In Part 1, Useful Search Applications for Finding Engineering Data, I identified text-oriented solutions. Another approach is to search CAD models by shape and both shape and text.
Now, I’ll introduce and comment on shape-based search methods and values, identify some vendors and their offerings and suggest further actions.
Courtesy of Actify, Inc.
Even if you are reading about shape-based search for the first time, let me assure you that geometric search is far from being a bleeding edge technology with all its attendant risks. Components for geometric methods, such as feature recognition, have been around for decades. Using proven technology, several software vendors have developed shape-based searching tools as early as the mid-2000s — often with the support of university research projects.
What’s Different About Geometric (Shape-Based) Searching?
Let’s start with a simple definition: Geometric search, or shape-based search, uses a mathematical abstraction of a part to seek and find parts with identical or similar shapes. Shape-based searching is different from text-oriented methods that rely on keyword inquiries and accurate metadata.
Effective shape-based searching depends on shape signatures for discovering and finding needed product data. A signature is a less complex version of the 3D model. Individual signatures are created and maintained in a signature file, a small file, to optimize searching for the native CAD models or neutral file formats. Most of the identified tools span both choices.
Prior to active searching, an indexing process creates the signatures. Numerous methods exist to do so, each with respective strengths and weaknesses that affect accuracy and use. The capabilities will vary for each vendor’s tool. Here are a few to look for:
- Encrypting to protect intellectual property rights of the company
- Handling of file formats
- Negating need for a pre-defined classification scheme.
Similarity: Searching, Discovering, Finding
With the input of a sketch or skeletal design, the signature file initiates the initial search. Similarity displays are presented to help users narrow the choices to find specific matches to their needs. These displays may be general (see Figure 1) or in detail (see Figure 2). They show a ranking of similarity by visual and textual information, according to the vendor’s algorithm — often a “secret sauce.” The Siemens display indicates similarity by the green bar supplemented by textual information. While display styles may differ, the purpose is the same — help the user on their way to the most similar part.
Additional discovering may be necessary, facilitated by secondary displays.
Discovering a whole bunch of choices is a start, but not enough. What if the discovery step shows identical choices based on shape, but the materials may be different? Thus, finding a specific match may require analyzing text attributes found in PLM/PDM systems. For a complete set of searching capabilities, text searching is necessary; methods vary as described in Where Search & Discover Solutions Fit in Product Development.
What’s the Value of Geometric Methods?
Design reuse is the benefit most often cited by geometric search vendors. In common with text search, geometric search also eliminates duplication, improves engineering productivity and more. Cost improvement is arguably the easiest to attain; surveys tell us that the cost could range from $6,000 to over $20,000 per avoided part assignment. If the costs have already been incurred, and inventory has resulted, part cost reductions are another matter.
When presenting their shape-based products, most tool vendors will stress the superiority of geometric searching over text-oriented solutions. Valid to a point, however, the weakness of a text-oriented solution may not be the tool itself, but the lack of valid metadata in a company’s product data infrastructure hindering specific finding of design needs.
Another value is to unify and compress design activities in the supply chain that have to cope with increasing pressures, such as time-to-market and environmental regulations. A strategic initiative is based on collaborative component and supplier management (CSM) capabilities, defined as:
- Component — to support selection, design reuse, access to 3D digital component catalogs and new part introduction processes that negate assigning duplicate part numbers.
- Supplier — to support vendor selection and evaluation, enhance collaborative product development, drive part and supplier rationalization and reduce the risks in the supply chain.
As a preface to the next section, I stress that my identification of the vendors is representative, rather than comprehensive. I’m not attempting to identify all sources, but would rather show you some of the representative solutions available.
Who Are Vendors and What Do They Offer?
Vendors range from the largest, e.g., EXALEAD and Siemens PLM Software, to boutique firms focused solely on search tools. Two products, Enfinio and Similarity by Dassault Systèmes, were not available for review. Other than those two, following is as complete a wrap-up as possible of the major products in shape search.