angle
(angle point_list1 point_list2)
The angle function returns the angle between the axis specified by two points. The function ignores Z coordinates different to zero of point_list1 and point_list2.
The angle is measured counterclockwise from the x-axis of the current custom coordinate system (CCS).
The function returns the value of the angle in radians.
: (angle '(10.0 5.0) '(20.0 7.0))
0.1974
: (angle '(2.0 3.33) '(4.6 5.7))
0.7392