A method of evaluating a product for use on a body used to develop a preferred product configuration using a computer-based virtual product development and testing system. A virtual wearer sub-model is created of the body and a virtual product sub-model is created of a product for use on the body. An environment sub-model is generated so that environmental factors affecting the product or the body are also used in designing or evaluating the product. Instructions defining how the wearer sub-model, the product sub-model and the environment sub-model interact are introduced in an interaction model. The sub-models and the interaction defined by the interaction model are then combined to create a virtual use model simulating the use of the virtual product sub-model by the virtual wearer sub-model. The use model determines the forces, deformations and stresses caused by movement and interaction between the virtual wearer sub-model and the virtual product sub-model using numerical method analysis. The results of the use model are analyzed to evaluate the performance of product features embodied in the virtual product sub-model such as when positioned on a virtual wearer and exposed to typical movements or forces. The analysis evaluates the performance of at least one product feature of the product and/or wearer body.