CompuServe Thread

#Backwards Bumps

5 messages in this thread
#193021From: Neil W. BlevinsSep 28, 1995 4:46 PM
Just something that's been bothering me for a while. If I mirror an object which has mapping coordinates and has a bump map applied, the mirrored object seems to have the bumps going in instead of out. Is the mirror command flipping the mapping normals or something? Have I just gone crazy? The problem is solved with reapplying the mapping. – Neil
#193769From: Kyle J. McKisicOct 3, 1995 12:41 PM
when you apply a bump map to an object, the value (intensity) of the map is inverted on the opposite sides of the polygons you apply it to. – you can see this real quick by applwing planar mapping coordinates to a sphere, and applying a bump mapped material – the area on the opposite side of your object will have the bump map inverted. I'm guessing that when you mirror an object, the normals are getting flipped, thus showing the inverted area of your bump mapping. -Kyle
#193825From: Neil W. BlevinsOct 3, 1995 5:09 PM
Thanks Kyle, I guess there's no easy way to fix it. It seems like an odd bug because most humanoids and robots etc, have objects like hands and feet that need to be mirrored, and I and I'm sure others use the command a lot. – Neil
#193911From: Robert C. RitgerOct 4, 1995 12:31 AM
Neil: Just flip the normals after you mirror your objects and you should be in business. – Bob Ritger
#194031From: Neil W. BlevinsOct 4, 1995 4:10 PM
Thanks, I'll do just that. – Neil