A projection plane, or plane of projection, is a type of view in which graphical projections from an object intersect. Projection planes are used often in descriptive geometry and graphical representation. A picture plane in perspective drawing is a type of projection plane.
With perspective drawing, the lines of sight between an object and a picture plane return to a vanishing point and are not parallel. With parallel projection the lines of sight from the object to the projection plane are parallel.
Perspective projection of triangle ABC on plane Π from point S.
Axonometric projection on projection plane Π
A cube in two-point perspective
Simulated rays of light travel from the object, through the projection plane, and to the viewer's eye or camera. This is the basis for graphical perspective.