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Best Seat in the House

T-Splines for Rhino finally gives industrial designers access to fast polygonal modeling

By Brett Duesing, Strategic Reach

The Grand Theatre stands as the centerpiece of the UK arts district in Blackpool, the beachside resort town that has entertained generations of Brits on holiday. The 1,100-seat Victorian auditorium functions as the town's community theatre, Lancashire's preferred opera house and Britain's National Theatre of Variety.

Restoring the 1894 structure to its former glory involved some unusual challenges - one of which was replacing the seats. JEZET-Seating was contracted to the task, but could not find auditorium seats in the commercial market that matched the Grand Theatre's distinctive turn-of-the-century opulence.

The solution for the thousand-chair order involved the commission of a Belgian furniture craftsman Peter Donders, who was not only familiar with traditional methods of chair-making, but was also savvy in the computerized art of 3D industrial design. To make new chairs look convincingly antique, Donders uses a 3D method for product development, T-Splines, a technological design advance that is itself history in the making.

The Chairman

"After much research and development, we produced a new seat based on a design by A. R. Dean of Birmingham, circa 1913," explains Donders. "I came in around September 2006 for the 3D design and produced the chairs in about nine months. The seats have cast stantions with beech-frame backs and swabs."

Donders started his career making single custom chairs by hand. Now through use of 3D production methods, he designs seats that fill whole theatres and stadiums. For the Grand, Donders composed the chair design in Rhinoceros, a 3D CAD modeler valued by a broad range of industrial designers, both for its easy ability to generate curved lines, and its capability of describing these surfaces with pinpoint accuracy, as mathematic equations called non-uniform rational b-splines, or NURBS.

Unlike 3D modelers used solely for virtual content like animation or film effects, Rhinoceros' outputs are attached to precise real-world measurements. The 3D data guides automated machines like laser cutters, CNC mills, and 3D printers to quickly manufacture new products.

"I had some 15 years experience as a furniture designer and builder before I ever even considered using computers," says Donders. "Nowadays, using the computer is pretty much like using any other tool that facilitates the design and development process."

Going Organic: The ornate cast-iron stantion underneath the arm would have been very time-consuming to create in Rhinoceros alone, requiring many individual surfaces to be patched together to describe all the details. For this part, Donders employed a polygonal or subdivisional surface modeling technology, which is ordinarily used for animations. The model starts out as a enclosed volume that can be twisted and extruded quickly to create the desired forms, rather than assembling a tedious patchwork of exterior wireframes.

The T-Splines Plug-In for Rhino

A tool that Donders discovered "just in time" for his Grand Theatre project was the beta version of T-Splines plug-in for Rhino. The program operates inside the surface modeler, and gives Donders and other industrial designers a tremendous enhancement in modeling flexibility.

"Rhino is well known as an excellent free-form surfacing package. What T-Splines brings to Rhino is the ability to have even more organic shapes," says Matt Sederberg, CEO of T-Splines, Inc., which developed the plug-in. T-Splines leverages both NURBS, and what's called polygonal or subdivisional surfaces, to generate shapes. Polygonal modeling is common in modelers for advanced animation, but until now has not been accessible to those who build products.

"Pixar uses polygonal and subdivision surfaces modeling technology to create 3D animated characters," Sederberg explains. "A lot of industrial designers have started to look towards this type of modeling because it's much easier to get a nice complex surface with smooth transitions between features."

Rhino produces NURBS that start out as rectangular planes, which then can be bent and tweaked to form the curve the designer wants. To make an irregular form that is a self-contained volume, designers typically have to panelize the form with a patchwork of NURBS. With T-Splines, on the other hand, designers can use polygonal or subdivisional modeling techniques, beginning with a 3D volume that can be stretched, extruded, and twisted, while maintaining the volume's continuity.

"With T-Splines, we can make a non-rectangular shape that is one surface and smooth everywhere," says Sederberg. "If we made this shape in Rhino without T-Splines, we would have to spend a lot of time making sure the edges of composite surfaces patch together correctly without gaps or misalignment. 'You don't have to deal with patches.' -- that's just a few words, but that's essentially what T-Splines mean to Rhino users. It's a huge time-saver." Depending on the project, the additions of polygonal capabilities reduce modeling time by 20 to 30 percent.

