Perspective Drawing is used by artists to give the illusion of space and distance.A perspective drawing is a form of pictorial drawing.A perspective drawing utilizes either one, two or three points to where the receding lines will vanish. These vanishing points are placed along a horizontal line called a horizon line. No longer will the receding lines be parallel to each other as in oblique or isometric drawings.
Orthographic Projection is a way of drawing an 3D object from different directions. Usually a front, side and plan view are drawn so that a person looking at the drawing can see all the important sides. Orthographic drawings are useful especially when a design has been developed to a stage whereby it is almost ready to manufacture.