Yes one layer for the UV map. But, if I wanted to make panel lines, that's one layer, if I wanted to add some service panels, markings, etc, then that's more layers. I have done many of my Textures in Corel Paintshop Pro for well over 20 years now, but I'm getting the idea I can do it all in 3D coat. Not 100% sure, but that's what I am getting out of it so far. I have used Gimp back when it was first released, but I am comfortable with Paintshop Pro.