In the stand-alone particle system for Softimage, there was a very useful noiseparameter.
I often used it like this:
Create a Cube Emitter, Emit particles with speed set to 0 and the volume parameter turned on (as opposed to surface or point), add some noise and you've got a swarm of insects. Really useful stuff.
Does this exist in XSI? (please say yes!)
Thanx,
Peter