7.2 Navigating, Expanding, And Contracting Design Spaces

Question 1

Why are large design spaces complex?

Answer 1

Large design spaces are complex because of the combinatorial possibilities that emerge when hundreds or thousands of design variables must be assigned.

Example:

• Boeing 747 (~ six million parts)
• Chicago’s Sears Tower (100 story building)

Question 2

Explain a small or bounded design space.

Answer 2

For s**mall or bounded design spaces, the number of potential designs for the design problem is limited or small, or the number of design variables is small and take on values within limited ranges.

Example:

Design of windows in both aircraft and buildings is so constrained by opening sizes and materials that their design spaces are relatively small.

Question 3

How might a design space be expanded when it is too small?

Answer 3

Some methods of expanding a design space include:

• Literature reviews
• patent searches

Question 4

What do literature reviews determine?

Answer 4

Literature reviews determine the state of the art and identify prior work in the field.

Question 5

How are patent searches helpful?

Answer 5

Patent searches identify available technologies, to avoid “reinventing the wheel” and to leverage our thinking by building on what we already know about a still-emerging design.

Question 6

Describe patents.

Answer 6

Patents are a kind of intellectual property: Patents are awarded by the U.S. Patent Office (USPTO) and credit patent holders for having invented devices or discovered new ways to do things.

Question 7

What are the two kinds of patents that the USPTO awards?

Answer 7

The USPTO awards two kinds of patents:

• Design patents: on the form or appearance or “look and feel” of an idea
• Utility patents: for functions, that is, on how to do something or make something happen.

Question 8

What is the purpose of benchmarking?

Answer 8

Benchmarking existing products is useful when attempting to expand a design space, and helps to evaluate how well they perform.

Question 9

What is the purpose of reverse engineering?

Answer 9

Reverse engineering is useful when attempting to expand a design space, and enables visualization of how functions are performed and identification of alternate means of performing similar functions.

Question 10

How do we contract a design space when it is too large?

Answer 10

When a design space is too large:

• Check for external constraints that affect the design.
• Invoke and apply constraints.
• Freeze the number of features and behaviors being considered (e.g. color in early stages)
• Impose some order on the list.
• “Get real!” or, in other words, apply common sense to rule out infeasible ideas.

Question 11

How might we check for external constraints that affect design?

Answer 11

• Make sure the design team’s competence maps onto the design problem posed (e.g., it may be more comfortable designing tricycles than high-tech performance bikes).
• Be sure that the manufacturing capabilities are available (e.g., a team should avoid designing a bike made of composite materials if the only available manufacturing facility forms and connects metals).

Question 12

How might we impose order on our list of features and behaviors?

Answer 12

We can impose some order on the list, perhaps by harking back to data gathered during problem definition that suggests that particular functions or features are more important.