Bezier Curve Control Point Calculation from User Points

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Solution Overview

Problem

Existing computer graphics systems require users to manually define and manipulate control points for Bezier curves, which can be cumbersome and dissimilar to freehand drawing, limiting creativity and efficiency in curve definition.

Innovation Solution

A system that automatically calculates control points from a series of user-defined points based on relative distances between them, using equations to generate Bezier curves, allowing for intuitive freehand creation and manipulation of curves without explicit control point specification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If users manually define and manipulate control points for Bezier curves, then the curve can be precisely controlled, but the operation becomes cumbersome and complex

Engineering Contradiction:
Improvecurve precisionVSAvoidoperation simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system automatically calculates control points based on the sequence of points defined by the user's freehand drawing, eliminating the need for users to manually specify control points. The algorithm uses the relative positions of consecutive points to compute appropriate control points, allowing the system to serve itself rather than requiring explicit user input for each control point.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the parameters from explicit control point coordinates to relative distance ratios between consecutive points. By using the ratios of distances between successive points in the user-defined sequence, the system transforms the control point calculation into a automatic process that preserves curve precision while simplifying user interaction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If users manually define control points, then mathematical completeness is maintained, but the interface complexity increases

Engineering Contradiction:
Improvemathematical completenessVSAvoidinterface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system introduces an intermediary algorithm that translates simple user drawing actions into mathematically complete Bezier curve definitions. The algorithm acts as a mediator between the simple freehand point sequence and the complex control point requirements, automatically computing the necessary control points while maintaining mathematical completeness without increasing interface complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the click-and-drag approach is used for point identification, then control precision is achieved, but creativity is dampened due to cumbersome operation

Engineering Contradiction:
Improvepoint identification precisionVSAvoidcreative freedom
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The invention replaces the mechanical click-and-drag interaction with an automated calculation system. Instead of requiring users to manually position and identify control points through complex dragging operations, the system automatically computes control points from the sequence of points defined by the user's drawing path, substituting the mechanical interaction with an intelligent calculation that preserves precision while enabling creativity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2244229B1Generation of cubic bezier control points in computer graphics systems
Publication Date: 2013.09.18 SONY INTERACTIVE ENTERTAINMENT LLC
  • EP2244229B1 patent drawingFigure 1A~1B
  • EP2244229B1 patent drawingFigure 1C~1D
  • EP2244229B1 patent drawingFigure 1E~2

AI summary

A system for interactive computer graphics enables generation of Bezier curves from a series of points based on the relative position of successive points in the series. For example, for successive points in a series, point A, point B, and point C are successive points in the series of points, and wherein a control point corresponding to point B and associated with the segment AB is determined by the equation B + RA *( RA *(B-C) + RC *(A-B)), and a control point corresponding to point B and associated with the segment BC is determined by the equation PBBC = B + RC *(RA *(C-B) + RC *(B-A) ), where RA = |AB| / (|AB|+|BC|), and RC = |BC| / (|AB|+|BC|).