Displacement map causes strange effects I am working on an old pool table set and I came across a problem when I tried to add a displacement map to my cue ball.

This is it without the displacement map.



But to add more realism (and to show it had been used a lot) I wanted to add small dents and scratches to the ball as well.

The problem is as soon as I added the displacement map this happened.



As you can see the glossiness is made very glossy in the bottom, the scratches are dotted and not indented, and the bumps do not like bumps.

Obviously I have made a mistake somewhere and I would really appreciate any help in fixing the problem.



You can download the files used from this dropbox folder
It looks like you are trying to use bump maps as normal maps.  If your texture data is black and white you should use it as a bump map.  Normal maps are made up of RGB data that maps to the XYZ components of normal vectors.  They generally look purplish blue.  

Plug the output of your noise texture and scratch texture into a mix node, and then plug the output of the mix node into the displacement slot of your material output.



And the result: