Research On Motion Blending Oriented To Heterogeneous Skeletons Of Animation Characters

Traditional motion blending methods can only process motion data of the homogeneous characters, which make existing motion database can not be reused fully. In order to break through the limitation of skeleton structure of characters and synthesize diverse motion data, a new motion blending method oriented to heterogeneous skeletons is proposed. Based on the summary of the differences and characteristics of motion data, motion retargeting technique for heterogeneous skeletons is introduced, and then a complete solution to motion blending in heterogeneous skeletons is established, at last motion synthesis of animation characters is achieved.The main work of this dissertation is listed as follow:(1) A method of motion retargeting based on key-postures mapping is put forward. With consideration of the characteristics of high-dimensions of original motion data, principal component analysis is applied to reduce the dimensions and obtain the main features of motion sequence. Posture clustering is applied to extract key-postures of motion sequence. According to the mapping relation between the original skeleton and target skeleton, the key-postures of target character are built automatically. At last, motion sequence is reconstructed by multivariate interpolation method.(2) A method of motion blending based on dynamic time warping(DTW) is explored. Motion data is represented by quaternion. On this basis, a method of calculating similar frames is defined, and a curve for time warping is constructed to warp motion sequence. Local posture blending is achieved by quaternion spherical interpolation, and the trajectory of root joint is reconstructed, then the character motion under world coordinate is synthesized. Finally, a new method of motion editing based on inverse kinematics and interpolation is established, in order that motion clip can be modified and corrected fast. The experiments results demonstrate the excellent interaction and satisfactory vision effect of this algorithm.(3) On the basis of the above work, a prototype system of motion blending is implemented. By analysis of animation characters, skeleton frames and data structure of motion sequence are defined. Then some related functional modules are achieved, including skeleton animation files parsing, motion data exporting and importing, and real-time interactive motion editing.