Cylinders at three heights

What to look at

The rim nearest eye level is the thinnest ellipse; bases far below it are the roundest.

The tall cylinder's top is above eye level, so you see its underside curve the other way.

Every ellipse's minor axis points at the cylinder's axis, not at the horizon.

What this scene is for

Three 0.6 m cylinders at 0.4, 1 and 2 m tall from a camera at 1.2 m: the reference for ellipse degree. Use it for cups, cans, tins, columns, tree trunks, wheels and every other round thing that has to sit in a drawing.

The mistake it settles

Drawing every ellipse the same. An ellipse opens as it gets further from eye level: the rim nearest the horizon is nearly a line, the base of the short cylinder is wide open, and the top of the tall one — above eye level — curves the other way entirely.

The camera

Measured off this render

Taken from the same camera model the tool draws with, on the 1340 × 754 PNG above.

Draw it from these numbers

1. Rule the horizon across the sheet at 40% of the picture height — 302 px down on this 754 px render. Every other line in the scene is measured from it.
2. Two vanishing points on that line: 196 px from the left edge, and 2,909 px beyond the right edge — far enough out that you should match the grid angles instead of chasing it.
3. Set the scale from the 2 m cylinder at 7.5 m: 359 px tall, with 60% of it below the horizon. That share is the camera height divided by the object's height (1.2 ÷ 2 m), and it is the same for every object of that height anywhere in the picture.

Open the reference in the tool to move the camera, change the lens, or add your own objects at real sizes; the share link keeps your version. Draw over the PNG at 30–50% opacity in any app with layers.