Isometric is a mathematical method of constructing a 3 dimensional object without using perspective. Isometric was an attempt to make drawings more realistic. The mathematics involved mean that all lengths when drawn at 30 degrees can be drawn using their true length (in other words lines aren't shortened as with oblique drawings). An isometric drawing shows two sides of the object and the top or bottom of the object. All vertical lines are drawn vertically, but all horizontal lines are drawn at 30 degrees to the horizontal. Isometric is an easy method of constructing a reasonable '3 dimensional' images.


Isometric Example Box


Below is an object showing how the isometric lines are formed.


Isometric Example Box


To draw in isometric you will need a 30 / 60 degree set square (As illustrated). These can be purchased from all major stationary stores.


To help you it is also possible to use a grid paper underlay sheet to act as a guide for your drawing, this is shown below.


Isometric grid


Here are some examples drawn using an isometric grid:


Isometric grid examples


Isometric grid examples


Isometric grid examples


Isometric grid examples


The steps below show how to draw a box in isometric.

Initially when you first start using isometric it can be useful to use a simple box as a basic building block a guide to help you draw more complicated shapes.


1. Draw the front vertical edge of the cube.


1. Draw the front vertical edge of the cube.


3. Draw in the back verticals.


4. Drawn in top view with all lines drawn 30 degrees to the horizontal


Drawing more complicated shapes


Orthographic Angle Bracket


This simple example shows you how you can use a box to help you accurately draw a more complicated shape. The object we are going to draw is L-shaped as illustrated by the engineering drawing (above)


The first step is to draw our guide box. This box is the size of the maximum dimensions.
In this case, 50 mm long, 25 mm wide, and 50 mm high. Draw the box in very lightly.
When we have the final shape we can darken the lines.


To get the L-shape we need remove an area from this box.
Draw a box 40 x 10 x 50 mm, the shape that needs to be removed
from the box to create the shape we require.


The finished shape


Circles in isometric don't appear circular. Instead they are skewed and are actually elliptical. There are several methods of constructing circles in isometric. By far the easiest method is to use an isometric circle template which can be bought from most good art shops. These templates contain a number of isometric circles of various sizes. If you decide not to buy a template then you must construct a circle.


Constructing an isometric circle


1. First draw an isometric square. Draw in the diagonals, a vertical and a line
at 30 degrees from the midpoint of the sides as illustrated


2. Place your compass point on the intersection of the horizontal line and the vertical line.
Draw in a circle which touches the edges of the box.


3. To draw the next section of the isometric circle place your compass point
on the corner of the isometric 'square' and draw in the arc as illustrated.


4. Complete the circle using the appropriate technique.