The approach to bump mapping is also non-traditional. From the start, everyone tries to make a surface appear more detailed. In other words, to show many details on a flat polygon, as if it was tesselated into billions of polygons - microdetails. Bump mapping helps achieve this goal, in part. But, for example, an elevation would never overlap what is behind it. Displacement mapping would be ideal for everyone, someday when it becomes a possibility. Right now it is unattainable, at least for real time applications. We took a totally different approach. We change normals, positions, we have overlapping. One could say we have real displacement mapping, except at the edges. There one can still notice that it is a flat surface.