Problems with CAD – Designing Before Making


Reading – The Craftsman – Richard Sennett

Since the late nineteenth century, the blueprint was equivalent to a lawyer’s contract where the complete design concept has been presented as finished before it has been constructed. For architectural projects Computer-Aided Design is an invaluable tool for designing and presenting these large projects. However there is a disconnection between head and hand design when using CAD. Even before the advent of digital design, the design process was a combination of drawing artist’s impressions and making models. The tactile experience using pencils and pens gives the designer a greater understanding of how the finished design will appear and also greater familiarity with each brick or window that is rendered. The materiality of the bricks and the site becomes ingrained and with each site visit, you redo the drawings again. This circular metamorphosis can be eliminated with CAD and large scale, complex architectural projects could not have been made by a group of architects working by hand.

There are three failures that impede good design when using CAD

  1. Disconnect between simulation and reality
  2. Disables a relational understanding
  3. Over-determination


Peachtree Center, Atlanta (2004)

Richard Sennett has observed these three failures using CAD for an architectural project. The first issue is that the “disconnection between simulation and reality” highlighted the daily life of the environment where the building is situated. The lack of tactile experience on the part of the designer did not take into account that the summer temperature from late morning until early evening. The streets lined with cafes were not full of people enjoying al fresco drinks as the temperature for most of the daylight hours can be too hot to enjoy the ambient cafe experience.

Secondly, the ability to change the viewpoint to disguise or conceal an eyesore, for example hotel rooms overlooking an ugly car park can be presented as a minor detail and that changing the scene to something more flattering “disables a relational understanding” of the site. Disguising these issues using flattering viewpoints merely hides the problem, not eradicate them.

Sanitised “overdetermination” presents a false impression of how the building will work. The ideal rationality of CAD designed totality does not present the predictable wear and tear of the life of a building or the informality of street life and old neighbourhoods. The “crinkled fabric of buildings” allow small businesses to occupy cheap tatty spaces and the impersonal cool rationality of CAD does little to present this aspect of the evolving urban space.

The tactile act of drawing and the abuses of CAD shows that when there is a disconnect between head and hand are separate, relational understanding suffers if computers do this learning. Solutions to problems can usually be resolved on site through improvisation of the plan through “embodied knowledge” where builders use their experience and physical knowledge of the site and its problems. These manual workers did not sit in the design sessions from the start so therefore unable to point out these design issues. The separation of head and hand in this instance is not simply an intellectual issue but a social division.


Posted in Blog - MA Fine Art.

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