Did the dress come with a UV_Map?
Then you can paint a black and white dosplacement map using the lay-out that came with the dress.
If the dress did not come with a UV-Layout you can make one using uvmapper free.
Black is no displacement and true white is full displacement.

 

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!