Orthographic Projections, ContinuedMultiviewprojectionsMultiview projections are the second major subdivision of orthographicprojections.Principal viewsThere are six principal views in a multiview orthographic projection. Theseare the front, back, top, bottom, and left- and right-side views. Of theseviews or planes, three are referred to as primary planes of projection(vertical, horizontal, and profile). Most objects are adequately representedby the three primary planes.Angles ofprojectionThe primary planes intersect each other at right angles. The angles betweenthe horizontal and vertical planes are described as first, second, third, andfourth angles of projection. In theory, you can place an object in any ofthese angles of projection and draw or project its image onto the projectionplanes, which in turn could be rotated onto the plane of your drawing paper.Only first- and third-angle projection have a practical application today.Figure 6-23 shows the angles of projection in a multiview projection.Figure 6-23.—Angles of projection in multiview projections.Continued on next page6-28