As in the A+B blend the A+B+C will also allow textures A and B attributes to show through where ever Texture Cs alpha dictates. Here textures A and B show their bump height information. The A+B+C blend is very powerful. You can get some pretty extraordinary results when mixing terrain textures. Remember that any texture can also be a 2D texture. This means that you can custom make texture Cs alpha. Furthermore, you can change the mapping mode of any texture.