The Elements of Perspective

PROBLEM XIX.

Reading edition

PROBLEM XIX.

TO FIND THE VANISHING-POINT OF STEEPEST LINES IN AN INCLINED PLANE WHOSE SIGHT-LINE IS GIVEN.

Fig. 49.

Let V X, Fig. 49., be the given sight-line.

Produce it to cut the horizontal sight-line in X.

Therefore X is the vanishing-point of horizontal lines in the given inclined plane. (Problem XVIII.)

Join T X, and draw T Y at right angles to T X.

From Y erect the vertical Y P, cutting the sight-line of the inclined plane in P.

Then P is the vanishing-point of steepest lines in the plane.

All lines drawn to it, as Q P, R P, N P, etc., are the steepest possible in the plane; and all lines drawn to X, as Q X, O X, etc., are horizontal, and at right angles to the lines P Q, P R, etc.

Notes in this chapter

Note 1 · : That is to say, the vanishing-point of horizontal lines drawn at right angles to the lines whose vanishing-point is X.] Return to text Note 2 · Therefore Y is the rectangular vanishing-point corresponding to X.[Footnote 29]