Duplicate designs consume a significant amount of resources in most new product development. Search of similar parts for a given query part is the key to avoid this problem by facilitating design reuse. Most search algorithms convert the CAD model into a shape signature and compute the similarity between two models according to a measure function of their signatures. However, each algorithm defines the shape signature in a different way, and thus has its own limitations in discriminating 3D parts. This paper proposes a search scheme that successfully complements various shape signatures in similarity assessment of 3D mechanical components. It considers form-feature, topological, and geometric information in component comparison. Such an integrated approach can effectively solve the feature intersection problem, inherited in any feature-based approaches, and capture the user's intent more precisely in the search, which geometry-based methods fail to accomplish. We also develop a set of algorithms that performs the component comparison in a polynomial time. The proposed scheme is implemented in a product design environment consisting of commercial CAD and PDM systems. The result demonstrates the practicality of this work in automatic search of similar mechanical components for design reuse.