Orthographic projections produce front, top, and side views of an object by projecting planes onto the object from different angles. There are three principal planes - the vertical plane, horizontal plane, and profile plane - that are perpendicular to each other. The front view is seen on the vertical plane, the top view on the horizontal plane, and the side view on the profile plane. Isometric projections can be produced from two or more orthographic projections by drawing the real figure at a projection angle.