PRIN. OF DRAFTING AND SHOP DRAWINGS - OD1641 - LESSON 1/TASK 3
as they approach infinity.
Figure 35 shows a comparison between an isometric
drawing of a rectangular box and a pictorial drawing (such as an artist would draw)
of the same object; it demonstrates the distortion inherent in isometric drawings.
Note how the back corner of the isometric appears much larger than the back of the
Despite the slight distortion, isometric drawings are a
valuable way to convey technical information.
A COMPARISON BETWEEN AN
ISOMETRIC AND A PICTORIAL
The basic reference system for isometric drawings is shown in figure 36 (on the
The three lines are 120, apart and may be thought of as a
vertical line and two lines 30, to the horizontal, which means that they may be
drawn by using a 30-60-90 triangle supported by a T-square. All isometric drawings
are based on this axis system.