There are a host of polygonal based modelers already on the market, according to Sederberg, including brands like 3D Max, Hexagon, modo, and Silo. The limitation to these applications has been that they produced pretty pictures - animation, film effects, or video-game scenes - but could not be linked to NURBS, which product designers use to communicate geometry to factory machines. Through T-Splines in Rhino, these two separate modeling methods are finally linked in tandem. Polygon-produced shapes can now be produced as real-world objects.

"T-Splines is the first program to actually do that polygonal modeling in a way that's compatible with NURBS," he says. "With T-Splines, you can easily get very complex geometries, and in the end be able to manufacture it."

Stantion Production

Donders' chairs give an excellent example of how polygons and NURBS can now come together in a design process.

"A lot of the parts of the chair are surfaces that Rhino can model very well all by itself," says Sedenberg. But one highly detailed part --the ornately curled stantion under the arm of the chair -- makes it a prime candidate for polygonal manipulation.

"I don't think you would even dream of modeling something like that in Rhino. It's something that's easy to model in the T-Splines plug-in, but for someone who's already familiar with polygonal modeling, it's also easy for them to model the entire shape in a polygonal modeling application."

Donders modeled the stantion in a popular polygonal modeling program called Hexagon, and then brought it into T-Splines in Rhino, where he seamlessly converted the shape to NURBS. "It's just a push-button operation to convert the data. Without additional work or editing, the designer has an extremely complicated ironwork design ready for fabrication," says Sedenburg.

The T-Splines plug-in for Rhino version 1.0 was released in September 2007, and is now available through the company's website, or through various Rhinoceros resellers. The module contains a suite of polygonal modeling and surface building tools, along with the flexible data translation capabilities for models from other applications.

"The Blackpool project focuses on one aspect of the T-Splines plug-in - the ability to convert low-polygon-count meshes to T-Splines inside Rhino, so that the form can be manufactured," Sedenburg says.

As another user of T-Splines, designer Jonah Barnett puts it, "Designers will no longer have to choose between incompatible modeling technologies. They are free to use whichever method delivers the best results in the shortest amount of time. And T-Splines is the bridge which finally makes it possible. T-Splines is an indispensable tool, whether you are modeling for animation or for manufacturing."

As for the Grand Theatre, the audiences are now seated in style after the completed restoration. Donders may have stumbled upon something big with his revival design. "The architect who built the Grand in 1894, Frank Matcham, built almost 30 other public auditoriums and music halls throughout the UK," says Donders. The popular appeal of Matcham's theatres has spawned a national society to preserve his work. Donders has just received orders for hundreds more chairs -- to fill rows in the Royal Hall in Harrogate, as well as another location on the west end of London.


About Peter Donders

To view other projects by the Belgium-based craftsman, furniture designer, and 3D modeling expert Peter Donders, please visit: www.peterdonders.com.

About T-Splines, Inc.

T-Splines, Inc. develops surface modeling software with optimal control and full industry standard compatibility for industrial designers and CAD professionals. Founded in 2004 and based in Provo, UT, the company develops and markets end-user plug-ins and software development libraries based on its next-generation NURBS-compatible technology. For information on the T-Splines plug-in for Rhinoceros, please visit: www.tsplines.com.

About Rhinoceros

Rhinoceros provides the tools to accurately model your designs ready for rendering, animation, drafting, engineering, analysis, and manufacturing. Rhino can create, edit, analyze, and translate NURBS curves, surfaces, and solids in Windows, without limits on complexity, degree, or size. Rhino gives the accuracy needed to design, prototype, engineer, analyze, and manufacture anything from an airplane to jewelry. Rhino provides the compatibility, accessibility, and speed in an uninhibited free-form modeler that are found only in products costing 20 to 50 times the price. To see the many diverse products designed with this affordable 3 D tool, and to download a free evaluation version, please visit: www.rhino3D.com.

Press Articles...

AEC Magazine (click to read)

Addendum:some projects realised after Blackpool

(click the images to view the corresponding public facebook album)

Seats... Gothenburg

Seats... Stockholm

Seats... Singapore 5000

Seats... Birmingham

Seats... Brussels

Seats... London

There's even more on https://www.facebook.com/morphs.be/photos_albums


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