Finding the vanishing points for incline lines
b. To locate the inclined vanishing points, extend if necessary the
vertical lines A-B, C-D as shown in Figure 2-7 through the horizontal right
and left vanishing points.
Along these vertical lines will fall all the
vanishing points for the inclined lines and planes. Our problem now is to
find where the VPs fall on the vertical lines. As we view the object all of
the planes are inclined to the right; thus their vanishing points will fall
on the right vertical line C-D. From line SP-Y, construct angle "a" equal
to the inclined plane 1-2-3-4 in the elevation view.
Extend the line
defining this angle beyond line C-D. Construct a perpendicular to this line
intersection C-D at Y. Using a compass, lay off this perpendicular distance
on C-D from the VPR. This now is the VPR 1 for the inclined plane 1-2-3-4.
Proceed with this method on the remaining inclined planes.