Help different skinned clothes intercollision

[guoli]

Self-collision means... well, self-collision: a cloth colliding with itself.

To have two pieces of cloth colliding between each other (inter-collision), you need to make sure they have different phases. See:
http://obi.virtualmethodstudio.com/tutor...sions.html

Thanks, I changed their phases and it seemed work. 

But still, they penetrate sometimes. Is penetration not avoidable?