Ok. Thanks for your replies. Nice tip with that terrain canvas. Thanks roch222. I find out my mistakes. I'm sure you know that the lake can be made using a water plane, cause that the way I make my lake. I was making two mistakes: 1. After grouping my positive terrains and my negative terrain, I never obtained a hole in the positive terrains. 2. I had an ocean instead a lake because I didn't set the ground plane on top of the water plane. I'll do a try to see how can I make a lake using a cilinder or a cube. I marked on my picture with the lake some black spots that I don't like. Why are they there? Did I make a mistake???