Selected Bibliography Architectural Graphics | Page 99

PICTORIAL EFFECTS OF PERSPECTIVE lines Parallel to the Picture Plane If parallel with the picture plane (PP), a se of t parallel lines will retain its orientation and not '•. t: ·-.., converge to avanishing point. Each line in the •. , set, however, will diminish in size according to 111 r.r: ·-. . . t'i~ret~t' 1 ~~~ .... ..... its distance from the observer. ·· .. ..~c~:: ...... -·· ..( ··· .. -·-···· a~ ' • In asimilar manner, shapes parallel with PP will .----~-++++--_-.._.~.~>-\_;;_----~7h!H'--1r---, _-:-: _ retain their form but diminish in size according ~\ <:.::: ···· to their distancefrom the observer. .....-·· ,· / . ~~ ~ .A/! lines Perpendicular to the Picture Plane ...... If perpendicular to the picture plane (PP), a set of parallel lines will appear to converge onthe horizon line (HL) at the center of vision (C) . ..... .;· lines Oblique to the Picture Plane • If oblique t othe picture plane (PP), aset of parallel lines will appe to converge toward ar a common vanishing point as it recedes. ..,_ ~------- If ahorizontal set of parallel lines is oblique to ~~--:---·_:-=--... - ------1---+-'-t--r.--::::-:::: ·:~:_"': ":~~ H_L_ · _ .. . . · ...... ···::7.· _:_ . PP, its vanishing point will always lie somewhere ·rt· ....... .... on the horizon line (HL) . If a set of parallel lines rises upward as it recedes. its vanishing point lies above HL.If it slopes downward as it recedes, its vanishing point lies below HL. ·. \ ~. ·. ··•.. \ ., '·:, . PERSPECTIVE DRAWINGS/ 93