### Construction of the cylinder

Construction of an upright cylinder

Fig. 1 (cyl_09) We start off in exactly the same way as with the cone. Draw a square, its diagonals and its bisectors.

Fig. 2 Raise a vertical on the symmetry axis of the figure [?], in other words on the point of the circle at a tangent to the front side of the base square. Put in a point to mark the height of the square which is to frame the circle forming the top of the cylinder.

Fig. 3 Start from this point to build the cube which will encompass the cylinder.

Fig. 4 Don’t forget to draw the verticals, here marked in green.

Fig. 5 Place the second ellipse which will be tangential in 4 points and will bisect the diagonals at about two thirds of their length.

Fig. 6 Bring up the first vertical that will complete the right side of the cylinder.

Fig.7 cyl_15 Proceed likewise for the other side.

cyl_17 Look at these two cylinders. One is transparent [?], the other is shaded. On the transparent cylinder, the perspective seems to be wrong whereas the shaded cylinder doesn’t give this impression. And yet is strictly traced on the same construction. One has to admit that one doesn’t often get the chance to see a cylinder deformed like this. You will already have noticed that this optical phenomenon is created by the insufficient space between the vanishing points.

cyl_18 Here you see that if the vanishing points were to move further apart, drawing towards [?] the apices of this cluster of lines [?], the square would stretch out and the ellipse would be flattened out. Without changing the height in space, the circle of the cylinder base would no longer seem to tip over. [?]

cyl_00 This is what happened in this illustration. The general view shows that the space between the two vanishing points has widened and from the enlargement you can see that everything is better balanced and no longer offends our eye or our sense of logic.

Construction of a cylinder lying on its side cyl_16.jpg

A cylinder on its side is not so very different from a cylinder standing upright. Things get a bit more difficult when you draw several cylinders resting on each other [?] and placed on the same plane.

Fig. 1 (cylindre_02.jpg) This time you start off in angular perspective. The see-saw [?] we saw a moment ago could occur here since, for reasons of presentation, I have moved the two vanishing points closer together than I should really have done. These should be considered as symbolic diagrams and not as drawings designed to seduce the eye through their aesthetic qualities.

On the base square (vertical this time), draw the ellipse forming the left extremity of the cylinder.

Fig. 2 Draw all the vanishing lines required to construct a glass box encompassing the cylinder.

Fig. 3 Choose a depth by cutting the vanishing lines vertically. Do you see where the cylinder will contact this line?

Fig. 4 Draw the vanishing lines travelling towards the left vanishing point from the right corners of this glass cube.

Fig. 5 Finish the glass cube.

Fig. 6 Draw the diagonals of the furthest square.

Fig .7 Now place the ellipse in its appropriate position.

Fig. 8 Draw the two vanishing lines (in blue) showing the external contours of the cylinder. Notice, too, that the points situated on the diagonals are aligned and lead to the vanishing point.

Fig. 9 Put in as many as you like: they will come in handy for shading and give you an idea of the volume. They will also help you cut up those “slices of cake”.