Cool:)

and Thanks Mike!

You know, I was thinking, and maybe Mike can chime in on this one, but have you thought about using blend-shapes?

It would be time consuming, but if you are going for realism, this might give you...

Ok, nice animation by the way:)

So, correct me if I am wrong, but your 2 current questions are realy regarding possibly DEcreasing the physical radius of the "surface" particles, and then getting...

Maybe you could render out a playblast of what you are talking about?

so to see anything that we might be able to help you out with a bit more:)

You could also set your particles to die as they hit/exit the volume shape.