Test Driven Design

Test driven design refers to a design process that performs tests and rapid prototypes on an early and ongoing basis - prior to an actual build. This can be done in various ways:

1. Subject Matter Expert review
2. Partial Prototypes - Building out small components at a time instead of a whole machine at a time.
3. Module Based Design - Breaking artifict into smaller modules and prototyping individual modules
4. Scale models - this may be done by wood, paper, or other models - such as 3D printing, laser cutting for folded (LifeTrac tubing) or stacked (architecture) paper pieces, or many other models
5. Doing extra calculations or simulations in software or in Hardware-in-Loop systems
6. Visualizations, 3D renderings, motion analysis

See analogue in software - http://en.wikipedia.org/wiki/Test-driven_development