Character Extremity Action Modeling via End-Position Coordination
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Solution Overview
Problem
Current computer graphics modeling of character actions often results in unnatural extremity movements due to independent joint motion calculations, requiring complex mathematical models and excessive variables to achieve natural motion.
Innovation Solution
An action modeling device that determines the position of a character's extremity by using a first joint as a reference, with a second joint in the middle, allowing rotation within a predetermined angle range, thereby preventing unnatural movements and reducing the number of variables needed for modeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If motion range models are set independently for each joint, then the modeling calculation is simple, but the end portions of extremities move to unnatural positions
Solution Approach 1:
The extremity is divided into multiple segments (first extremity segment between first joint and second joint, second extremity segment between second joint and end portion). Each segment has its own motion range model, but the segments are coordinated through the shared second joint. This segmentation allows independent calculation simplicity while ensuring natural positions through inter-segment coordination.
Solution Approach 2:
The patent changes the parameter representation from independent joint angles to end portion position coordinates. By determining the motion range of the second joint based on the calculated position of the end portion rather than independent joint angle specifications, the system achieves both calculation simplicity and natural position accuracy.
2Manufacturing precision
If the number of variables is increased to realize more natural motions, then the naturalness of action improves, but the mathematical model becomes complicated
Solution Approach 1:
The patent extracts and removes the unnecessary complexity of independent joint angle variables. Instead of using multiple joint angle variables that create complicated mathematical models, the invention extracts only the essential end portion position coordinates and derives joint motion ranges from these positions, simplifying the mathematical model while maintaining natural motion accuracy.
Solution Approach 2:
The patent inverts the conventional approach by not specifying joint angles directly to achieve natural motion. Instead, it specifies the end portion position first, then derives the joint motion ranges from these positions. This inversion reduces the number of variables and simplifies the mathematical model while achieving the same natural motion effect.
3Manufacturing precision
If joint motions are restricted due to influence of adjacent joints, then the realism of action improves, but the independent calculation for each joint becomes invalid
Solution Approach 1:
The patent merges the motion range determination of adjacent joints through the shared second joint. The motion range of the second joint is determined by considering the position of the end portion, which inherently accounts for the influence of the first joint. This merging ensures realistic action while maintaining the validity of independent calculation for each joint segment.
Data Source
AI summary
Actions of a player character in a virtual three-dimensional space are determined for each of the extremities. The position of the end portion of each extremity is determined in the local coordinates of the extremity, with the fixed portion being the reference position. The position of the end portion is determined within a pre-defined range of access, then the joint angle of the intermediate portion is fixed, and the position of the intermediate portion is determined from the angle of rotation about the axis connecting the fixed portion and the end portion. The position of the intermediate portion is determined as angular information within the range of motion of the intermediate portion, which is defined in accordance with the position of the end portion. The shape of each extremity of the character is determined by the positional information about the end portion and the angular information about the intermediate portion.