So has this been done now? I see these posts are from years ago and I still can’t find channels for decals and really want them.
One good example for a need is this (since you say you don’t have a clear need): I have a Hull shape which is a very large mesh. It’s curved at the nose obviously so If I want to use (large) decals on it the bounding box has to overlap the entire width of the hull shape. Now all meshes of the interior that are inside this hull shape will automatically also receive the decal and I really don’t want that. I want to place other decals on those interior walls so I can’t just turn of the decals on those.
So this is a case where I really need channels for decals!