I’m pretty sure this doesn’t currently exist, but it would be terrific if we could author our own floating geometry for use with decal materials. Cryengine currently allows for this with their decal materials, and open world games like GTA5 use this technique quite a bit to allow special decal materials to be used on geo wrapping around corners of buildings along with thin, tiling strips of geo with tire marks or lines of tar patchwork on roads. This also becomes exponentially more powerful in adding visual variety if those decal materials can have their alphas multiplied by the custom geometry’s own vert alphas so the same decal can fade in and out based on the geometry as well as its core material.
Is there anything that would prevent this from a technical standpoint, or it just a matter of adding the user functionality to the engine? If it’s the latter, I’d like to suggest it be added at some point down the road as it would allow a lot of flexibility for world builders.