perspective+drawing.

Perspective Drawing

A technique of depiciting volumes andspatial relationships on a flat surface.

When someone looks at an object, there is a line of sight from every point on the object ot the eye. imagine a plane, such as an empty canavas, that intersects the line in sight. the points of intersection on the plane make up the image of the object, and the image is said to be projected onto the "picture plane"