I must be missing something about how base material nodes work. I've created a base material node and hit 'View in 3D'. I have a heightmap, but it doesn't seem to show up in the 3D view, nor does the output for the base material have the heightmap I've plugged into the input. The roughness slider of the base material also…
It works fine if I set up the outputs and view them in 3D. And when I restarted designer, I was suddenly able to correctly view base materials in 3D as well, so I have no idea what was causing the problem. At least it's fixed.