How do you....

Can't figure this one out. I have an animation of smoke traveling
through a tube. I need to put an disc in the middle of the tube
and have the smoke go around it. I'm created a matte to funnel
the smoke through the tube and I've tried to create another matte
on top of the other matte for the disc, but it won't let me.

Any ideas?


Thanks,

Doug Cwiak

Add a Repel behavior to the disc.