Directable Cloth Animation via Gesture-Based Force Control
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Solution Overview
Problem
In computer-generated imagery and animation, simulating the movement of complex objects like clothing and hair is challenging due to the need for accurate modeling of physical properties and external forces, which can be time-consuming and require advanced knowledge of physics and particle systems, while also being constrained by budget and time limitations.
Innovation Solution
A system that allows users to directly input forces to influence the movement of movable objects, such as clothing or hair, during an animation sequence by drawing arrows or silhouette strokes, enabling the specification of forces that can be applied to vertices of the object, with options to animate these inputs over time and interpolate their parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physically-based numerical methods are used to simulate cloth movement, then realism of animation is improved, but complexity of operation and time consumption increase
Solution Approach 1:
The patent introduces an intermediary system between the animator and the physics simulation engine. This system translates simple user inputs (drag gestures, force directions) into complex physics parameters automatically, allowing animators to control cloth behavior without directly manipulating physical properties or particle systems.
Solution Approach 2:
The patent replaces traditional mechanical interaction with physics engines (direct manipulation of mass, stiffness, damping parameters) with a gesture-based control system. Users interact through intuitive visual gestures that are automatically converted into appropriate physical forces, eliminating the need for animators to understand complex physics parameters.
2Reliability
If accurate physics modeling is used for simulated objects, then animation quality is improved, but time consumption and computational resources increase
Solution Approach 1:
The system performs preliminary analysis of the animation scene and pre-calculates optimal physics parameters and force applications based on the character's motion and cloth properties. This preparation work is done before the actual simulation, reducing the computational burden during rendering and speeding up the overall process.
Solution Approach 2:
The patent applies physics simulation selectively - using full accuracy only where needed (e.g., areas of the cloth that are visible or interact with other objects) and simplified models elsewhere. This partial application of physics modeling maintains visual quality while reducing overall computational requirements and time consumption.
3Measurement precision
If complex physics parameters are used to control simulated objects, then simulation accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent introduces an intermediary system between the animator and the physics simulation engine. This system translates simple user inputs (drag gestures, force directions) into complex physics parameters automatically, allowing animators to control cloth behavior without directly manipulating physical properties or particle systems.
Solution Approach 2:
The system automatically determines appropriate physics parameters and force applications based on the user's simple gestures and the scene context. The physics engine self-adjusts parameters like mass distribution, stiffness, and damping ratios without requiring explicit user specification, making the tool self-sufficient and easier to operate.
4Reliability
If detailed simulation of cloth interactions is performed, then realism is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent extracts and isolates the most critical physics interactions that contribute to visual realism, while omitting or simplifying less important computations. For example, it focuses on gravity and collision forces that are visually significant, while using simplified models for less critical interactions, thereby reducing overall system complexity.
Solution Approach 2:
The system applies different levels of simulation detail to different regions of the cloth based on their visual importance. Areas that are visible or interact with other objects receive detailed physics treatment, while hidden or less important areas use simplified models, optimizing the balance between realism and computational complexity.
Data Source
AI summary
One aspect of the present disclosure is directed to enabling a user to specify one or more forces to influence how a movable object carried by a 3D character may move during an animation sequence of the 3D character. In some embodiments, the user input can include an arrow. The user can be enabled manipulate the arrow to specify values for at least one parameter of the force to be applied to the movable object during the animation sequence. Another aspect of the disclosure is directed to enabling the user to draw a silhouette stroke to direct an animation of the movable object during the animation sequence. The silhouette stroke drawn by the user can be used as a “boundary” towards which the movable object may be “pulled” during the animation sequence. This may involve generating forces according to the position where the silhouette stroke is drawn.