Issue link: https://digital.copcomm.com/i/83694
Simulation n n n n Santos and Sophia are part of a new outsourcing trend. This time, the jobs are not shifting from high-salaried, skilled workers in the First World to low-cost laborers over- seas. Instead, they're shifting from human workers to digital workers. But you may take comfort in the fact that the types of operations ceded to digital humans are the works many of us would consider too dangerous, stressful, or painful to perform to begin with. (Sometimes, they're literally back- breaking jobs.) When the Army needs to figure out how a 10-pound vest would affect a sniper's agility and fatigue level, when an automaker needs someone to crawl into a tight space previously untested, when a plant manager needs someone to perform a series of ergonomically risky maneu- vers, they may now turn to digital human models (DHMs). Working with CAD Geometry DHM-incorporated simulation exercises often involve 3D CAD files because the human-machine interaction usually takes place in a virtual environment, detailed and populated with standard CAD objects (3D models of armored vehi- cles, mechanical assemblies, and plant layouts, for example). Studying product designs (how a driver might navigate inside a smaller-than-average electric car) and manufactur- ing operations (how a repair technician might install an exhaust pipe) invariably require a mix of files created in different CAD programs. Therefore, for DHM-incorporated simulations, a solution that can ac- commodate—in other words, import—not just the software maker's proprietary format, but also many different CAD formats, is preferable. Many design, engineering, and simulation software makers have been developing and perfecting their own technologies to cater to this relatively new field. Siemens PLM Software's digital humans, called Jack and Jill, are part of the company's Tecnomatix digital manufac- turing software suite and integrated with the company's NX CAD package. A basic version of PTC's digital manikin is included in the company's flagship product, Creo Parametric (formerly Pro/Engi- neer). Another version with greater functionalities, dubbed PTC Creo Manikin Extension, can be purchased from Dassault Systemes' Virtual Ergonomics Solutions suite, which includes male and female digital manikins called Teo and Sia, and are integrated with the company's CATIA (CAD), DELMIA (computer-aided manufacturing), and ENOVIA (product lifecycle management) software packages. San- tosHuman partners with Okino Computer Graphics, a CAD trans- lation technology developer, to make its DHM software compatible with industry-standard 3D file formats. Human Constraints Unlike the type of semi-autonomous extras and player-controlled char- acters commonly found in video and computer games, digital humans used in simulation are designed with significant motion restrictions. In virtual environments like Second Life and World of Warcraft, an av- atar could be a 9-foot-tall, blue-skinned elf archer with superhuman strength. After a few quests, he may even be permitted to wield a club twice the size of his body mass or fly through the clouds. After all, doing what's not physically possible in real life is one of the main attractions of the virtual world. In simulation applications, it's important to prevent digital humans from performing moves and maneuvers that are outside of what is pos- sible within the human population. The restriction is deliberate. It's meant to give users—army engineers, facility managers, plant designers, Some manufacturers use digital human models to identify and correct ergonomic issues in tight-fitting vehicles, like the cockpit of a plane. The simulation shows Siemens PLM Software's Jack and Jill. Julie Charland, product manager of Virtual Ergonomics at Dassault Systemes. "In our applications, the manikin has to be no bigger than [typical] humans, with accurate anatomy and kinematics controlling their movements. If you pull on our manikin's arm, for example, it will only stretch as far as a human arm will—it can't go farther. Game ava- tars don't need to know where their center of gravity is. Our manikins need to know that." "The difference between 3D characters in games and DHMs in engi- neering software is the difference between making something look good and making something right," notes PTC's Buchowski. "When you're dealing with human behavior simulation in product design, there's actually a library of typical body types you need to use as reference: for instance, 50 percentile North American male or 30 percentile Asian female. I challenge you to find a woman who matches Lara Croft's pro- portions in real life." and ergonomists, among others—confidence that the digital humans' reaches, crouches, and bends accurately represent an average soldier's or employee's range of motion, along with his or her limitations. "The breadth of things our digital humans [Jack and Jill] can do cov- er the breadth of things real humans can do," explains Tom Hoffman, director of Tecnomatix Global Marketing for Siemens PLM Software. John Buchowski, vice president of product management at PTC, notes, "The degrees of freedom available to our manikin are the same ones available to real humans." "In the movie Avatar, the Na'vi characters are 10 feet tall," notes The Science of Agony DHM simulations produce more than visual references for movements, reaches, and lines of sight. They're designed to collect other data, such as the amount of force applied to joints (often called joint torque), joint strength capabilities, internal muscle forces, and intervertebral disc compressive force. This allows army engineers, product designers, and ergonomists to address questions such as, How long can a pilot remain in a small cockpit without feeling stress on his or her back? How long can an average person continuously lift and drop a 50-pound part in an assembly line? How far would a repair technician need to bend to August/September 2012 25 Image courtesy Siemens PLM Software.