Shape Searching Becomes A Reality

By Roland Piquepaille

Tired to type keywords in a general search engine to retrieve an image? A solution is in view. A specialized search engine developed by engineers at Purdue University allows users to draw a sketch of a part or to select one from a database. The system then returns parts having similar shapes. They call it shape searching. They think that companies having huge databases containing existing parts, such as in the automotive or the airline industries, will be able to save millions of dollars annually by saving up to 80 percent of the time necessary to search information on parts.

Engineers at Purdue University are developing a system that will enable people to search huge industry databases by sketching a part from memory, penciling in modifications to an existing part or selecting a part that has a similar shape.

"It's like a special kind of Google that lets you search for parts based on their three-dimensional shapes," said Karthik Ramani, a professor of mechanical engineering and director of the Purdue Research and Education Center for Information Systems in Engineering.

Below is an illustration of the searching process (Credit: Purdue Research and Education Center for Information Systems in Engineering, School of Mechanical Engineering). In a first step, the user selects a catalogued part (left). In the second step, the user can look at parts with similar shapes (right).

You can find larger screenshots with many more shapes demonstrating how the system work, both for a selection and its results.

Here is how they designed the system.

"We take a 3-D model of a part and convert it into a bunch of small cubes called voxels, which stands for volume elements," Ramani said.

The system uses complex software algorithms to convert the voxels into a simplified "skeletal graph" based on "feature vectors," or numbers that represent a part's shape.

But how can a company save money by using such a tool?

"Corporate memory is short," Ramani said. "People leave, managers come and go. They forget file names and project names. This type of system allows you to retrieve your own company's knowledge, your own company's history.

"Let's say there are 1.3 million parts in your inventory. If you are trying to design a part and you can find something similar that was produced in the past that has a lot of value."

Design engineers spend about six weeks per year looking for information on parts, he said.

"The shape-search system will allow engineers to cut this time down by as much as 80 percent," Ramani said.

Even if the system gives results with an accuracy of up to 85 percent, it is not ready yet for commercialization. However, a patent has been filed and already one company agreed to license the technology.

You can find more information about this system in an article from CNET News.com, "Search prototype gets the picture."

Source: Karthik Ramani (source) and Emil Venere (writer), Purdue University news release, March 30, 2004