Mechanical Drawings and Construction Drawings

Each projection of the object that is constructed (for example, a pump or a house) can be handled as a subpicture on level 1. If any standard parts are added (for example, a nozzle or a window) to the object, then they probably should form level 2 subpictures. All new created information should then belong to a subpicture of its own on level 2. Subpictures on level 3 can be used freely during the creation of the drawing, when for example, duplicating information. By keeping the subpicture structure in good order, operations like "exchange all windows in the house" can be done easily by one command.