[ODE] Trimesh problems

[Anders Olofsson]

The orginal dem/heightmap had 4470*2559 points, it would translate to 
almost 23 millions triangles. Maybe it could be done with a heightmap now, 
I dont know.

But there are other reasons too, I wanted to have a detailed coastline, the 
heightgrid resolution is 30 arc seconds, about 500-900 meters, not so 
detailed. And I also project the heightmap data (longitude/latitude -> 
orthographic), so the heightmap is not spaced regulary.

The heightmap is pretty flat at places so after I have optimized it, 
projected it and clipped out only the landmass (getting a coastline) its 
only about 0.6 millions of triangles.

Basically I'm converting this dem:
http://www.biologigrand.ac/lgh255/dem.jpg

to this mesh:
http://www.biologigrand.ac/lgh255/shot.jpg

Maybe you can spot where on earth it is?!, I actually live somewhere on the 
green thing. :)

But since it was orginally a heightmap some properties of the map applies 
to the mesh. No overhangs (folded geometry) for example.. So I can find out 
wich triangle is right below a point and then check for collision with that 
point and the plane that the triangle lies on. Maybe that would work.. 
Think I'll try.

--Anders Olofsson


At 00:25 2006-01-11, you wrote:
>If you really do have a heightmap, you're throwing away a good solution to 
>try to convert it to a trimesh.  Why do you say the heightmap would have 
>been too costly?
>Heightmaps have several advantages.  They get the collision right even 
>with full penetration, the normal calculations are always good, and they 
>are more efficient.
>
>Geoff