1. Engineering Graphics Isometric Axes height 30 degrees width depth
Width and depth axes are sketched at 30 degrees above or below horizontal.
Height axes is vertical.
width
depth

2. for Isometric Sketching
5 by 3 Rule
for Isometric Sketching
5 Squares
Engineering Graphics
3 Squares
To maintain parallelism of lines count 8 squares left/right and 5 square up/down to establish lines isometric slope.
The 8x5 rule provides a good approximation for 30 degrees above or below the horizon.
Keeps Lines at Approx.30 Degrees from horizontal

3. Engineering Graphics Common Isometric Views
The standard isometric view shows the front, top , and right side view of the object (similar to the dog house) but this may be altered to show the object as it is normally viewed (a birdhouse is often viewed from the bottom since it may be located above your line of sight).

4. Steps to Produce Isometric Pictorials
Engineering Graphics
Isometric axes for objects width and depth are at 30 degrees above/below the horizon.
Steps are similar to those used in creating oblique pictorials.

5. Engineering Graphics Isometric Ellipses
Since none of the isometric surfaces are normal to your line of sight they all produce distorted (not true-shape) images-- circles are shown as ellipses etc.
It is important to be able to represent isometric circles or ellipse on all isometric surfaces.

6. Isometric Cylinders and Holes
Look-through
Engineering Graphics