It would be great if we could use existing materials as a Decal. Ideally, being able to use emission materials and VRay materials. This is not currently possible with the current Decal implementation, but perhaps it’s not so hard to implement?
Until we can more easily assign different materials and different mapping to each sides of a solid object, using Decals as a work around is helpful. Having to explode everything for simple texture mapping just seems wrong.