If anyone could tell me the best way to create such an illusion under Houdini, would be greatly appreciated.
And when I mean deflating, I am referring to the swirrling effect one normally does.
theshak

To inflate a balloon I take it you are starting with a flat piece of rubber then changing it's shape to take the form of a fully inflated balloon.

One way would be to model inbetween shapes then use a sequence blend to link all the different stages of the balloon inflation.

At some point when the balloon has some volume, you could use a metaball or a few fed in to a bulge SOP to push the balloon out to get the final inflated shape.

To deflate the balloon, you could use a cache SOP, cache the inflation of the balloon and then reverse it. Use some noise in a point SOP to animate some nice noisey waves through the balloon. Best to do this on the static balloon first.

I guess you also want to animate the balloon flying all over the place. As a first attempt, you could draw a curve for the path then use the align SOP to animate the balloon along the path after you do the deformations. You could also fly a particle around using some noise generated by a pop network. You could have it bounce off walls that way.

Many other ways to do this effect.

:wink: Thanks for the tips
theshak