The Design Spiral
My personal implementation of the concept of iterative design, first introduced to me by Prof. Joel Burdick and Dr. Mike Mello in 2014. Expanded, yet also constrained, by Derek Lay in 2017.
The best use of the first loop defines the interfaces of the design. Interfaces are how the design interacts with the other components of its system, and potentially the outside world. They are the most important constraints, and should be identified first to guide the design process to an abstract solution space with the maximum number of possible solutions.
The First Loop: Interfaces
The middle loops are not numbered because each design is different, and has different constraints. For mechanical designs, these constraints could be clearance around other parts, weight, strength, rigidity, etc. Each of these design loops brings the design further from an abstraction and closer to a real solution.
The Middle Loops: Physical Constraints
The penultimate design loop provides a solution that meets all design criteria, but to my continued dismay, imagined designs do not suddenly pop into existence. The final design loop brings the solution to a state that can be made real. Ideally, the design is then manufacturable through any method, but that is almost never the case, and this final loop dictates how to manufacture the design.
