This function allows the user to measure the arc length on the section
line by the mouse. The user may click the left mouse button to select two nodes
on any section line. The selected nodes are marked with node number. When two
nodes are selected, the program displays the arc length, highlights it on the
screen, and outputs the relevant information in the message window. See Figure 5.1.9.
Figure 5.1.9 Measure Arc Length