Here's what I've done in the past. Basically used abc texture blending to get the effect. If you don't know, using textures A and B will blend based on altitude. Using A B and C will blend A and B based on the alpha from C. So texture slot A is the body texture, slot B is blue (procedural or picture), and slot C is gray copied into the alpha channel (the level of gray 0 - 255, determines the transparency level) Does that make any sense? I just thought of a way without using the ABC method, I'll check it out and see if it works.