Here's good one. I don't know if you can even do this in particle illusion, but I would rather start here.
I'm working on a movie where the final sequence involves storm clouds swirling around in the sky to form a vortex. Is there any way to do this in particle illusion or am I going to have to shell out some big dollars for one of those over-rated programs?
I'm pretty certain it's doable, but it's all a bit subjective since so much of it depends on the look you want in the end. Blending the clouds in to become the vortex itself might require a lot of little tweaks and hand animation. It's really going to depend on how comfortable you are with tweaking emitters and animating in pI.
The smoke suction emitter from a month ago is a pretty good start to creating a vortex, it really just needs some tweaking of the colours (lose the tint, have the particles go from your cloud colour to black over the course of their life to seem like it's funneling off to somewhere). You could probably use Force objects to push some cloud emitters into the area where you want the vortex to form and then fade them out as you bring your vortex emitter in.