do uvmap to cloth but always not to know what is front and back of cloth,

but when marking front and back so that can do texture map separately for front and back of cloth.

what is the way to mark front and back when do uv map?

progress as follow:

1:creat obj

2:do uvmap

3:render uvmap

4:not to know that how to mark front and back of cloth 

in uv map

Thanks

The front, or "outside" of an object is pointed by the direction of the surface normals. So, normals pointing out describe faces that are facing outside.

Hope this helps.

Depending on your Modeling software, you could create groups and name the group Front or Back.  then UV Mapper will respect the names.

4 should be save mapped model, or add a step 5 save mapped model. The UV map (the template) is only a guide to how the UVs go, you must save the OBJ after making any changes to the UVs or the template will be useless. Of course this applies only if you made changes at step 2

thanks friends