Hey,
It seems that Niagara mesh particles’ rotation is ignored by ray tracing. It produces all sorts of artifacts on the mesh itself (seems like where the rotated mesh goes behind the original orientated mesh) and the ray traced shadows won’t rotate at all. The 4.25 release notes mentions that Niagara mesh particles are in fact supported, so I wonder if this issue is affecting only me or this feature was added but never tested.
Regards,
Fisher