Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . of vision, but at a point to the right or left of it,and at a distance from it, depending on the angle which thesides make with the Now, in parallel perspective wedeal with only one vanishing point—the centre of vision; butthere are really two: for all lines parallel to the , if pro-duced to an infinitely great distance, will appear to meet at apoint to right or left. Hence in parallel perspective only onevanishing point is of practical utility. However, when thecub
Perspective and geometrical drawing adapted to the use of candidates for second and third-class teachers' certificates . of vision, but at a point to the right or left of it,and at a distance from it, depending on the angle which thesides make with the Now, in parallel perspective wedeal with only one vanishing point—the centre of vision; butthere are really two: for all lines parallel to the , if pro-duced to an infinitely great distance, will appear to meet at apoint to right or left. Hence in parallel perspective only onevanishing point is of practical utility. However, when thecube is moved out of its parallel position, this apparently-hidden vanishing point appears, and strikes the horizon at adistance from the centre of vision, depending on its angle, asalready explained. Thus :— ^ In Fig. 59, AB on left side shows the base of a cube inparallel, perspective, while in Fig. 60 AB has been movedaround to position of AD, and AC will not now vanish , but to a point Y to right of it; so also AD will notvanish at a point parallel to AB, but at X, a point in the ANGULAR PERSPECTIVE. 97. Fr 60. horizontal line to left of We wi].. now proceed toascertain the positions of these points. Example 1.—Draw a square (side 4) lying on ground; sidesmake an angle of 45° with picture plane, and the angletouches the at a point 4 to the right; scale ^ =-\\ DRAWING.
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Keywords: ., bookcentury1800, booksubjectgeometricald, booksubjectperspective
