Question that always comes to my mind when I read Dave Rosens post about their decal implementation (and I do so very often) is how the whole thing is supposed to work with skinned meshes - as far as I understand it, it's simply a scene node attached to another scene node, with geometry built from cropping intersecting faces. So these faces have to be skinned, too, don't they? Also, as you write you take ALL meshes in the scene into accout when creating the decal mesh, what if you move the scene node that the decal is attached to? Wouldn't that create some rather ugly artifacts when the decal moves with its parent node?