Abstract

In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features). The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.

Highlights

  • In curved surface designs, the overall shape features that emerge due to combinations of shape elements are important because humans tend to perceive the overall shape features macroscopically [1,2,3,4,5]

  • The objective of this study is to propose macroscopic shape information to represent the overall shape features in curved profiles and to confirm its effectiveness

  • According to our previous study [24], six evaluation items are important to represent the macroscopic features in a curved profile

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Summary

Introduction

The overall shape features that emerge due to combinations of shape elements are important because humans tend to perceive the overall shape features macroscopically [1,2,3,4,5]. The objective of this study is to propose macroscopic shape information to represent the overall shape features in curved profiles and to confirm its effectiveness. In previous research on the texture and pattern of the cell structure [14,15], entropy in information theory has been used as an index to represent macroscopic features. To examine the availability of the method and index, this method is applied to the side view design of an automobile, which is expressed by a three-dimensional Bézier curve, and a cognition experiment using the generated shapes is conducted to confirm if the entropy adequately represents the cognition information

Definition of Macroscopic Shape Information
Angle Variation
Curvature Variation
Description of Basic Curved Profiles
10. Average radius vector
Cognition Experiment of the Curved Profile
Relationship between Microscopic and Macroscopic Shape Information
Relationship between the Tangent Vector and Shape Information
Relationship between Shape Information and Cognition Information
Improvement of the Macroscopic Shape Information
Definition of the Quadratic Curvature Entropy
Description of the Initial Shape
Coding in a Genetic Algorithm
Description of the Initial Shapeand Conditions in the Genetic Algorithm
Shape Generation and Cognition Experiment
Relationship between Macroscopic Shape Information and Cognition Information
Conclusions
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