preserve uvmap while smoothing?

NAIMA

I am using turbosmooth and I know is destructive when used on uvmapped items , but I read somewhere that opensubd did preserve uvs , I tried and it doesn't may be I don't remember well ? or May be I am missing something ? Or may be there is another way to uvmap a low poly version of a mesh before smoothing? Or I just have to uvmap the high poly model and there is no other way ?

software 3dsmax 2017 .

LaurentiuN

Yes, open subd preserve the uvs of your model, if you use turbosmooth you can unwrapp your object after you added chamfers or support edges, and after that apply turbosmooth.

NAIMA

But I tried and opensubd doesn't preserve ... I have a stack from bottom to up like :

poly object edit poly
turbosmooth
shell
poly edit
uvmap
opensubd
and when I apply another uvmap to check its messed .

musashidan

Yes, this is a very old and ongoing issue that open subdiv was supposed to alleviate but it isn't 100%. There are many hacks and workarounds that people have tried over the years but none are 100% either. Try changing the open subdiv UV boundary dropdown to Smooth(edge&corner)

Eric Chadwick

Beware, you have modifiers in your stack which are topology-dependent. If you change the vertex count below them, the modifier will either be reset (uvw unwrap) or the topology will be messed up (edit poly).

It is best to work with as short a stack as possible. Learn which modifiers are resolution-dependent and be extra careful when using them.

Just a helpful word of warning from someone who has been there!