CAVALIER PROJECTION is a form of oblique projection in which the projection lines are presumed to make a 45-degree vertical and a 45-degree horizontal angle with the plane of projection. Assume that in figure 5-47 the line XX' represents a side-edge view of the plane of projection, and that the square ABCD represents a side of a cube, placed with its front face parallel to, and its top face perpendicular to, the plane of projection. You can see that the projected lengths of AB and AD are the same as the actual lengths.

Now assume that the line XX' in figure 5-47 represents a top-edge view of the plane of

Figure 5-46.Oblique and orthographic projections of the same object.

Figure 5-47.Angle of projection lines in a cavalier projection.

projection, and that the square ABCD represents the top of the cube. You can see again that the projected lengths of AB and AD are the same as the actual lengths of AB and AD.

In a cavalier projection, then, any line parallel to or perpendicular to the plane of projection is projected in its true length. Figure 5-48 shows a cavalier projection of the cube shown in figure 5-47. You start by drawing the axis, which consists of the front axes OA and OB and the receding axis OC. The front axes are always perpendicular to each other; the receding axis

Figure 5-48.Cavalier projection of a cube. 

may be drawn from O at any convenient angle. All three are equal in length, the length being the length of an edge of the original cube (which may be scaled down or up if the drawing is made other than full scale). After you draw the axis, complete the projection by drawing the required parallel lines. All the edges shown in the projection are, like the edges on the original cube, equal in length.