Perspective Box Generator
Boxes, cylinders and scale figures at real sizes, on a real grid. Set the metres, choose the lens, export.
Boxes at real sizes on a real grid
Every object here is a real-world size in metres, placed on a ground plane seen through a real lens. Add a one-metre crate, a door, a car, or a person; move it nearer or further; rotate it; change the lens; and watch how its edges run to the vanishing points and how its size changes against the grid. Then export the construction as a transparent layer and draw the real thing on top.
What the objects are for
Box is the general-purpose form: buildings, furniture, vehicles, rooms. Its base diagonals are drawn faintly so you can find its centre and subdivide it. Cylinder gives you the ellipses of columns, cans, wheels and cups, which are the hardest thing to freehand in perspective; note how the ellipse opens up as it moves below the eye line. Person is a proportional scale figure, 1.75 m by default, with a tick at eye height so you can see it sit exactly on the horizon at any distance.
Reading the result
The horizon (dashed) is the camera's eye level. Anything at 1.6 m height touches it. Boxes below the horizon show their tops; boxes above it show their undersides. When two boxes have the same rotation their edges share vanishing points; rotate one and it gets its own pair. At wide lenses (24 mm and below) objects near the frame edge stretch; that is correct, and it is why architectural work usually sits at 28–35 mm.
Getting it into your app
Export a transparent PNG (2× or 4×) or an SVG with every edge as a vector path. In Procreate or Clip Studio, paste it as a layer, drop the opacity, lock it, and draw. Every setting, including the objects, is stored in the page link, so a set-up can be shared or bookmarked.
Related
The 2-point grid is the same camera without objects; the figure height calculator gives the numbers behind the scale figure; how to draw perspective explains the box construction by hand.
Questions
What is a perspective box?
A box drawn in correct perspective is the starting point for almost everything else: buildings, furniture, vehicles and figures are all boxes first, then carved. Getting the box right (two vanishing points on the horizon, verticals parallel unless the camera tilts) fixes most drawing problems before they start.
Are the sizes real?
Yes. The ground grid is one metre per square, the camera is 1.6 m above the ground, and every object is placed and sized in metres. A 2.1 m door and a 1.75 m person come out in the right proportion at any distance and lens.
Can I make a 3-point box?
Switch the camera to tilted. The boxes' verticals then converge toward a third vanishing point above or below, and you can set the tilt with the vertical-rotation slider or by dragging.
How do I rotate an object?
Each box and cylinder has a rotation field in degrees. Rotating a box changes which pair of vanishing points its edges use; at 45° to the camera both faces are equal.