NoteYou cannot paint
on a model in Mudbox unless it has UVs. For more information, see
Prepare a model for painting.
If UVs do not appear in the
UV View it
means either your model does not contain UV texture coordinates
or that no UVs exist for that particular subdivision level. If no
UVs exist, you’ll need to create and arrange them using a 3D modeling
application equipped with UV creation and editing tools. Maya and
3ds Max have tools for this purpose. If UVs only exist on the base
level of the model, you can recreate them for the current subdivision
level by selecting
Mesh > Recreate Level UVs.