BrightKidz Library
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The One Point Everything Shrinks Towards

About 11 minutes

Draw a road. Most people draw two lines going up the page, and it looks like a ladder lying down.

The road in front of a real house does not look like that. It gets narrower as it goes away, and so does everything beside it: the pavement, the row of parked cars, the fence, the line of the rooftops. All of it shrinking, all at once.

The surprising part is that they are not shrinking in random directions. Every single one of them is heading for the same dot, and once you know where that dot is, the whole drawing falls into place.

Why things shrink at all

Hold your thumb up at arm's length and it can cover a whole car parked down the street.

Your thumb has not grown. The car has not shrunk. What has changed is how wide a slice of your view each of them takes up, and something far away takes up a narrow slice.

Halve the distance and a thing looks twice as big. Double the distance and it looks half the size. Keep going and it heads towards a slice so narrow it is nothing at all — a point.

That point is where every receding line is going. It is called the vanishing point, and it is where things would finally shrink to zero if they went far enough.

Two rules, and that is the lot

Every line runs to the same single point A long horizontal line rules across the picture for the horizon, and one filled dot sits on it. Two straight edges climb from the bottom of the picture and meet exactly at that dot, making a road that narrows as it goes away. Five rungs cross the road, and each is shorter than the one below it and sits closer to it. Two upright posts stand on the grass to the left of the road, one near and one further off. The two posts are the same height in real life, and here the far one comes out about half as tall. Two faint dashed lines run through the feet of the posts and through their tops, and both of those dashed lines finish at the very same dot on the horizon. That is the rule which makes the shrinking come out right.
One dot on the horizon, and every edge running away from you aiming at it. The two posts are the same height in real life. The dashed lines through their feet and their tops both finish at the same dot, which is what decides how tall to draw the far one.

Rule one. Lines that run away from you all meet at the vanishing point. The two sides of the road, the top and bottom of a fence, the line where a wall meets the floor. Parallel in real life; converging on the page.

Rule two. Lines that run across your view stay level, and lines that stand up stay upright. The rungs of a ladder lying on the road, the top of a doorway, a lamp post. None of these are going away from you, so none of them aim anywhere.

Every line in a drawing is one of those two sorts. Decide which before you draw it and the picture builds itself.

You are drawing a straight street, looking down the middle of it. Which of these lines run to the vanishing point, and which stay flat or upright?

  • The kerb along the left side of the road
  • The line where a side wall meets the pavement
  • The gutter along the edge of a roof beside you
  • A lamp post standing on the pavement
  • The front door of a house facing straight at you
  • A zebra crossing's stripes going across the road

Where to put the dot

The vanishing point sits on the horizon, and the horizon is not "where the ground stops". It is a line at exactly the height of your own eyes.

That is why it moves. Lie on your stomach and the horizon drops to the ground, so you are looking along the road and everything towers over you. Stand on a wall and it lifts, and you find yourself looking down into things.

There is a quick check that works on any picture. Find something in it you know the height of — a person, a door — and see where the horizon line crosses it. If it crosses at a person's chest, the artist was crouching. If it crosses above every head, they were up a ladder.

  1. Rule a light horizontal line across your page, about a third of the way down. That is the horizon.
  2. Put a dot on it, anywhere. That is your vanishing point. Off-centre is more interesting than centre.
  3. From the bottom two corners of the page, rule a line to the dot. There is your road.
  4. Draw a lamp post beside the road, standing straight up. Any height you like.
  5. Now rule two faint lines from the dot: one through the foot of that post, one through its top.
  6. Every other lamp post goes between those two faint lines. Slide along, draw a post from the lower line up to the upper one, and it will be exactly the right height without you guessing once.

Step six is the whole trick. You are not judging how tall to make things. The two lines to the dot decide it for you, and they cannot be argued with.

You have drawn a road running to a vanishing point, with a row of fence posts beside it. The fourth post looks far too tall. What went wrong?

Go and check it on something real

Stand at one end of a corridor, or a long straight street, and hold a ruler up so it lies along the line where the wall meets the floor. Note the direction it points. Now do the same for where the wall meets the ceiling.

Follow both directions until they cross. That crossing is the vanishing point, it sits at the height of your eyes, and it is out there in every view you have ever had without once being visible.