I have a very frustrating error with Polybrush - it's essentially unusable. I create a default plane. I install polyrbsuh (beta) from the asset store. I create a shader from the 'Height Blend' When I assign it it turns my mesh black when I assign and it says "It doesn't look like any of the materials on this object support texture blending!" Why? It's a polybrush shader! None of the shaders work, I've tested in multiple projects, on 2018, and 2019 version - what is going on??