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Axonometric Drawing

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.

(a)

(b)

(c)

(d)

 

(e)

(f)

(g)

(h)

 

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.

 

Step 2

Prepare your drawing board, tee square, and 30/60 set square.

Step 3

Using your tee square and an isometric set square draw a line at 30°. Do not worry about measuring the lines. Best guess the measurement required. It is important to ensure that you draw as lightly as possible. Ideally, your line work should not be able to be seen to anyone standing 1-2 meters away from you.

 

Step 4

Using a ruler, measure and mark the depth of the object. Mark the line by accurately placing the pencil at the measurement and then spin and lift the pencil.

Step 5

Rotate the Set Square and draw a vertical line to represent the height of the object.

 

Step 6

Complete the isometric box by drawing the back edges of the object.

Step 7

You can now begin to draw in the detail of the object.

 

Step 8

Refine the drawing by completing any fine details. Erase any construction lines used to build the drawing..

Step 9

Spatially profile the drawing by thickening the outer edges of the object. These represent the edges where the object's surface cannot be seen by the viewer.

 

Dimetric Projection

Trimetric Projection