VANISHING POINT DIAGRAM.
76. The somewhat symmetrical figure formed by the vanish ing traces of all the planes in the object, together with all vanishing points, HPP, and the vertical and horizontal tions of the station point, is called the Vanishing Point Diagram of the object.
77. Having found the complete vanishing point diagram of the house, the perspective projection may be drawn. VH, may be chosen in accordance with the kind of a perspective projection it is desired to produce (§ 29). In order that all the roof lines may be visible, VH, has been chosen far below VH. The result ing perspective is a somewhat exaggerated bird's-eye view.
The point eP will be found on VH„ vertically under the point e in the diagram. lies in the picture plane, and shows the true height of the vertical wall of the house. From e and eP, the horizontal edges of the walls of the main house vanish to vab and vad.
The points dr, V', mr, and or are found on the upper hori zontal edges of the main walls, vertically under the points where HPP is crossed by visual rays drawn through the points d, b, m, and o in the diagram. Vertical lines from dr and bP complete the visible vertical edges of the main house.
In a similar manner the perspective of the vertical walls of the porch is obtained.
Each roof line vanishes to its respective vanishing point. aVP vanishes at v". frc/P vanishes at These two lines inter sect in the point fP. The ridge of the main house passes through fP, vanishing at eb. gP eP vanishes at vge, passing through the point c", which has already been determined by the intersection of the two upper rear horizontal edges of the main walls. LP/JP vanishes at eg completing the perspective of the main roof.
In the porch, Pier vanishes at ek, passing through the point hi', already determined by the vertical walls of the porch. FP passes through IP, and vanishes at vu. From le the ridge of the porch roof vanishes at ed. From ne, a line vanishing at e'n will intersect the ridge in the point a", and represent the intersec tion of the roof planes Q and N. The vanishing point for oPitP falls outside the limits of the plate. ormr may be connected with a line which, if the drawing is accurate, will converge towards both TN and TR, and, if produced, would meet them at their intersection. • 78. While constructing the vanishing point diagram of an object, the student should constantly keep in mind the general statements made in the note under § 69.
Plate IV. should now be solved.