PRIN. OF DRAFTING AND SHOP DRAWINGS - OD1641 - LESSON 1/TASK 1
FIGURE 13.
PLANE PROJECTION PROBLEM
SOLUTION.
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
other).
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.
h. Curves.
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
following axioms:
To a draftsman, a curved line is a visible line connecting three or more points
which form a smooth, nonlinear line.
13
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