Axonometric Projections:

In the particular case of axonometric projections the view plane is normal to any direction such that three adjacent faces of an object, name as a cube, are visible. In case of axonometric projections, this is not preferred to place view planes parallel to any one of the major axis. It helps in ignoring the duplication also. The view plane is placed such that it intersects at least along two of the major axes. Lines which are parallel in the world coordinate system of a three-dimensional object are projected to as parallel lines just to the view plane. Length of a line that is parallel to the view plane is also maintained. All other lines along with the same axis maintain only their proportion and are foreshortened equally. Following are some salient features of the axonometric projections.

1.      View planes normal for an axonometric view is generally not parallel with a major axis.

2.      Lines of a three-dimensional object that are parallel in the WCS are projected like parallel lines.

3.      Line length is maintained just for lines parallel to the view plane.

4.      Relative lengths of the originally parallel lines remain constant.

5.      Least restrictive (arbitrary rotation in any order around one or all axes followed by parallel projection onto z = 0 plane).

Furthermore, axonometric projections are divided into three classes, that means isometric, diametric, or trimetric projections based upon the number of major axes, which are foreshortened equally.