Pro/ENGINEER Gets Its Game On
-by John Fatteross

Whether you're using your Xbox 360 to fight zombies in a virtual shopping mall or annihilate your enemy with magic, you'll be doing it thanks to Cerny Product Development, the small product development firm that had a big hand in developing the controller for the Microsoft product.

It started when the company's president, Greg Cerny, received a call from San Francisco-based Astro Studios - under contract with Microsoft to design the Xbox 360. Astro Studios was facing a big challenge - surfacing the multi-contoured controller required sophisticated desktop software.

The Astro Studios team realized that their 3D surface modeling application wasn't up to the complex challenge.

"Astro Studios had come up with a fantastic design concept. Its design team was extremely talented and detail oriented," says Cerny. "I knew that Pro/ENGINEER could handle the exacting requirements and successfully complete this controller project.

When can you be here? "It was an abrupt start," recalls Cerny. "Astro Studios needed us the next day. The team gave us its 3D CAD files and sketches and we worked with the design and engineering group to make the controller manufacturable, while, at the same time, retaining the ergonomics of a previously designed prototype."

The deliverables were all the outer plastic parts - including buttons, battery and cable strain relief. The parts had to be shelled to the correct wall thickness and modeled with engineering intent, including proper draft angles and clearances. The assembly had to be easily modifiable in case any engineering snags were encountered down the road.

Changes.and more changes. Microsoft is known for its perfectionism - and for multiple rounds of design revisions that must be turned around quickly in order to maintain the production schedule - another reason Cerny was brought on to develop the design files in Pro/ENGINEER.

"The designers at Astro Studios told me that the client's changes were becoming too time-consuming using their current software," says Cerny. "I knew that making multiple changes in short amounts of time is one of the things that really makes Pro/ENGINEER shine."

The wow factor. Cerny knew the Astro Studios designers were frustrated with their modeling software, but dubious about working with the "Pro/ENGINEER guy," and he wanted to impress the team immediately with the capabilities of Pro/ENGINEER.

"The first wall I wanted to knock down was their worry," Cerny says. "I decided I'd wow them on the first day by completing the basic form of this very swoopy and complex product in Pro/ENGINEER."

Cerny developed all the files from Astro Studios in Pro/ENGINEER. "We were given IGES files of a complete controller to start the project. But the files had not yet been fully refined and a handful of engineering realities were yet to be resolved. We were also given a complete internal assembly with the PCB and all internal parts in native Pro/ENGINEER."

After eight hours of hardcore uninterrupted surfacing, Cerny had recreated all the imported surfaces in his master Pro/ENGINEER model.

"It only took one day's work to recreate it, and we knew it would be well worth it if, a week later, the client changed the pull direction of the tooling. And wouldn't you know; that's exactly what happened."

Sweeps for swoops. What Cerny calls a "swoopy" product - one with multiple intersecting curved surfaces - required the variable section sweeps of Pro/ENGINEER to control the surfaces, and the boundary blend tool to make curvature continuous blends.

"The variable section sweep feature is very robust, versatile, and reliable. It is able to handle extreme geometric changes while very rarely causing other features to fail." he says.

Sophisticated analysis tools also played a big part in the design success. The sections analysis tool in Pro/ENGINEER, for example, let Cerny put several evenly spaced cross-sections through his ergonomic model and the model he was creating, so he could easily see variations. And the Pro/ENGINEER curvature analysis tool enabled him to visualize the direction the surface was curving so he could determine where it flattened out, and model his solution accordingly.

Getting the ergonomics right. A key to the project's success was ergonomics. While Microsoft wanted a new controller design for the Xbox 360, they also wanted to maintain the ergonomics of a previously designed prototype. "We were told to keep the geometry within 0.5 mm of the original controller," he says. To do that, Cerny used trajectory parameter or "trajpar."

"The trajectory parameter is determined by Pro/ENGINEER and then fed into a graph to determine a dimensional value," says Cerny. "Used in conjunction with the variable section sweeps, trajpar let me easily and accurately control the surfaces, allowing me to control the intersections of surfaces without compromising the continuity or "flow" of the highlights on the surface."

Cerny varied his graph to experiment with multiple sweep scenarios. "I was able to repeatedly and sometimes drastically modify the geometry without losing any references," he says. "And the model regenerated automatically."

As Pro/ENGINEER made quick work of an otherwise complex design project. The Xbox 360 controller was a huge success and with the controller garnering critical acclaim, so has Cerny Product Development. Astro Studios is now Cerny's biggest fan, and his biggest client.