Page 29 - 4234
P. 29
Figure 4.12
Thus if a line lies in a given plane, its traces lie on the respective traces of the plane, and
conversely.
If one projection of a line which lies in a plane is given or assumed, the other projection can
be found. Let the horizontal projection of line l, lying in the plane determined by lines m and n, be
given (Fig. 4.13). Line l 1 cuts m 1 and n 1 in points A 1 and B 1 respectively. The frontal projection of l
is determined by points A 2 and B 2.
Figure 4.13
Let the plane Δ is determined by parallel straight lines a and b. A frontal projection of point
А 2 is given, it is necessary to construct А 1 (Fig. 4.14).
Figure 4.14
29
