Research Of Motion Retargeting Based On The Motion Constraints

With the development of Motion Capture System, Character Animation has made great progress. It can produce motions with lower costs and higher efficiency. But the original data can not be directly mapped on to the animation character which is different limbs length from the actors’. So the hot spot studied by many scholars is how to reuse the data properly, namely, how to modify and edit the original motion capture data in order to eliminated the distortion by the retargeting and meet with the demands for different characters.In this paper, the human body tracking system is built based on wireless and inertial sensor first of all. The system imitates the tracking function for9degrees of freedom (DOFs) and finally realizes the tracking effect by driving the virtual3D digital arm.Moreover, Basing on the capture data of human motions, this dissertation commits itself to researches on the motion retargeting. It includes geometries based technique, space-time constraints based technique and physics based technique. Only using the kinematics’methods, modeling will be easy but the synthetic motion maybe lack of physical realistic; only using dynamic methods, the synthetic motion maybe satisfy the physical realistic requirement but the solving progress is complex and time consuming. This paper presents a motion retargeting method by combined the displacement mapping and physical constraints based technique. This thesis constructs resolver of balance constraint, torque constraint and movement constraint firstly, and then corrects the displacement trajectory. Input the source motion data and require the target motion data. In order to solving highly nonlinear constraints, this paper uses Unscented Kalman Filter (UKF) algorithm which can estimate the optimal parameters from a series of motion data. And in order to meet our requirements, the paper regulates the target motion trajectory by B-spline curve fitting. So the generated movement not only retains the original of motion characteristic, it shows the good authenticity.Based on motion data of BVH files from CMU’ database, Motion retargeting platform is built using Motion Builder and3DS Max. Now it can carry out motion retargeting among vary models and make a good preparation for the further research of motion retargeting.