3D Curve Rigging for Non-Rigid Object Animation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rigging non-rigid structures in computer animation is challenging due to the lack of predefined joints or control handles, making it difficult to animate objects that bend or flex at any point, such as blades of grass or octopus tentacles, as existing methods require manual definition of control variables for each knot primitive.
Innovation Solution
A 3D curve rigging element is defined using a plurality of knot primitives, where each primitive corresponds to a position in the 3D scene and animation control attributes, allowing for dynamic generation of missing attribute values based on neighboring primitives, enabling flexible and efficient animation of non-rigid objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual definition of control variables is required for each knot primitive, then animation precision is maintained, but device complexity and time consumption increase significantly
Solution Approach 1:
The rigging system divides the non-rigid object into discrete knot primitives along a curve, where each knot can be independently controlled. This segmentation allows animators to define control variables only for specific key knots rather than every point, reducing complexity while maintaining precision where needed.
Solution Approach 2:
The system automatically interpolates and generates control variable values for undefined knots based on the defined control variables and the curve's geometric properties. This self-service mechanism eliminates manual definition for every knot while preserving animation precision through mathematical interpolation.
2Measurement precision
If control variables are defined for all knot primitives, then animation control accuracy is improved, but productivity decreases due to extensive manual input required
Solution Approach 1:
The system allows animators to define control variables for only a subset of knot primitives (partial action) rather than requiring complete manual definition. The remaining control variables are automatically generated through interpolation, maintaining accuracy while dramatically improving productivity by reducing manual input.
Solution Approach 2:
The system pre-calculates and stores the geometric properties of the curve (tangents, curvatures, distances between knots) during the rigging setup phase. These pre-computed values are then used during animation to quickly generate control variable values without real-time calculation overhead, improving both accuracy and efficiency.
3Ease of manufacture
If existing rigging methods are used for non-rigid structures, then implementation is straightforward for rigid objects, but adaptability to non-rigid structures is limited
Solution Approach 1:
The rigging system uses a universal curve-based representation that can model both rigid and non-rigid structures. By representing the object as a parametric curve with knot primitives, the same framework adapts to various non-rigid forms (tentacles, ropes, fabric) while maintaining the procedural generation approach that ensures ease of implementation.
Data Source
AI summary
Techniques for animating a non-rigid object in a computer graphics environment. A three-dimensional (3D) curve rigging element representing the non-rigid object is defined, the 3D curve rigging element comprising a plurality of knot primitives. One or more defined values are received for an animation control attribute of a first knot primitive. One or more values are generated, for a second animation control attribute for a second knot primitive, based on the plurality of animation control attributes of a neighboring knot primitive. An animation is then rendered using the 3D curve rigging element. More specifically, one or more defined values for the first attribute of the first knot primitive and the generated value for the second attributes of the second knot primitive are used to generate the animation. The rendered animation is output for display.