Selected Bibliography Architectural Graphics | Page 125

INCLINED LINES A more precise method for det ermining the vanishing point for an inclined set of parallel lines ye is as follows: --;1t------'~---ll-------7"'-----""------_.;.;..-,t'::::;......____..- • In the plan view of the perspective setup, we 1 · determine the vanishing point (VP) for a horizontal line in the same vertical plane as one / - / / - -/ -------~ __ of the inclined lines. : ----. W VP as the center, we swingan arc from the ith ! station point (SP to the pictu re plane (PP). ) : Mark this point A. i · In the perspective view, we mark point Aalong the horizon line (HL). / • A vanishing trace (VT) is aline along which all sets of parallel lines withina plane will appear to converge in linear perspective. The horizon line, for example, is the vanishing trace along which all horizontal set s of parallel lines converge. -. We establish a vertical vanishing trace (VT) through VP. This is the vanishing trace for the vertical plane containing the inclined set of parallel lines. - - --. From point A, we draw a line at the true slope (a) of the inclined set. • The point at which this line intersects VT is the vanishing point (VPi) for the inclined set of parallel lines. f'~AN / • The st eeper theinclined set of parallel lines, the farther up or down on its vanishing trace (VT) will be its vanishing point (VPi). • Note that if an inclined set of parallel lines rises upward and another set inthe same vertical plane falls at the sam but opposite angle to the e horizontal, the distances of their respective vanishing points (VPi1and Vfi2) above and below the horizon line (HL) are equal. PERSPECTIVE DRAWINGS/ 119