hi all. a little while ago when i made some guns for a half life mod i had a few conversations with some people who mentioned displacement mapping as an important technique to learn for games modelling. Then last week after seeing kurts use in his showreel I thought id come back to having a go. I did follow a youtube tutorial back when i was doing the guns but the couple that i was practicing on were quite complicated geometry wise i think to have the time to make mistakes on, so i left it alone.

I thought id have another go, just following a tutorial from a book that i have. In that tutorial the example uses a single poly plane to create some mountainous terrain with a 3D crater texture. I thought Id take the idea a little further, use a cube, and make my own texture in photoshop, just some random lines and squares and such. But in applying the displacement map, the geometry of the cube has broken at the seems. I have created a mental ray approximation node as the following example in the book...'Mastering Maya 2009' ...does this, but this hasn't solved the problem. If I can post the before and after shots below, would anyone be able to tell me how I can fix the problem. or is it just a case that for 3dimensional objects, i.e, not planes, u have to do the transfer maps technique.