In case it is to interest to anyone, I managed to get the beams without any gaps. As you can see in the picture ofcourse. You can get the caustics with a black and white bitmap used as light gel. The white is the part that lets through the light. And when you put a terrain immediatly behind your scene then you can get the beams without having the gap. You can also see all these things in the 'caustics' picture that Guitta mentioned before. Ofcourse I had overlooked the terrain, and the fact that the caustics bitmap was black and white. :) Rynn.