Encore: 3D printed augmentation of everyday objects with printed-over, affixed and interlocked attachments

One powerful aspect of 3D printing is its ability to extend, repair, or more generally modify everyday objects. However, nearly all existing work implicitly assumes that whole objects are to be printed from scratch. Designing objects as extensions or enhancements of existing ones is a laborious process in most of today's 3D authoring tools. This paper presents a framework for 3D printing to augment existing objects that covers a wide range of attachment options. We illustrate the framework through three exemplar attachment techniques - print-over, print-to-affix, and print-through. We implemented these techniques in Encore, a design tool that supports a range of analysis with visualization for users to explore design options and tradeoffs among these metrics. Encore also generates 3D models for production, addressing issues such as support jigs and contact geometry between the attached part and the original object.