Is Terrain Optimized?

Hi

Is the Terrain in Unity specially optimized compared to an ordinary mesh of the same size and detail? Following on from that, if I flattened an area of the terrain and imported a mesh of a mountain to sit on that flattened area, would I be incurring any extra overhead.

I'm assuming that where there are perfectly flat areas of terrain, Unity uses the minimum amount of tris to cover it, rather than a fixed resolution of tris all over... is this correct?

Thanks

Steve

Unity uses heightmaps with LOD for the terrain, so areas that have less detail and/or are farther away from the camera use fewer polygons. If you turn on wireframe rendering in the editor and zoom in and out of a terrain, you can see exactly what's being rendered.