Virtual Pen Animation Using Knot Point Interpolation
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Solution Overview
Problem
Current software struggles to animate a virtual pen on a computer screen in a realistic manner, failing to replicate the smooth, variable speed, and thickness of a real pen's movements, especially at sharp angles and when changing direction, which is crucial for creating authentic multimedia presentations.
Innovation Solution
A method that allows users to create and store graphemes and drawings by specifying knot points with attributes such as coordinates, interpolation, pauses, and writing speed, enabling a virtual pen to mimic real pen movements by interpolating these points in real-time for animation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a virtual pen animates writing and drawing on a computer screen, then it can create multimedia presentations, but it fails to replicate the smooth, variable speed, and thickness of a real pen's movements
Solution Approach 1:
The patent segments the writing path into multiple knot points (control points) that define the trajectory. Each knot point can be independently adjusted to control the pen's movement characteristics, allowing precise replication of real pen behavior while maintaining ease of animation creation.
Solution Approach 2:
The patent implements dynamic control of the virtual pen by allowing variable writing speed at different segments of the path. The pen can accelerate or decelerate between knot points, and the line thickness can vary dynamically, mimicking the behavior of a real pen that changes speed and pressure throughout writing movements.
2Productivity
If the virtual pen changes direction sharply at angles, then it can draw geometric shapes, but it draws rounded angles instead of right angles
Solution Approach 1:
The patent applies preliminary action by introducing pause durations at knot points where sharp angles are required. Before the pen changes direction at a knot point, the system pauses for a specified duration, allowing the pen to come to a complete stop and then resume movement in a new direction. This prevents rounded angles caused by continuous motion and enables precise geometric shapes.
3Ease of operation
If the virtual pen moves between graphemes without lifting, then it creates joined-up writing, but it requires complex trajectory calculation
Solution Approach 1:
The patent segments the writing process into discrete graphemes, each defined by its own set of knot points. The system automatically calculates trajectories for transitions between graphemes, handling lifted and joined-up writing modes without requiring manual intervention. This maintains ease of operation while managing complexity through automated trajectory generation.
Data Source
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AI summary
A method to animate on a computer screen a virtual pen which writes and draws on a virtual blackboard in order to simulate a real pen writing on a real blackboard. Graphemes and drawings (50) are created by specifying a subset of knot points (106, 107, 108, 109) from the set of points forming the lines (50) to draw. All the attributes concerning the knot points, as coordinates (201), pauses, speed, thickness, etc., are stored in a file. Subsequently the user types on the keyboard the word to write or selects from a list the drawing to draw. At this point all the attributes of the knot points of the graphemes to write or of the drawing to draw are retrieved from the file and interpolated, and the data obtained are used to animate a virtual pen in such a way it writes and draws looking like a real pen, pausing at the sharp angles, detaching from and landing on the writing surface of the virtual blackboard, varying the thickness and the speed of drawing, using block letters or joined-up writing.