Animated Character Rigging Expression Transfer
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Solution Overview
Problem
The current process of defining skin weights for animated character rigs is time-consuming and error-prone, requiring manual replication of basic expressions across multiple rigs, which is inefficient and prone to errors.
Innovation Solution
A method for automatically transferring expressions and skin weights between rigs by calculating joint position offsets, applying scaling transformations, and using Radial Basis Function splines for interpolation, allowing for consistent joint positioning and skin weight mapping across different skin meshes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual replication of basic expressions is performed across multiple rigs, then consistency of character interface is achieved, but time consumption and skill requirement increase significantly
Solution Approach 1:
The patent implements automatic copying of skin weights and joint positions from a source rig to target rigs through computational algorithms. The system calculates skin weights for target rigs by transforming and adapting the source rig's skin weight data, eliminating manual replication while maintaining consistency across different character rigs.
2Manufacturing precision
If manual skin weight definition is performed for each rig, then accurate skin deformation is achieved, but the process becomes highly time-consuming and skill-dependent
Solution Approach 1:
The system enables self-service by automatically calculating and assigning skin weights for target rigs based on source rig data. The computational algorithms perform the skin weight definition task autonomously without requiring manual intervention, thereby maintaining accuracy while dramatically improving productivity.
Solution Approach 2:
The patent transforms skin weight parameters from manually defined values to computationally derived values. By changing the method of parameter definition from manual input to algorithmic calculation, the system maintains deformation accuracy while reducing time consumption and skill requirements.
3Stability of the object's composition
If static skin weights are used for all expressions, then skin topology consistency is maintained, but adaptability to different rig configurations is reduced
Solution Approach 1:
The patent introduces dynamic skin weight assignment where skin weights are calculated and adapted for each target rig based on its specific joint configuration and scale. This dynamic approach allows the same source rig data to be effectively adapted to multiple different rig configurations while maintaining skin topology consistency through the transformation algorithms.
Data Source
AI summary
Computer-implemented methods and computer program products for automatically transferring expressions between rigs with consistent joint structure, and for automatically transferring skin weights between different skin meshes based on joint positioning. A method is provided for transferring an expression between a plurality of source rigs and a target rig, where each rig characterizes an animated character, and each rig, in turn, is characterized by a set of joints and a skin mesh having a plurality of vertices, with each vertex characterized by a matrix of weights relating a response of the vertex to movement of associated joints. A set of offsets is calculated of joint positions of a goal expression of each source rig relative to a neutral expression of the source rig. A scaling transformation is then applied to the set of offsets to produce a scaled set of offsets, which are added, in turn, to a neutral expression of the target rig. Methods are also provided for transferring a set of skin weights between the source rigs and the target rig.