Molding is a popular method for the mass production of objects. Essentially, two (or more) mold pieces are fit together, leaving the shape of the desired object as a hole. During fabrication, a fluid is introduced into this cavity and is allowed to harden. Once the fluid has solidified, the pieces of the mold are removed, leaving behind the molded object. While the process is fairly simple, creating the mold to produce an object is extremely difficult, and a multitude of considerations go into its creation.
How should the object be oriented and divided to ensure that the pieces of the mold can be removed? If the object should be hollow, how should it be decomposed into pieces? Figures with loops or holes add further complications, as do aesthetic considerations such as avoiding a parting line through a face. In mass fabrication, the high costs of the initial mold design are offset by the low per-unit cost of production. For a small-scale designer or a novice interested in experimenting with injection molds, hiring a professional mold designer is impractical, and creating the molds unaided is infeasible. Similarly, 3D-printing the desired number of objects would be far too time- and resource-intensive.
CoreCavity, a new interactive design tool, allows users to quickly and easily design molds for creating hollow, freeform objects. Given a 3D scan of an object, the software analyzes the object and creates a thin shell — essentially, a hollow version of the object in which particularly small gaps are considered solid. The software then proposes a decomposition of the object into pieces; each piece will be created by one mold, then joined together at the end. Moreover, the program is able to suggest slight modifications to the original design; for instance, to eliminate tiny hooks that might complicate unmolding. The user can adjust the decomposition simply by clicking and choose to accept or reject any proposed modifications. When the user is satisfied, the software automatically produces the mold templates, which can then be 3D-printed and used for molding.