Standard windows have the advantage that they can be entered directly, and since they are predefined 3D objects, no further details need be specified. On the other hand, their dimensions can only be altered realistically within certain limits. If the size of a window selected from the 3D objects is changed, then the object itself, including all sub-objects, is scaled to reflect the new dimensions. For instance, if a window measures 1 x 1 m and its frame is 10 cm wide, then if its dimensions are changed to 2 x 2m the frame is ‘widened’ to 20 cm.
Window constructions avoid this problem, since all component parts are defined individually and the 3D object for the ‘finished’ window is automatically reconstructed when any details of the component parts are changed. The ‘Window construction’ dialog caters for all necessary modifications to windows.