Modo's mirroring = normal artifacts

JoshWilkinson

I'm getting this issue in two different parts of my mesh; the two parts that are mirrored.

When mirroring geometry, unless I'm mistaken I always have to flip the polygons in Modo (and all other modeling apps for that matter) but despite this, I'm getting errors when I render out a normal map. What is causing this? It looks fine in the view port but is unsuitable for rendering any sort of map. Is there something else I need to flip as well?

Bek

Can't say I've ever had that, but I don't bake in modo. When you mirror are you enabling merge vertices? If not, try that. If welding/mesh cleanup ruins the UV's for the mirrored piece, then you need to use the Vertex > Merge option (not the Merge Tool) with an fixed range.

Could you do this without mirroring the highpoly? If the two highpoly pieces are symmetrical couldn't you just duplicate? Or perhaps is there a way to bake from only the one highpoly piece? That would be more efficient when it comes to exporting.

Might also have something to do with the mirrored piece having a weird pivot/center?

Swizzle

Try going to the Lists tab and expand Other Maps, then delete any vertex normal maps. Sometimes when you mirror geo with vertex normals, it does really strange things that requires deleting or resetting vertex normals.

Alternatively, if you're the one who made the vertex normals and you want to keep the ones that are on the correct faces, select the offending faces, right click on your vertex normal map, and press Clear.

Farfarer

Yeah, the vertex normal maps are locked in object space - so when rotating/mirroring a mesh with a vertex normal map, the normals don't get updated.

So you can either remove the vertex normal map (you can find it in the "Other Maps" section of the vertex map list - just select it, right click and hit Delete), or upgrade to 801 which has some improvements when dealing with meshes with vertex normal maps.

JoshWilkinson

Thanks a lot guys. Ya the mirrored mesh had a normals map stored in it's list. Not sure if it was a vertex normal (all it said was "normal") but clearing the maps from the high poly fixed it regardless.

Thanks for the help