If I try to put a window into my wall it does not work. I have tried cutting out the space for the window an then directly modelling it there as well as building a window and then dragging it into the wall. Both ways the colour of the window frame and the glass seem to blend, or I cannot colour the part of the glass without colouring the whole wall with the same colour. It looks like the wall must be bend a little bit, which does not really make sense, since I have worked only with straight lines and angles of 90°.
Did anyone ever have a similar problem?