Similarity Comparison of Mechanical Parts

Abstract

It is very often necessary to search for similar parts during designing a new product because modifying existing similar parts is a commonly used way of creating new parts with ease. In this way, the design time and cost can be reduced. Thus it would be nice to have an efficient similarity comparison algorithm that can be used anytime in the design process. In this research, the solid parts are represented by B-rep and similarity comparison is performed in two steps from overall appearances to detail features. First, geometric information is used in low level of detail for easy and fast pre-classification by overall appearances. Then feature information is used to compare the detail shape in high level of detail to find more similar design. To realize the idea above, a multi resolution algorithm is proposed so that a given solid is described by a low resolution appearance and detail features in high resolution. Using this multiresolution representation, parts can be compared based on the overall appearance first to reduce the number of parts to be compared in high resolution, and then detail features are evaluated to retrieve the most similar part. In this way, computational time can be saved by fast classification in the first step and reliability can be preserved by detail comparison in the second step. © 2005 by CAD Solutions Company Limited.