Manual of Engineering Drawing, 3rd Edition

Chapter 6. Three-dimensional illustrations using isometric and oblique projection

Isometric projection

Figure 6.1 shows three views of a cube in orthographic projection; the phantom line indicates the original position of the cube, and the full line indicates the position after rotation about the diagonal AB. The cube has been rotated so that the angle of 45° between side AC¹ and diagonal AB now appears to be 30° in the front elevation, C¹ having been rotated to position C. It can clearly be seen in the end view that to obtain this result the angle of rotation is greater than 30°. Also, note that, although DF in the front elevation appears to be vertical, a cross check with the end elevation will confirm that the line slopes, and that point ...