Figure, door and crate

What to look at

Door top above the horizon, crate top below it, head on it: three heights read against one line.

The crate is the unit: everything else can be measured in crates.

The door is 1.2 heads tall; the crate is 0.57 heads. Ratios survive perspective, sizes do not.

What this scene is for

The three references most drawings actually need in one picture: a 1.75 m person, a 2.1 m door and a 1 m crate. Keep this one open while drawing anything whose size you are unsure of — it is the scale key for the rest of the library.

The mistake it settles

Treating the door as two metres of nothing in particular. A door is the most reliable measure in any scene because its height barely varies — 2.0 m in most of the world, 2.03 m in the United States — which is what makes it the default reference in the height-from-photo tool as well.

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 58% of the picture height — 437 px down on this 754 px render. Every other line in the scene is measured from it.
2. Two vanishing points on that line: 144 px beyond the left edge, and 1,415 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 1.75 m figure at 5.1 m: 456 px tall, with 91% of it below the horizon. That share is the camera height divided by the object's height (1.6 ÷ 1.75 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.