Caren D. Potter
When my brothers were growing up they had great fun playing with their "army men." These little olive-green plastic figures, which came in about a half-dozen different shapes, all had the same squinty-eyed grimace. How different it would be if my brothers were growing up today. Assuming they were allowed to have army men at all, they`d probably be playing with action figures of characters from the movie Toy Soldiers. Or perhaps more likely, they`d have reproductions of Qui-Gon Jinn, Obi-Wan Kenobi, and Darth Maul from Star Wars Episode One: The Phantom Menace. In any case, rather than playing with generic, one-face-fits-all characters, they would have toy replicas that looked just like their on-screen counterparts.
|Gentle Giant made rapid prototypes of the toys from digital 3D models and hand-finished them to create molds for mass production. |
Creating toy facsimiles of movie characters is big business in the toy industry today. The figures can be based on live humans, such as Kay and Jay of Men in Black. (In fact, there are Men in Black action figures with faces that are almost identical to those of Tommy Lee Jones and Will Smith.) Or the toys can be based on animated characters such as Buzz and Woody from Toy Story 2 (see "The Toys Are Back," pg. 27).
There are two big challenges to turning movie characters into toys. First, no matter what the toy is, from a huge stuffed object to a bauble on a key ring, it must closely resemble what people have seen on the big screen. Even an item as small as a Buzz Lightyear pencil topper can`t just have a space helmet and the general shape of a spaceman. It must look like Buzz.
"You can`t blame the licensors" [the studios that own rights to the characters], says Robert Curet, vice president for creative development at Playworks, a toy-prototyping sculpture house in Westlake Village, California. "They worked so hard to design those characters, they want to make sure that what is sold is the same as what they created."
The other challenge is that movie toys need to be available when the movie opens or very soon thereafter. This means that toy makers often have less time to make the products than the movie company has had to make the movie. Meeting that deadline is becoming increasingly difficult. "We used to get the go-ahead a year before a movie came out," says Karl Meyer, president of Gentle Giant Studios, a licensed-product builder in Burbank, California. "But, it`s a faster pace now. People are able to make movies more quickly, and, as result, our advance time is getting shorter. Fortunately, because of technology we`ve been able to speed up our process as well."
|To model Buzz, Woody, and other Toy Story 2 toys, Gentle Giant imported animation data into Alias|Wavefront`s Maya to pose the characters as desired. |
Computer technology is not only helping toy makers save time. It also simplifies the process of making toys look like characters in movies. Consider how a movie toy was made in the past. First, a sculptor looked at drawings of the character and began to shape a 3D figure in clay or wax. Sometimes the job was complicated by the fact that the drawings weren`t always consistent. A front view might depict the character with a longer upper torso than the rear view, for example. But sculptors were usually talented enough to overcome such obstacles.
The real drawback came when they took the sculpted figure to the licensor for approval. If it deviated from the look of the movie character by even a hair, they had to fix it. Worse, the licensor or even their own management might approve the look of the sculpture but decide it should be 20% smaller than what was originally asked for. This meant starting over. Once the sculpture was approved, it became the basis for the injection mold from which the toy was mass produced. This part of the process has benefited from the use of CAD and CAM for some time. In fact, it isn`t that different from making any other injection-molded product (see "Toying with CAD" below).
The more recent benefits of using digital technology has come in speeding up the scuplting process. Consider a toy that Playworks recently developed from the Warner Bros. feature film, Iron Giant (see "Ten Ton Toon," pg. 36). Warner Home Video asked Playworks to create a small plastic replica of the giant that will be bundled with the videotape of the movie when it goes on sale. Playworks was given a DXF file of the Iron Giant CAD model, so rather than starting the process with a wax sculpture, it began with the digital representation of the giant.
There was a small glitch, however, that prevented Playworks from working with the studio`s data exactly as received. Because of the stacking requirements for videotapes, the toy that Playworks was asked to produce could be only 3/4-inch thick. "The Iron Giant is a barrel-chested character, so one of the first things we had to do was take the data and compress it so that our figure was just 3/4-inch thick," says Curet. "In doing that, we had to make sure that he still looked like he`s supposed to look."
Playworks imported the DXF file into 3D Studio Max, where an artist adjusted the giant`s shape. "The program makes it easy to alter the scale of an object while keeping some of the original proportions," explains Brian Wilcox, head of the computer department at Playworks. "You can scale along one plane and keep the others intact."
After Playworks made a physical model of the toy on a ThermoJet 3D printer from 3D Systems. The object was then molded in silicone and cast in wax. Next, a sculptor refined the wax figure, and Playworks showed it to the client for approval. "Computer prototypes are a little stiff," explains Curet, "so it`s still an industry standard to mold in wax."
One advantage of using a rapid prototype as the starting point for the wax sculpture is that it pretty much ensures that the design will be approved by the licensor. "We`re using the actual character, not interpreting someone`s else work, so when it comes to approval, it`s correct," says Gentle Giant`s Meyer. Another advantage is that once the digital model is available, it`s easy to adapt to make additional toys in different sizes.
When a computer model of a movie character is available, as it often is these days, creating a digital model and rapid prototype prior to making the traditional wax sculpture is becoming the preferred process. Gentle Giant prototyped many Toy Story 2 toys using this approach. Artists imported digital-animation data into Alias|Wavefront`s Maya, where they posed the characters in the shapes they wanted for the toy. A "Woody" bank might have a different pose from a "Woody" cup topper, for example. Or, a toy might have two characters posed together, such as Woody and his horse, Bullseye.
Once the artists were happy with the posed figures, they converted the Maya models into STL files from which they made rapid prototypes in the desired sizes. Gentle Giant uses both stereolithography and ThermoJet machines from 3D Systems for rapid prototyping.
