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September 1, 2001

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Touch-sensitive modeling in digital clay


The FreeForm modeling system provides designers with an analog interface to create a digital model. The Phantom haptics interface, or stylus, provides designers with a touch-sensitive means to sculpt, carve, push, and tug on digital clay.

If, like many sci-fi fans, you were disappointed by the movie A.I., this article will lift your spirits. There is fascinating news coming from the field of artificial intelligence, especially as it relates to design. One of the more recent developments to come from SensAble Technologies (founded by researchers at MIT's Artificial Intelligence Laboratory) is the FreeForm modeling system. It consists of both CAD software and a haptics interface, which, in simple terms, is a touch-sensitive stylus. Why is this good news? Because it finally solves the dilemma that many industrial designers and stylists encounter when trying to "sculpt" a design using 3-D CAD. Namely, it adds the sensation of touch, or more accurately, force and pressure feedback. 

Analog to Digital 
According to Bruce Boes, vp of business strategy for SensAble, the system is a digital answer for an analog process. "Typically, designers produce a clay or foam model, then someone else puts it into a digital system as a surface model. All of a sudden, what the designer intended is lost," he adds. "Even reverse engineering a model with a scanner loses some design intent." 

Instead, a designer using the FreeForm system and Phantom interface sees a block of clay on screen, and proceeds to sculpt it with the stylus, all the while feeling as though he or she is really pushing it into the virtual clay. "It's not actually a tactile system, but rather a pressure and force feedback," says Boes, "and it's very difficult to imagine it without having tried it." 

Now in version 4 of its FreeForm software, SensAble has introduced additional modeling techniques for shaping, deforming, and creating 3-D curves to drive shapes to predesigned constraints. "In many markets, you need a hole here, or a contour along this curve. Now those curves can be imported and we can use our techniques along with them," says Boes. "It's the blend of these two things—the ability to sculpt and also work with constrained data—that helps designers optimize form with function." 


A composited image of a model painted in FreeForm.

Speeding Time to Market 
Customers such as Adidas, Hasbro, Nokia, and Motorola customarily decline to be interviewed for their feedback. However, a product design and development firm, RJ Studios, commented on this technology. Says Muggs Ferguson, director of new technology, "This system has enabled us to reduce time to market by 20 percent. This is significant, because we are really in the business of saving time for our customers." 

RJ Studios consists of 30 artists, mechanical engineers, and manufacturers. It is noted for its ability to take an animated license property, sculpt it in 3-D, insert an engineered mechanism, and then mass produce it. Among its customers are Mattel and Fisher-Price. RJ is still getting its feet wet with FreeForm and doesn't yet use all of the features offered by the software, but the firm has worked the application into the design process. 

One use is model creation. Under the previous method, it takes one of RJ's sculptors 60 to 80 hours to create a model of a licensed cartoon character in wax. If all goes well, the licensor who commissioned it likes the model and approves it for production. Of course, to accommodate for shrinkage and the other vagaries of the molding process, the production model needs to be slightly larger than the original wax model. 

The sculptor then creates the model again, making sure that each feature, detail, and nuance of the new model is precisely and uniformly larger than the original. The resculpt takes about the same amount of time as the original. Then the licensor has to examine the enlarged sculpt and approve it again. 

With sculpting software, the model is scanned and brought into the FreeForm system. A few keystrokes later, a digital model that is exactly a given percentage larger than the original is created. And because the new model is a digital clone of the original, the licensor doesn't have to approve it again. 

With this system, RJ Studios can now place a model into the downstream workflow in three ways: by scanning a wax model, by creating a model in a CAD package, and by sculpting a model in FreeForm modeling itself. As the artists become more familiar with the system, this last option looks compelling to Ferguson. "I want to have my sculptors use the FreeForm system from scratch, from the very beginning of the design process, in order to fully take advantage of its time-saving capabilities." 

Contact information
SensAble Technologies
Woburn, MA
(781) 937-8315

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