Shape similarity assessment is a fundamental geometric reasoning problem that finds application in several different product design and manufacturing applications. A computationally efficient way to assess shape similarity is to first abstract 3D object shapes into shape signatures and use shape signatures to perform similarity assessment. Several different types of shape signatures have been developed in the past. This paper provides a survey of existing algorithms for computing and comparing shape signatures. Our survey consists of a description of the desired properties of shape signatures, a scheme for classifying different types of shape signatures, and descriptions of representative algorithms for computing and comparing shape signatures. This survey concludes by identifying directions for future research.

This paper presents algorithms for identifying machined parts in a database that are similar to a given query part based on machining features. In this paper we only consider parts that are machined on 3-axis machining centers. We utilize reduced feature vectors consisting of machining feature access directions, feature types, feature volumes, feature dimensional tolerances and feature group cardinality as a basis for assessing shape similarity. We have defined a distance function between two sets of reduced feature vectors to assess the similarity between them from the machining effort point of view. To assess similarity between the two parts, one set of reduced feature vectors is transformed in space using rigid body transformations with respect to the other set such that the distance between them is minimized. The distance between the two sets of aligned reduced feature vectors is used as a measure of similarity between the two parts. The existing machined parts are rank ordered based on the value of the distance with respect to the query part. The cost of previously machined parts that have a very small distance from the query part can be used as a basis for estimating the cost of machining the new part.

This paper presents a method for identifying those parts in a database that are similar to a given query part to be machined and hence can be potentially used as a basis for estimating the machining cost of the query part. We utilize projected feature vectors consisting of feature access directions, feature types, and feature volumes as a basis for assessing shape similarity. We have defined a distance function between two sets of projected feature vectors to assess the similarity between them from the cost estimation point of view. To assess similarity between the two parts, one set of projected feature vectors is transformed in space using rigid body transformations with respect to the other set such that the distance between them is minimized. The distance between the projected feature vectors is used as a measure of similarity between the two parts. The existing parts are rank ordered based on the value of the distance with respect to the new part. The cost of machining the new part can then be estimated by using the cost of previously machined parts that have a very small distance from the new part.

This paper describes a system and underlying algorithms to perform geometric containment analysis to determine if a newly designed rotational part can be manufactured from a part in an existing database of rotational parts. Only material removal of the database part is considered in order to obtain the newly designed part from the database part. The system uses a three-step algorithm to test for containment. The first step analyzes feasibility of containment using bounding cylinders. If the bounding cylinder of the query part is bigger than the part in the database, then the database part cannot contain the query part and it is eliminated from consideration. The second step analyzes feasibility of containment by ignoring off-axis features. Any part that fails to satisfy containment at this stage is eliminated from consideration. The third step analyzes the remaining parts from the database for feasibility of containment by including the off-axis features. Finally, the system rank-orders all the database parts that can contain the query part based on their volume differences with the query part. The system described in this paper can be used by designers and process planners to find an existing part that can be used as a stock to manufacture a newly designed part. This capability is expected to significantly reduce proliferation of parts, to improve manufacturing responsiveness, and to reduce the cost of new products.

Manufacturing companies often need to reuse existing design information to reduce cost and timeto-market. This requires search tools that are capable of locating previously designed parts. Many geometry-based search techniques have been developed to locate parts similar to the input query part. But these techniques are not effective if the user does not have a query part to provide as input to the geometry-based search system. This paper describes an integrated search system for searching a part database both visually and geometrically for locating and retrieving parts. The visual and geometry-based search tools of this integrated system are highly interconnected and provide a seamless transition between either modes of searching. The visual search tool uses levelof-detail techniques to display a large number of parts in the scene. It has multiple navigation and sorting utilities to search the database visually. The geometry-based search tool uses gross-shape based search techniques to provide effective searching capabilities. The system described in this paper has been tested with a wide variety of parts.