One side of the third line refers to the outer line of the outer wall, the center line of the outer wall, the clear long line of the inner wall and the construction area.

According to the data commonly used in engineering quantity calculation, the third line refers to the center line of the external wall, the outer line of the external wall and the net long line of the internal wall of the building, and the first side refers to the construction area of the building.

One side of the three lines can be used as the basis for continuous calculation of quantities. Make full use of its * * * and adjust its personality to improve the calculation speed.