Topology Preserving Digitization of Physical Prototypes Using Deformable Subdivision Models

Physical prototyping is an important stage of product design where designers have a chance to physically evaluate and alter digitally created surfaces. In these scenarios, designers generate a digital model, manufacture and alter the prototype as needed, and redigitize the prototype through scanning. Despite the variety of reverse engineering tools, redigitizing the prototypes into forms amenable to further digital editing remains a challenge. This is because current digitization methods cannot take advantage of the key elements of the original digital model such as the wireframe topology and surface flows. This paper presents a new reverse engineering method that augments conventional digitization with the knowledge of the original digital model’s curve topology to enhance iterative shape design activities. Our algorithm takes as input a curve network topology forming a subdivision control cage and a 3D scan of the physically modified prototype. To facilitate the digital capture of the physical modifications, our algorithm performs a series of registration, correspondence and deformation calculations to compute the new configuration of the initial control cage. The key advantage of the proposed technique is the preservation of the edge flows and initial topology while transferring surface modifications from prototypes. Our studies show that the proposed technique can be particularly useful for bridging the gap between physical and digital modeling in the early stages of product design.