A new mathematical formulation will be investigated to model concurrent decision-making in design. Parametric models, initially developed solely to study changes in optimized quantities as problem parameters are locally perturbed, will now be examined in a broader design and manufacturing context. Motivation is provided by recent results on large parameter deformations in the field mathematical optimization. The research effort examines the theoretical properties of a new formulation, and examines the use of two different algorithms to solve the models numerically. Successful treatment of the research case studies will show how the concept of model optimality integrates the design and manufacturing decisions in concurrent engineering.