Good evening. I''ve a bit of a problem... All I need to do is take the screen (X,Y) coordinates (-1 to 1) into world-position coordinates. My Z+ axis the the "vertical", and my camera is looking down at a variable angle, like in 3D RTS games (ie Earth 2140 + 2150, Z:Steel Soldiers, Ground Control). I am using Direct3D, in DirectX 7. The world itself is a heightmap grid, in a 2-dimensional array. I have a function already built to find the exact height of the terrain at any (X,Y) position. I want to find the world (X,Y) position that I am clicking at, basically. Any help will be highly appreciated... thanks!

What you are looking for is something called "Polygon Picking" I know Nehe''s site contains information on how to do this in OpenGL, but you should be able to find plenty of examples. For instance Direct X 8.0 has a sample app called PickPoly which does what your looking for.

If I had the DX8 SDK, that might help. Can''t download it... 56k modem. I will be getting cable, though... next month!

Whoohoo!!

Perhaps something else that will help is that I''m working in VB6, Enterprise Edition. I''m learning, and can read, C++ though, so don''t be shy with other languages.
So... again. Any chance of help?