Perspective Ruler Online
Place the vanishing points, then draw. Every stroke snaps to the point it aims at, like Clip Studio's ruler, in the browser.
That grid took you a minute. Forty-six are already drawn.
Every lens from 24 to 85 mm and every camera height, as true vector sheets for A4, A3, Letter and Tabloid — print one and start drawing. The same 46 grids come as transparent layers for Procreate, Photoshop, Clip Studio and Krita. 252 finished scenes to draw straight over, each one carrying the camera that made it. And thirty exercises that teach the whole thing, each with its construction worked on the next page. Every one has a free starter, so you can try the real files first.
Free starters: seven sheets, twenty scenes, five exercises. The three grid-and-reference packs together are $24, seven less than the parts. The printable templates and the reference library stay free whatever you do — a pack sold is what keeps them that way.
Draw straight toward the vanishing point without a ruler
A perspective ruler is the oldest perspective tool there is: a pin in the vanishing point and a straightedge that pivots on it. This page is that ruler in a browser. Put the vanishing points where the scene needs them, then draw: every stroke is projected onto the line through its start point and the vanishing point it aims at, so a rough stroke becomes a ruled line that converges correctly. Verticals stay vertical in a level view or snap to the third point in a tilted one. It is the same behaviour as the perspective ruler in Clip Studio Paint and the assistants in Krita, without opening either.
Placing the points
Drag the VP1 and VP2 dots; when a point is off the canvas, an arrow at the edge shows where it went, and you can still drag it. Level VP1 and VP2 puts them on one horizon. Set from a camera places both points for a given lens and rotation, which is the reliable way to get a normal-looking view: for a 35 mm lens turned 32°, they land about a picture-width outside each edge. Tick Third point for a camera looking up or down, then click on the canvas to place VP3 far above or below.
Drawing
Block in with snapped strokes: the near corner of a box first, then its edges to each point, then the verticals. Switch to freehand for anything organic. The snap bar can also force a stroke to a particular point, which helps when the two directions are close together near the horizon. Undo, redo and clear are in the top bar; Ctrl/Cmd+Z works too.
Over a photo
Drop a reference photo onto the canvas and set its opacity. Place the points on the photo's own converging edges, or read them with the vanishing point finder first and copy them over; then everything you draw converges the way the photo does. This is the fastest way to add a building, a piece of furniture or a sign into a photographed scene.
More tools
For a full grid rather than a ruler, the 2-point and 3-point grids; for the same snapping inside a painting app, Clip Studio's perspective ruler and Krita's assistants; for what to draw, how to draw perspective and how to draw a room in perspective.
Questions
What is a perspective ruler?
A ruler that pivots on a vanishing point, so every line you draw with it converges correctly. Physically it is a pin and a straightedge; in Clip Studio Paint it is the Perspective Ruler; here it is a canvas where each stroke is projected onto the line from its start point to the vanishing point it aims at.
How does the snapping decide which point to use?
From the direction of the first few pixels of the stroke. If you start drawing roughly toward VP1, the stroke locks to VP1; toward VP2, to VP2; up or down, to vertical (or VP3 when the third point is on). Start the stroke a little more clearly along the edge you mean if it picks the wrong one, or force a point in the snap bar.
How do I draw a freehand line?
Choose freehand in the snap bar. Curves, figures and lettering go on freehand; block-ins go on snapped strokes.
Where should the vanishing points be?
For a normal lens they belong outside the picture, roughly a picture-width out on each side for a 35–50 mm view. Place VP1 and VP2 from a lens and rotation puts them at the right spacing automatically; the vanishing point distance calculator gives the number.
Can I draw over a photo?
Yes. Drop, paste or open a photo; it sits under the sketch at the opacity you set. Drag the vanishing point dots onto the photo's converging edges, or run the photo through the vanishing point finder to get them exactly. The photo never leaves your device.