[ODE] Need performance tips

[Frederic Ferland]

Hi!

I have written a small test system for learning about ODE.  I have a flat 
terrain represented by a box geom (until I add support for ODE planes) and 
20 crates also represented by box geoms.  All the crates start life in the 
air and fall on the ground in a pile.

The movement and performance is fine while the boxes are falling, but when 
all the crates are on the ground or on another crate, performance suffers 
quite a bit.  I know that this is happening because a lot of contact joints 
are being generated when the boxes are on the ground, but I don't really 
know how to improve the system.

So my question is: what can I do about it?  I though about detecting that 
the crates have stopped moving (how can this be detected in the first 
place?) and stop generating contact joints for crates that are no longer 
moving.  However, I think this will make the boxes fall through the ground, 
which is not really what I want :).  If I disable the crate bodies so that 
they don't fall through the ground, they will no longer interact with 
whatever might happen in the world (say another box falling in the pile for 
some reason.)  So what are my options?  Surely there's something that can 
be done about this?  How do games that deal with large worlds handle such 
problems?

Thanks for any help you can give!

______________________________________________________________

Frederic Ferland <fref@bigfoot.com>