How can i active self collision in clothing tools?

Hi, I want to know How to active self-collision in clothing tools, is there someone can help me?
My character wears a double layer cloth, but when I simulate the cloth, it penetrates each other. That makes me crazy!
I try to adjust self-collision radius value to 1000000, it does not work at all!
And I tested Apex plugin in 3dsMax, It works perfectly in Max, And when I import the APEX file to UE4, my cloth also penetrate!!!
PLS Help Me!!!

263548-cloth-ue4.gif

I saw people with similar problems that solved by not scaling the model in Unreal, but only in 3DsMax/Maya. Is your model scaled on import?

are these two different layers of cloth?
afaik multiple cloth cant collide with each other

They should be able to if they belong to the same material section. That’s possible with APEX plugins on DCC apps. But doesn’t work in Unreal clothing tools.