1. Line Perpendicular to a Plane • A line perpendicular to a plane will appear perpendicular to the edge view of the plane. • A line perpendicular to a plane will appear true length in the edge view of the plane. • A line perpendicular to a plane is perpendicular to all lines in the plane. • Two perpendicular lines will appear perpendicular in a view that shows the TL of at least one of the lines.

2. Steps: • Find the Edge View of the plane. • Construct a line from Point O, perpendicular to the EV. • Project Point O back to the original views. • Show correct visibility of the line in all views.

3. Slope and Slope Direction of a Plane • Slope of a plane is the angle between the edge view of the plane and the horizontal reference plane (H). • Procedure: Find the edge view off the top view. (Find the point view of a line that is TL in the top view). Slope direction - direction of line/s of steepest slope - perpendicular to the direction of horizontal lines

4. Piercing Point by Edge View of the Plane • Intersection between a line a plane • Can be seen in the Edge View of the plane • intersection of edge view and the line • Visibility: • Plane can hide part of the line. Visibility of line changes at piercing point. • Compare relative distance/position of line and plane from the reference plane -- whichever is closer to the reference plane will be visible in the “previous” view.