Perspective: One-Point, Two-Point and Three-Point
Perspective questions test whether you can place a horizon, choose the right system for the view, and keep every receding line honest. Marking is usually on construction accuracy before finish.
Core rules
- The horizon line is the eye level of the viewer; it moves up or down with the viewer's height, not with the object.
- All receding parallel lines meet at a vanishing point on the horizon line.
- One-point: the front face of the object is parallel to the picture plane, so only depth lines recede to a single point, usually placed near the centre of vision.
- Two-point: the object is seen corner-on, so two sets of horizontals recede to a left and a right vanishing point. Verticals stay vertical.
- Three-point: used when looking up or down at a tall block; the third vanishing point lies far above or far below the horizon, and verticals converge towards it.
- Keep vanishing points far apart. Close points produce violent distortion.
- An ellipse in perspective is not a symmetrical oval: its centre lies nearer the far edge.
Worked example
A box in two-point. Draw the horizon at about two-thirds height. Place the left vanishing point well outside the left edge of the paper and the right one well outside the right edge. Draw the nearest vertical edge, taller than the ground line it stands on. From its top and bottom, draw faint lines to both vanishing points. Choose a depth along each receding line and draw the two back verticals, then close the top and bottom faces to the opposite point. The reasoning: choosing depth after the vanishing lines exist keeps the box in proportion and prevents the back corner drifting.
Traps
Vanishing points placed too close, a tilted horizon, leaning verticals in a two-point drawing, mixing one-point construction into a rotated box, all parallel lines not meeting at the same point, and ellipses drawn as flat ovals.