A SmartPen for 3D interaction and sketch-based surface modeling

This paper presents an innovative, portable, and low cost system for fast and interactive design of sketched models using 3D curve networks. The system is based on a stereo camera and a wireless pen-shaped device, called the SmartPen, which can be extended or bent to facilitate concave objects' acquisitions. Its tip position is tracked in 3D and used to trace the style lines of the object to be modeled in the virtual space. Starting from the 3D irregular curve network, progressively drawn by the user, a new Sketch-based Modeling Framework automatically creates the inferred 3D virtual model. The interactive system integrates perceptual and conceptual modeling, allowing both for the reconstruction of existing objects via user-drawn strokes on the physical object and for free-hand strokes which together contribute to realize the desired 3D curve network. Real-time reconstruction of the sketched surface interpolating the 3D curve network is obtained through an interactive curvature-based optimization approach which determines the smooth subdivision surface that best fits the traced 3D curve network.