I already suggested this, but I can't find the post. So I'll rewrite it because it's an idea I'd really like to see in powder toy.
There should be some kind of decoration layer.
A decoration layer is a layer where you place decoration.
Example of use:Imagine you've made an awesome engine. Tough you want to make it look like an engine, but thatj way it wouldn't work.
So you get your decoration layer on and paint your engine.
Decoration layer would have no physics and, as the name says, it would be 100% decoration.
There would be added a new option on menu, that would be Decoration layer on/off. When it was on, the decoration menu would show up. The decoration menu is pretty much a drawing board. You get your colour then you paint your creation.
I'm sure this wouldn't be (too) laggy and would make some cool stuff.

@_-_David_-_ (View Post)
No, it's like a cover.
Did you even read the post?
Or atleast the example?
By the way it would be OVER the stuff, so if you covered an engine with this layer you'd only see the smoke going out of it and an image of an engine.
Tough if you disabled the decoration engine you'd see it working.
Can you do that the way you said david?
PS:the decoration layer would be static. The stuff behind it could be not.

Thanks for support.
In case people think this isn't possible I relember someone in the other thread saying something that it was possible.