Regular patterns of repeated elements in CAD assembly model retrieval

The extensive use of CAX tools in industry leads to a mushrooming accumulation of CAD models that are stored in databases. While designing new products, designers usually reuse existing models to speed up the design process. However, nowadays, databases are so large that designers struggle to retrieve product data in general - i.e. drawings, simulation models, videos, technical reports - and CAD assembly models in particular. An efficient retrieval of assembly models requires also information that is implicitly encoded in the CAD models. This implicit information must be made explicit to become usable. So far, the most common solutions rely on the use of Product Data Management (PDM) systems. PDM systems ease the organization and management of product data by enabling designers to add textual metadata. Although PDM systems efficiently manage text-based queries, they do not always fulfil designers' needs. Indeed, sometimes designers prefer to query the system for models geometrically or structurally similar to an existing CAD model (single part or assembly). Content-based algorithms enhanced by additional geometric characteristics are an alternative to extend text-based search capabilities to retrieve 3D models.