Heres another use of the A+B+C and D blend. After creating the terrain I exported the Altitude mask of the terrain and used it as a stencil to show me where the lowest point of the terrain was. I then brought that in as texture D to drive diffusion. This creates the dark mud hole appearance around the water. For more in-depth tutorial visit: [BryceTech](http://www.brycetech.com/) Left sidebar under advanced click Material Lab specifically starting with Part 8. But this entire tutorial is a must see for all serious Brycers.