Measuring with Your Pencil: Proportion and Perspective

Most lopsided sketches don't happen because someone can't draw — they happen because things were guessed instead of measured. Your pencil is more than a drawing tool: it's a measuring stick and a protractor that you always carry with you. In this lesson you'll learn to use it exactly that way — and as a result, draw buildings that stand up instead of toppling over.

The Pencil as a Measuring Instrument

Stretch your arm out fully, hold the pencil vertically and close one eye. Visually line up the pencil tip with the top edge of whatever you want to measure, for example the upper edge of a window. Your thumbnail slides down the pencil until it sits on the lower edge of the window. This distance between tip and thumb is now your unit of measurement — not in centimetres, but as a ratio.

Now comes the crucial step: you step this unit off across the subject. How many times does the window height fit into the width of the house? Twice, four times, six times? You count by repositioning the pencil again and again, without shifting your thumb and without bending your arm. That's exactly the point: the outstretched arm keeps the distance between eye and pencil constant. If you bend your elbow in between, the scale changes and all your numbers are worthless.

What you end up noting down aren't measurements but statements like: the door height fits three times into the façade height, and the ground floor is roughly twice as tall as the storey above it. You transfer such ratios onto your sheet, regardless of how large you're drawing. Pick one guiding measurement — usually the overall height or overall width of the main subject — draw it lightly onto the paper first, then divide it up according to the ratios you measured.

Taking Angles

Angles work in much the same way, except you hold the pencil at a slant. Stretch out your arm and tilt the pencil so that it visually lies exactly along the roof edge or windowsill you want to draw. Hold that angle, bring your arm down to the sketchbook without rotating your hand, and lay the pencil on the paper there. The angle you see is the angle you draw.

It helps to always think of the angle in relation to a fixed reference direction: how far does this roof edge deviate from the horizontal? Steep, or almost flat? When transferring it, compare against the top edge of your sheet, which serves as your horizontal. Two or three cleanly measured angles are often enough to set an entire façade correctly.

Eye Level as the First Line

Before you draw anything else, run a horizontal line across the sheet: your eye level. It lies exactly where your gaze goes horizontally into the subject. You find it by looking straight ahead — everything above it you see from below, everything beneath it from above. On a street you recognise it by the way windowsills and door lintels visually crowd together there and edges become almost horizontal.

This single line determines the mood: if you're sitting on a step, it sits low and the buildings seem tall. If you're standing, it lies roughly at lintel height. Draw it lightly, but draw it first.

One Vanishing Point, Two Vanishing Points

When you look down a street, all the edges leading away from you — eaves, rows of windows, kerb lines — converge on a single point on your eye-level line. One vanishing point is enough. If instead you're standing in front of the corner of a building and see two façades at once, you need two vanishing points, both on the same eye level, one to the left, one to the right.

These points almost always lie outside your sheet, often far outside. That's no problem and no reason to force them. Instead of drawing guidelines to an invented point, you sight the direction of each individual edge with your pencil and transfer it. The vanishing point remains a checking idea in your head: if all the eaves run slightly downwards and all the base lines slightly upwards towards eye level, things are right. Verticals stay vertical throughout — parallel to the side edge of the sheet.

Three Mistakes That Keep Coming Up

Roofs that are too steep happen because we know a roof is pointed, and we draw that idea more strongly than the shallow angle we actually see. Measured angles are almost always flatter than felt ones. The second mistake: drawing distant windows the same size as near ones. Measure the first window axis and the last visible one — the difference is greater than you think, and the gaps between the axes also shrink towards the back. The third mistake is tilting verticals. Check them by holding the pencil vertically in front of a building edge, and check on the sheet against the side edge.

Exercise

Find a street leading away from you and sit so that you can see at least three buildings one behind the other. Set a timer for 15 minutes. First draw the eye level as a horizontal line. Then, with an outstretched arm, take three angles: the eaves of the nearest façade, the kerb line, and one row of windows. Transfer them and add only the verticals of the building edges plus the rough window fields as rectangles. No tiles, no panes, no hatching. At the end, check whether all the verticals are parallel and all the receding lines converge on the eye level.

Key Points

Arm outstretched, one eye closed, thumb as a marker — without a constant distance there's no usable measurement. Eye level is the first line on the sheet and the answer to most perspective questions. Measured angles are flatter than felt ones, and vanishing points are perfectly free to disappear beyond the edge of the page.