Terrain Layers- Colormaps, and Textures.

I made a heightmap and colormap outside of unity. I can import the heightmap just fine. Is there a way to import a corresponding colormap on top of a height map, and then paint grey scale textures underneath it?

Not positive this is what you are asking for, but ATS has a colormap / shader package for free that you might want to look at or read on to see if the demo describes ‘how’

(the asset is free)