@theluthier They’re actually just always greyed out for me if I have a subdivision. Even if they’re working. And you can change them while they’re greyed out. It’s bizarre. They also apparently removed the option to toggle between simple and catmull-clark with 2.92. But from what I’ve read multires in Blender has been a pretty big mess until recently. So this chaos doesn’t surprise me.
But the problem was just that view has to be 1 not 0, or the smoothing settings don’t get used.
