Alright, I tried a few different ways and it works out so far, but I don’t have fine control so I have other problems. The last recommendation was to set the Lamp to shadows only, but this is not available in Cycles, only in BI. Is there a way to do this with Nodes? If yes, could someone give an example of how I would do this?
Also, other problems I have, that are not part of the initial question, but related to lighting is color bleeding. I might have a pink floor and a white ceiling, and as soon as it’s rendered, the ceiling is pink also. Setting Diffuse, Shadow and Transmission for the object, on and off does not make a difference, so I have been playing with the lighting. No success yet with the settings. Here is another image. Note, that in this image, there is no ceiling. I have 3 planes set to emission from above the room and 1 Sun Lamp with a low intensity to cast the sharp shadow. Overall, I have really good illumination, but slight adjustments in lighting that are necessary when adding objects, can really make the intensity too high. I don’t want to fixt that with a post process. It has to work with the intitial render. If I add a ceiling to this scene and point the camera up, the ceiling object has to be set to Shadow off, to allow the planes above to light through. I have all kinds of light collision problems. So this is turning into a second question, but if someone has input on this, I would appreciate it.