It's similar to a bump-map in that case that it's used to make a relief in a surface, but the difference is that unlike a bump-map the displacement-map actually displaces the surface. When you see a bump-map from the side you don't see any relief, with a displacement-map you'll see real bumps and ripples. This can give some strange results when you use it on skine and you have very tight clothing. Make sure that besides the node-settings in the material-room you also set the box in the rendersettings.

regards,

Bopperthijs

-How can you improve things when you don't make mistakes?