When you get 3D proc, I hope there will be a way to make it stick to the geo? Not sure how that would work though because Procedurals are calc’d on the fly… hmm.
If you imagine 3 high contrast noise maps, flat mapped in 3 axes, the resulting output when the maps combine in 3D space will be either, white , black, dark grey, or light grey. This noise can be stuck to the geo, it’s crude but it works. I imagine it’s not that efficient either.
But I use the same idea to map dust onto a car tyre without it getting into the tyre grooves, there are so many uses for combined mapping coords.