Two-point perspective is when the planes of the object are not parallel ("skewed") in relation to the picture plane. As with one-point perspective, the viewer's eye level is established by drawing a horizon line. Two vanishing points are located on either side of the object, most often placed beyond the borders of the picture space. The solid's closest corner is drawn and the receding planes established by following the orthogonals from the ends of this edge to the vanishing points. In two-point perspective all lines except the verticals, which remain parallel, can be traced back to these points.
Linear perspective does not truly mimic the way in which we actually experience objects in space. It presumes that we do not move our eyes, head or body, and ignores such things as binocular vision, parallax and atmospheric distortion.
Roll the mouse over the exercise screen above to see how two-point perspective changes the box when it is in different positions. Click on the box to disable or enable its movement. Click on the Linear, Solid, or No Lines buttons to view the box with or without shading or the perspective lines.