Existing 3D sketching methods typically allow the user to draw in empty space which is imprecise and lacks tactile feedback. We introduce a shape-stamping interface where users can model with tangible 3D primitive shapes. Each of these shapes represents a copy or a fragment of the construction material. Instead of modeling in empty space, these shapes allow us to use the real-world environment and other existing objects as a tangible guide during 3D modeling. We call this approach Situated Modeling: users can create new real-sized 3D objects directly in 3D space while using the nearby existing objects as the ultimate reference. We also describe a two-handed shape-stamping technique for stamping with tactile feedback. We show a variety of doit-yourself furniture and household products designed with our system, and perform a user study to compare our method with a related AR-based modeling system.

Although there is an abundance of 3D models available, most of them exist only in virtual simulation and are not immediately usable as physical objects in the real world. We solve the problem of taking as input a 3D model of a man-made object, and automatically generating the parts and connectors needed to build the corresponding physical object. We focus on furniture models, and we define formal grammars for IKEA cabinets and tables. We perform lexical analysis to identify the primitive parts of the 3D model. Structural analysis then gives structural information to these parts, and generates the connectors (i.e. nails, screws) needed to attach the parts together. We demonstrate our approach with arbitrary 3D models of cabinets and tables available online.