This paper describes a virtual reality application that performs fast stress reanalysis coupled with virtual reality and haptics that allows rapid evaluation of multiple designs throughout the product design process. The Interactive Virtual Design Application (IVDA) allows the engineer to interactively explore new design geometry while simultaneously examining the finite element analysis results. In the presence of other parts in the assembly, the new shape can be analyzed and modified, taking into consideration mating part fits. This approach supports concurrent product design and assembly methods prototyping. A “two-step” approach utilizing Taylor series approximations and Pre-conditioned Conjugate Gradient methods is used to perform quick reanalysis during interactive shape modification. The virtual environment provides an immersive three-dimensional workspace. Haptics are used to provide feedback of the stress gradient as the part geometry is changed, thus facilitating the designer’s understanding of the impact of shape change on product performance.