Succinctly put Primorge.

When I used to make oil paintings, I based the compositions on collages I made from magazine cutouts.

Was the finished oil painting, or indeed the collage "sketch" piece, any less original than if I'd worked purely from pencil sketches? Nope, no less original. Just a different workflow.

That said, if I'd just painted a copy of a photo in magazine, verbatim, then there's probably a stronger argument that the composition of the finished oil painting was less than original. The execution would still have been original though... unless I'd copied another oil painting, stroke for stroke.

The way I see it a mesh is just a tool, like a paint brush, relative to composing a 2d image.

Of course, that's not to say there isn't a fine art to forging such a specialist tool... which can be a work of art in itself.

I guess a big part of the problem is this notion of originality. We are derivative creatures by our very nature, are we not? That's a good thing... it's why we survive... and indeed, so far, thrive, isn't it?