PRIN. OF DRAFTING AND SHOP DRAWINGS - OD1641 - LESSON 1/TASK 1
PLANE PROJECTION PROBLEM
The lines drawn in step 3 define the right side view of plane 1-2-3-4.
In line theory we found that the end view of a line was a double-point. A similar
situation appears in the plane theory, which is explained by the following axiom:
The end view of a plane is a line (really several lines directly behind each
This may be verified by holding a sheet of paper horizontal to the ground and
rotating it until you are looking directly at one edge. Although it is a plane,
the sheet appears as a line.
So far, we have considered only straight lines.
Point, line, and
plane projection theory may be extended to include curved lines if we consider the
To a draftsman, a curved line is a visible line connecting three or more points
which form a smooth, nonlinear line.