best terrain choice

Hi there.
A terrain could be made out of:
1. hmp
2. 3D surface
3. 3D model

1. The best approach would probably be (1). What are the advantages of using/rendering a hmp?
2. Does 3DGS support 3D surfaces?
3. If I'd have a generally flat terrain with very few relief I think it would be a waste to use a hmp, due to homogenity of triangles; instead I'd make a model with large triangles for the flat areas and small ones for crumpled terrain. Would it pay off?
What are your opinions, what do you use?

With terrains you have the options of using chunks (?) that make the terrain look more detailed, if I am right.

1) If you own the professional edition, you can use the automatic LOD system for Terrains. And terrains are split into chunks, which in most cases allows to cull big parts of the terrain. Also one could theroretically render without indices as triangle strips, which is again a bit faster than the standard aproach with indices, although I think that hmps use indices...
So the one big advantage is that gamestudio is able to get rid of quite a few triangles, without any efforts from your side in comparison to models. The disadvantage is, that you can´t really do things like caves with just terrain.

2) What is that supposed to be? Your graphicscard is designed to render triangles...

3) It is a lot more work and you will have to create your own chunks and fix the lighting at the transitions yourself, but than, this could lead to similarly fast and better looking results than hmps.

I would use gamestudios terrain system...

Thanks for the replies. Forgot about the chunks thing which pays off in full
By "3D surface" I meant a thickless 3D mesh, like a crumpled sheet of paper.
BTW does the engine use mipmap for terrains?