Ceiling layout is an important part of construction drawing plane system. As the drafter of the construction drawing, the details of the installation of electromechanical points, HVAC equipment and lamps can only be handed over to other professions after the ceiling layout is established.

Ceiling modeling diagram and ceiling lamp positioning diagram depend on how the drawing catalogue is arranged and how the contents expressed in the drawings are reflected. The modeling line on the ceiling diagram, that is, the orthogonal projection line from the plane to the top, is the orthogonal projection line from the bottom up, not from the bottom up. Many designers are extremely confused about this.