Hello Mr. Erim; The program automatically prevents the alignment of the two spaces. In other words, if you had a flat roof instead of a slope, when you get symmetry, the hollow part of the body would come together and disrupt the geometry. Therefore, whatever you do, the program automatically corrects when two beams get close enough to form a joint. We will try to find a solution to make this situation easier, but we cannot do this in this version. Therefore, you will have to interfere with their drawings.