Axonometric projection-
Axonometric projection  is a parallel projection technique used to create a pictorial drawing of an object by rotating the object along one or more of its axes relative to the plane of  projection (or the picture plane). Axonometric projection is one of the four principal projection techniques: multiview, axonometric, oblique and perspective projection (Figure-1). In multi view, axonometric, and oblique projections, the observer is theoretically infinitely far away from the projection plane. In addition, the lines of sight are parallel  to each other and perpendicular to the plane of projection.  The main difference between a multiview drawing and an axonometric drawing are that, in a multiview, only two dimensions of an object are visible in each view and hence more than one view is required to define the object. In an axonometric drawing, the object is rotated about an axis to show all three dimensions, and only one view is required.

Figure 1. illustrates the four principle projection techniques.