[Normal to Surface] command generates a line that is normal to a surface from the surface point.
For the prompt "Specify a surface"
,
select a target surface
For the prompt "Specify the start point"
,
specify a point on the surface selected in the step 1.
For the prompt "Specify the end point"
,
specify the end point of the line. Since the point is limitted on the normal line
ou need to input the point in the other view.
Pressing B key specifies the line's end point for the point specified in Step 2 to be the middle of the line.
After the end point of the line is determined, the line is appended on the document.