[ODE] Status of TerrainAndCone

[Benoit Chaperot]

Contacts sorting means that the collide function can potentially generate more 
contact points than the user really wants to consider, and it is up to the user 
to request all contact points (say maximum 100), and then sort these contact 
points according to their significance (depth), and then only consider the most 
(say 5) significant contact points.
This is achieved using for example a qsort function.

It is something I did not include in the terrain class, because I think that 
should be done for all geom classes.

Your problem with sticky terrain, is it not the problem, solution, as explained 
in ODE User Guide ?

12.13. My rolling bodies (e.g. wheels) sometimes get stuck between geoms

Benoit

Ian Overgard wrote:

The main issue I've had is that objects tend to "stick" to the terrain, 
even when it's inappropriate. For instance, I can drive a vehicle 
straight up a cliff that's at an 80 or so degree angle to the ground and 
then park. Yes, you read that right, I can park a vehicle on a cliffside 
-- no sliding at all. Or drive straight up it if I want. I suppose it's 
a bit better than the previous version where objects tended to explode 
off of cliff faces, but it's still far from being very realistic. There 
are a couple workarounds -- if I increase the mass so that the pull of 
gravity generates enough force then objects tend to slide down the 
cliffface rather than being able to scale it. It still seems rather 
"sticky" though.

Of course, I might be doing something wrong myself. I noticed the 
documentation mentioned something about sorting contacts, although it 
wasn't specific enough that I was sure how I'd go about doing so; so at 
the moment I'm somewhat unsure if there's a solution that I've just been 
unable to implement.

As to how well it could work for an arcadey racing game, I suppose it 
would likely work alright as long as you keep the objects masses on the 
heavy side (mass of 1 unit isn't really sufficient, I had mine set to 
around 6-8 units in order to make it workable).

(I should of course make clear that this is just my own personal 
experiences with TerrainAndCone. There's always the possibility that 
I've just been using it wrong, although it seems like others have been 
having similiar problems).

--Ian