Problem with terrain + collision (meshes)

Blitz3D Forums/Blitz3D Programming/Problem with terrain + collision (meshes)

Pax(Posted 2006) [#1]
Hi, I have a terrain that does not want to work with collisions. I know my entitytypes are ok, because collisions work with other elements in my scene (also mesh based).

After some search, I think it is related to:
http://www.blitzbasic.com/Community/posts.php?topic=54531#608500

So my questions is big mesh terrains don't work correctly with blitz collision system because:
a) the large number of vertices?
b) the space between vertices, so the polygon area is actually very big to cover?
c) the scale compared to camera "size"?

I already chopped it into 3 chunks to lessen the amount of vertices per object, triplicated the amount of subdivisions and hiding it with entityalpha to have a collision object, set my scale bigger in my modeling app and froze it as to avoid scaling, and leaving it smaller, but still no joy and I'm running out of ideas.

Thanks for any idea of what's wrong + how to fix it.


Stevie G(Posted 2006) [#2]
I haven't experienced collision failures like this before. Which version of Blitz are you using? I remember that collisions were "tightened up" a while back. Not sure exactly what was different about them but it may help.

If the problem is as Madjack says then a simpler solution could be to move the pivots a very small amount away from the terrain mesh in the direction of the collision normals each frame.

Stevie


Pax(Posted 2006) [#3]
Stevie, thank you very much. My problem was "solved" after I saved my mesh as .b3d instead of .x (which is what my exporter directly outputs). Odd enough for me, but it is working now :)


Filax(Posted 2006) [#4]
Hi

For Terraed Pro i have the same problem... But i have try
to hunt this bug to know where is the problem.

IMO this bug is an entity number bug. When you have many patch
on the terrain, blitz collision become crazy and the camera
pass through the ground ...

I have try many stuff to remove this problem, but without
solution. Remember ! Blitz hait big entity number.


Pax(Posted 2006) [#5]
Hi Filax, after some more inspecting, I think my problem was not so much the format, but my workflow. I believe now that the thing with my terrain mesh as x, is that the vertices were unwelded (if so, must have happenned at the slicing time). Now, I didn't checked that one before because in blitz everything seemed ok (visually there were no problems). That's just a theory, because I'm using ultimateunwrap to save my geometry, so I don't really now if it's the import module of ultimateunwrap or that my .x model was corrupted to begin with. Just posted in case this helps.