This is called a mitre line. Project the top view of point 1 into the right side

view zone.

This is done by drawing a horizontal construction line to the right,

parallel to the principal plane line until it touches the 45, mitre line. When the

projection line touches the mitre line, it turns the corner, i.e., it goes from

horizontal to vertical.

To continue the projection line, draw a vertical

construction line, parallel to the vertical principal plane line, extending down

into the right side view zone. As before, don't be stingy with the lead; draw the

projection line through and beyond the horizontal projection line.

The

intersection of the two projection lines is the right side view of point 1. Label

it.

Several additional points should be made before leaving this problem. The location

of the front view of point 1 in relation to the top view is not random.

The

vertical line between the front and top views is parallel to the vertical principal

plane line. Figure 8 shows three views of point 1 and the projection lines used to

go from view to view.

The point views and lines form a perfect rectangle (four

sided figure with four right angles).

This *projection rectangle *enables the

draftsman to find any third view of a point when he is given the two other views.

This means that if we consider only three principle views (top, front, and right

side), there are only three possible projection problems.

FIGURE 8.

PROJECTION RECTANGLE.

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