hi I'm going to render large (or let me say very large) terrains using Direct3D 9 & C# (Visaul Studio 2008), what are my options? is there any good sample/tutorial/source code available? how can I read height maps of up to hundreds of MB? can I render them using only one Vertex buffer? should I use index buffer at all? what about textures, some days ago I read a topic about rendering 30 million triangles in gamedev, how can I do so? thanks for your helps

Possibly look into QuadTrees and Octtrees as well, both are rendering techniques to reduce the amount of useless renders in a given space.