Thursday, March 26, 2015

Circles and Cylinders in Perspective

A circle drawn in perspective looks like an ellipse. An ellipse touches the center of each side of the square in which it fits. Drawing an ellipse mechanically is a little laborious, but it sure looks great in the end. First, find the center of the rectangle. Use this center to draw the following circles: draw a circle with a diameter of the width of the rectangle and a circle with a diameter of the length of the rectangle. Draw several lines from the center of the circles to each circle. Mark the points where these lines intersect the circles. For all the points on the small circle, draw lines parallel to the length line. For all points on the large circle, draw lines parallel to the width line. The points where these lines meet are points on the ellipse, which you can now draw. Norling offers two other ways to draw an ellipse, but I prefer this one. Last thing to note: the two axes of the ellipse meet at a right angle.

Drawing a cylinder in perspective was really frustrating. I spent hours futilely trying to draw a cylinder contained within a rectangular box with two square sides. Finally, I realized that the problem was that I was not actually drawing a  square-shaped side in perspective, which is why, as I elongated my box, the ellipses on the further ends were harder and harder to draw without warping. To draw a cylinder in perspective, imagine that it is contained in a box with two square sides. Draw this box in perspective. Find the center of each square side by drawing intersecting diagonals. Draw a line connecting these centers. Within each square side, draw a line that passes through each center at a perpendicular to the center-connecting line: this line is the long axis of the ellipse. Then, draw the ellipses, remembering that an ellipse must touch the center (in perspective) of each side of the square.

1 comment:

  1. Patrica...question
    I too have been going through Bargue. I was curious, are you just drawing "extra" schemata and plates for practice?
    Thanks
    Paul

    ReplyDelete