This is really amazing stuff. In the past (4.7 version) I used ProceduralMesh and SetProceduralMeshTriangles function. In new version 4.8.2 it doesn’t work. I don’t worry much because I like new API and I am going to use it instead.
I started from simple blueprint. It’s even easier to use than previous solution. I hope performance will be also better. THX
Here is my first mesh - rectangle from 3 squares, 8 verticies. I use 3 types of materials (brick, color, bush).
My first generation. Truncated octahedron (24 verticies, 44 faces). I use planar XY coordinates. Now I am going to calculate spherical UVs 
Spherical UV:
