Is there a maximum of surfaces you can substract from a bigger surface? Im trying to build a wall with 5 windows en 2 doors. I draw a big surface ex 12x3m, and several windows 1x1m and 2 doors 2x1m. I select the big surface, subtract objects, selecting all the doors and windows and when i press Enter some windows are disappearing. When i try to substract the windows and doors 1 by 1 i get a Boolean Operation failed after the 4th or 5th object. Some idea of what is going wrong?