I am trying to populate the roads in my project with ism road markings that are essentially decals combined to make road markings. Path tracer can render the individual decal when placed on the mesh by hand but when combined into an ism path tracer can no longer see the material. I booted up the matrix sample to see how they had done it and it seems to have the same issue. Have tried r.ray tracing.geometry.instancedstaticmesh.culling 0 and r.raytracing.culling 0 and there is no change so I think it has something to do with the material. The error occurs when creating a static mesh from a decal. If anyone has encountered this and has a fix or workaround let me know.