This paper presents a technique for adapting existing motion of a human-like character to have the desired features that are specified by a set of constraints. This problem can be typically formulated as a spacetime constraint problem. Our approach combines a hierarchical curve fitting technique with a new inverse kinematics solver. Using the kinematics solver, we can adjust the configuration of an articulated figure to meet the constraints in each frame. Through the fitting technique, the motion displacement of every joint at each constrained frame is interpolated and thus smoothly propagated to frames. We are able to adaptively add motion details to satisfy the constraints within a specified tolerance by adopting a multilevel B-spline representation which also provides a speedup for the interpolation. The performance of our system is further enhanced by the new inverse kinematics solver. We present a closed-form solution to compute the joint angles of a limb linkage. This analytical m...

Animating human-like characters is a recurring issue in computer graphics. Recently, capturing live motion has become one of the most promising technologies in character animation. Due to the success of this technology, realistic and highly detailed motion data are rapidly spread in computer graphics applications. Crafting animation with such data requires a rich set of specialized tools such as interactive editing, retargetting, blending, stitching, smoothing, enhancing,up-ing,W4G6 downsampling and so on. With those tools, animators combine motion clips together into animations of arbitrary length with great variety in character size, environment geometry, and scenario. A typical process of producing animation from live-BE5P7WM data includes three major steps: The first step is to filter the raw input signal received from a motion capture system to obtain smoother, pleasing motion data. The next is to adapt the motion data to fit into a specific character or a virtual environment that...

Abstract In this paper, a new inverse kinematics (IK) solver is introduced which can solve a multiple constrained 12-DOF human limb analytically with the joint limits taken into account. By combining the IK solver with multilevel curve fitting technique, we enable the user to specify constrains on few keyframes through a mouse or keyboard, then the joint angles of the figure at each keyframe are automatically calculated by the IK solver, and the motion displacement of every joint at each constrained frame is propagated to neighboring frames. The motion editing method presented here is fast and convenient for creating various new realistic human motions from captured motion clips. We demonstrate that our technique can be used for retargeting motion to new environments. Furthermore, the graphic user interface we developed is friendly and convenient for manipulation, and our algorithm is rather fast.