From a, half of mP·, draw quadrant ab, from b (half base), draw line from b to half Dist., which intersects Sm at P, precisely the same point as would be obtained by using the whole distance.
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How to put a Given Triangle or other Rectilineal Figure into Perspective
Here we simply put three points into perspective to obtain the given triangle A, or five points to obtain the five-sided figure at B. So can we deal with any number of figures placed at any angle.
Fig. 114.
Both the above figures are placed in the same diagram, showing how any number can be drawn by means of the same point of sight and the same point of distance, which makes them belong to the same picture.
It is to be noted that the figures appear reversed in the perspective. That is, in the geometrical triangle the base at ab is uppermost, whereas in the perspective ab is lowermost, yet both are nearest to the ground line.