Axonometric drawing and projection includes Isometric, Dimetric and Trimetric variations. The term axonometric is derived from the greek terms 'axon' meaning axis and 'metria' meaning measuring of.
Isometric Drawing & Projection
Isometric comes from the greek origins of 'isos' meaning equal and 'metron' meaning measure. The drawing system equally divides 360° to create 3 drawing planes of 120°. Isometric drawing is the most commonly used method of axonometric drawing and projection as is the most effective to produce and easiest to understand.
Isometric projection requires the surfaces projected to the left and right of the vertical edges to be scaled. The isometric scale allows the part to be drawn with a foreshortened appearance. This reduces the drawing's overall apparent size by 22.5% compared to an isometric drawing.
Selecting an Isometric Axes
The main purpose of an isometric drawing is to provide a pictorial view that reveals as much detail as possible. This should always be considered before selecting the principal edges of a part as the isometric axes. The figures below demonstrate the various isometric views. Orientation (a) is the preferred view because of the amount of information it provides.
Drawing an isometric view
An isometric drawing can be created using an orthogonal 3rd angle projection using the following technique.
Step 1: An Orthogonal Projection or sketch
Have an orthogonal projection of the object to help understand the features of each face of the object.