanite.mode 1, which causes the ray-traced and nanite meshes to match, if you have the memory for it.
