I just played a little around with collision avoiding without using trace.
They are still using ignore_models because those are quiete much in such a small room...
Here is the result:
Click
And here without ignore_models and just 10 spiders and an even smaller room:
Click

links don't work (for me)

I already fixed them

I like the one with ignore_models. In the one without ignore_models the spiders just stop when they hit each other.

Yes, thats because they get stuck in each other
I think with a little improvement it will work fine..

Nice work! I feel a little freaked out now, seeing all those spiders...eeee

Without tracing? but how ? ^^

Good work, great obstacle avoidance here, really got a buzz out of watching the spiders and loved the mass spilling out from null center, freaky

Yeah, that was pretty neat and creepy feeling.