The methods of rapid prototyping are ideally suited to rehabilitation devices. Because each person requires unique performance and function in a rehabilitation device, devices specific to each person must be rapidly designed and produced. This project is investigating a completely integrated approach to the design and prototyping of passive mechanical rehabilitation devices. The approach involves: the quantitative assessment of the form and performance of human limbs; the design of the assistive device; evaluation of the device using virtual prototyping; feedback from the consumer and therapist; actual prototyping of the device; evaluation of the function and performance of the device; and redesign based on performance. The contributions of the product include: the development of new computer-based tools for the assessment of human performance; a manufacturing technique for a new class of hyperelastic materials; the integration of tools into a rapid prototyping system for rehabilitation devices; and development of mechanisms for systematic evaluation of the final product.