How to put obstacles in the middle of foundation alignment?

1. First, carry out basic survey and pay-off, and measure the designed building pattern on the predetermined building ground according to the design size.

2. Secondly, in the process of pay-off, the ruler should be as horizontal as possible, and obstacles should be removed to keep the pay-off position horizontal.

2. Finally, use the alignment and vertical line to measure the corresponding sideline and complete the foundation lofting.