The dangers of drawings

Of course the ‘greater perceptual span’ of design 
by drawing as opposed to vernacular design enabled 
greater rates of experimentation and thereforeincreased 
the risk of failure. 

The more we innovate from one design to another the less
 reliable will be the designer’s knowledge of ‘what might work’.
But there is another great problem with the process of design 
by drawing.
The drawing is of course merely one form of representation 
of some features ofthe object that are not yet made. 
Every form of representation has its own characteristics and 
therefore strengths and weaknesses in representing imagined
objects and conjuring up in our minds the experience of those
 objects in real use. 
The drawn image has conventions of views but all those 
conventions are essentially variations on a theme of geometrical 
and spatial relations  of one sort or another. 
In other words the drawing is good at representing how 
the object will appear to the eye and how the various 
constituent parts of it are  related in space. 
While this may in itself be valuable knowledge it is far from being
a complete and comprehensive representation of the features of
 many commonly designed objects which really matter to their eventual
 users.