I’ve got a scene in UE5.2 with some Megascan assets and a simple landscape. Everything looks fine in lit mode. However, when I switch to Path Tracing all meshes turn grey. I see the same behaviour in the mesh viewer as well. Everything is fine in lit mode, but everything turns into greyscale in path tracing mode.
I resolved this particular issue by disabling Substrate. Substrate doesn’t currently support path tracing. If you have substrate enabled, try disabling it.
UE5.2 did not support path traced substrate materials, but as of unreal 5.3 they are now supported (experimentally). If you upgrade a project to 5.3 these materials should work, if upgrading the project isn’t an option then you’ll need to disable substrate to use the path tracer for earlier versions.
