In this paper we present an intuitive tool suitable for 2D artists using touch-enabled pen tablets. An artist-oriented tool should be easy-to-use, real-time, versatile, and locally refinable. Our approach uses an interactive system for 3D character posing from 2D strokes. We employ a closed-form solution for the 2D strokes to 3D skeleton registration problem. We first construct an intermediate 2D stroke representation by extracting local features using meaningful heuristics. Then, we match 2D stroke segments to 3D bones. Finally, 3D bones are carefully realigned with the matched 2D stroke segments while enforcing important constraints such as bone rigidity and depth. Our technique is real-time and has a linear time complexity. It is versatile, as it works with any type of 2D stroke and 3D skeleton input. Finally, thanks to its coarse-to-fine design, it allows users to perform local refinements and thus keep full control over the final results. We demonstrate that our system is suitable for 2D artists using touch-enabled pen tablets by posing 3D characters with heterogeneous topologies (bipeds, quadrupeds, hands) in real-time. 
Artist-oriented 3D character posing from 2D strokes