Quote - Yeah !! found a solution, the two layer are facing in opposite direction, i have applied a linear displacement of 3mm and the dress seem thicker, 3mm is probably too much and need some adjustment

So, "shell" plus displacement - that sounds like a plan! I have some clothing that is already made like that, and has different materials for inside and outside, so it should be easy to try it for myself.

Quote - > Quote - I still wonder though if you can get the same effect by applying that displacement to a single.sided cloth :)

 

if you have only one layer you just move the mesh in one direction, maybe this work, the better is to try it

I don't think it will have any useful effect either - but don't listen to me, I haven't tried it either. ;)

Quote - > Quote -

Just want to point out that the "Shell" command in Silo will do that for you - Just remember, you may need to  to reverse normals afterwards depending on the direction you "Shell".

yes but your displacement is 'baked' on the mesh and you cannot adjust it anymore on render.

I don't know about Silo, but in Anim8or the shell tool does just what you described in your first post - duplicates the surface, and joins the two surfaces around the edges. It's much easier that way, and you have interactive control over the thickness of the result. Just drag the mouse further to increase the distance. I find it's a good idea to bevel the edges after "shelling" to smooth the result.