8th. Find vdi. The line • cif forms the intersection of the planes P and M. To this same system belongs the fina which forms the intersection of the planes P and M, 9th. Find vgb.. The line gb forms the intersection of the planes N and 0. To this same system belongs the line which forms the intersection between the planes N, and 0.
10th. Draw the vanishing traces of the planes M, N, 0, P, R, S, LT, and V, checking the construction of the vanishing points already found.
11th. vgf will now be determined by the intersection of TP and TN (§ 74). The lines forming the intersection of the plane P with the planes N and N, will vanish at vgf.
In a similar manner vb° will be determined by the intersection of TM and TO. The lines forming the intersections of the plane O with the planes M and M, will vanish at v".
The complete vanishing point diagram has now been found ; and it remains only to establish VH, in accordance with the given data, and construct the perspective projection of the house. A bird's-eye view has been chosen for the perspective projection in order to show as many of the roof lines as possible.
Each visible line in the perspective projection should be con tinued by a dotted construction line, to meet its particular van ishing point.
This problem will require more care in draughting than any of the previous ones, and the angles of the lines in revolved plan and elevation should be laid off with great precision. The stu
dent should not attempt to make the perspective projection until the vanishing point diagram is drawn with accuracy.
From the given data construct a perspective projection, using the plan of view for a diagram as indicated. HP P, SP", and SPli are given.
This plate need not be lettered, except as the student may find it an aid in construction.
Construct, by the method of perspective plan, a perspective projection of the object shown.in the given plan and elevations.
HPP and VH are to be taken coincident (§ 107), as in dicated on the plate.
The vanishing points (eb and vs") for the two systems of horizontal lines in the object are given. The line ab is to make en angle of 60° with the picture plane.
is the vertical trace of the horizontal plane on which the perspective plan is to be drawn. The corner (a") of this plan is given. . The perspective projection of the object is to rest on the horizontal plane determined by VH,.
An oblique projection of the object is given to assist in read ing the plan and elevations.
The student may use his discretion in lettering this plate. No letters are required except those indicating the positions of the station point and the measure points.