This Lisp is helpful while creating the base maps using Total station data. Generally the surveyors who capture the data take the three corners of a building as standard engineering practices. With these three points the plan of the building or the structure needs to be drafted. As we all know that it’s easy to join the points with lines, but it is time consuming to complete the shape of the building. This lisp automatically creates a closed polygon based on the three selected points. The first line will be drawn between fist two selected points and the 2nd line will be drawn considering the 3rd point distance and a line perpendicular to the first line. Further 3rd and 4th line remains parallel to the first and second line. With this approach lisp accommodates minor error that might have happened while capturing building corners.