Sculptors at Playworks imported a CAD file of the Iron Giant into 3D Studio Max (above) and created a flatter toy replica (above right) to fit packaging specifications.
The Toy Story 2 characters were then hand-finished because, Meyer says, "the level of finish from the RP machines is not as smooth as glass, and we want these to look good because they form the basis for the rest of the process."
From the rapid prototypes, Gentle Giant created molds in the in-house mold shop so it could cast the figures in its own working wax. Hand finishing was required here, too, to bring the wax models "to a pristine state that lends itself to better tooling." The last steps, once the wax sculptures were approved, were to cast them in hard urethane resin and meticulously hand-clean them to produce tooling-quality master prototypes. In this way, Gentle Giant was able to create more than 100 Toy Story 2 toy prototypes for its client, Thinkway Toys, in a matter of weeks.
What happens when the character is a live actor, and there`s no digital model of a movie character to start the toy-making process? The lack of a digital file is not a problem for Gentle Giant. The company can create a maquette, a small model that licensors distribute as a style guide, using a Cyberware 3030 high-resolution laser scanner. The point-cloud data that comes from the scanner is surfaced using the company`s proprietary G-Sculpt software. From there, the model goes to Maya to be sized and posed, and the rest of process unfolds as described above.
Among the companies that produce toy prototypes from recognizable characters, there seem to three different philosophies. One, represented by Gentle Giant and Playworks, is to use digital technology publicly, so that it becomes the industry norm. "It`s best to embrace the technology and be associated with the forefront," says Meyer. Another tactic is to use digital tools but keep them secret, in hopes of maintaining a competitive advantage. In fact, that camp is represented by several companies that asked not to be mentioned. The third strategy is to continue to do things the old way. This one reminds me of manufacturing companies that insisted for years that they did not need CAD. I wonder what they`re doing today.
Not every toy maker has to create products that perfectly match someone else`s vision. Many of them are permitted to let their imaginations run wild, at least in terms of what the toy looks like. "It`s a tough job, but someone`s got to do it," say the inventors, as they sit on the floor and put their prototypes through the paces.
But there are constraints--such as issues of safety, manufacturability, cost, suitability for the target age group--that toy designers must consider. In fact, on closer inspection, the business of developing toys begins to seem less like play and more like the serious work of designing any product. The task is to come up with a high-quality item that addresses a certain market niche, and to do so as quickly as possible at the lowest cost. As you might imagine, nearly all the large toy manufacturers use CAD to help them do this.
Look through any child`s room, and you`ll see toys that were designed with Pro/Engineer (Hasbro`s Nerf Wildfire; Mattell`s Barbie Airplane, Barbie Digital Camera, and Barbie Jewelry Maker); Unigraphics (Legos); AutoCAD (Aerobie Flying Disk, Aerobie Football); Solid Edge (Playmaxx ProYo yo-yos), and SolidWorks (the Rokenbok system). This list could be much, much longer. But while some toy makers will admit privately to using CAD, they don`t want to talk about it for fear of giving away trade secrets in the highly competitive toy manufacturing business.
To refine the critical linkage for the Down-A-Vator--a pneumatic elevator accessory for Rokenbok construction toys--the lead designer used Working Model to conduct a detailed mechanism analysis.
Toy designers use CAD for the same reasons other manufacturers do. They assemble the product on-screen to check fit, they make rapid prototypes from CAD data, they use CAD files for programs that drive manufacturing machines, and they import CAD models into structural and mechanism-analysis programs to simulate performance.
Structural-analysis software, for example, can predict whether a toy will pass a required safety test in which a 15-pound load is applied. To pass the real-world test, the toy must not break and leave sharp edges. Toy manufacturers can simulate the application of the 15-pound load to the digital model, then reinforce the design if the analysis results show overly high levels of stress.
Toy makers use mechanism analysis to simulate the action of toys with moving parts. Sometimes they do this to address safety concerns and sometimes they do it to make sure they`ve got the motion they want. Sometimes both issues are important, as they were on the Rokenbok Down-A-Vator.
If you haven`t bought toys for a while, you may not be familiar with the Rokenbok system. It was introduced in 1997 and has won numerous awards since then. Basically, it is a construction environment that children use to create buildings, highways, bridges, and chutes. The idea is to create a multi-level environment in which to drive radio-controlled Rokenbok trucks.
The Down-A-Vator is a Rokenbok accessory that uses pneumatic power (no batteries required) to lower a vehicle like a one-way elevator. After the child drives a vehicle onto its platform, the Down-A-Vator smoothly lowers the vehicle one level. Once the vehicle is driven off the platform, the Down-A-Vator returns to the up position.
The Down-A-Vator`s mechanism, a four-bar linkage, was a critical design element because the platform had to remain horizontal while traveling though a very specific range of motion that allowed it to lower the vehicle and raise itself up again to exactly the right height. Moreover, Rokenbok didn`t want any scissoring action that could hurt a child`s finger.
It certainly would have been possible to design that four-bar linkage by hand. Engineers would have made a mockup of the mechanism with cardboard and push pins and fiddled with it until they got the motion they needed. Then they would have performed basic engineering calculations to determine mechanical characteristics, such as how much spring force was needed and where it should be applied to raise the empty platform back to its starting position. Additional calculations would have told them how much damping was needed so that the vehicle didn`t drop too quickly to the lower level. "Engineers have made four-bar linkages without computers," says Dan Aldred, manager of product development at Rokenbok Toy Co. (Encinitas, CA). "But now it`s easier and faster."
Aldred used Working Model from Knowledge Revolution Inc. to perform the mechanism analysis on the Down-A-Vator. At that time, Working Model was only a 2D program, so he actually started the entire design for the product in Working Model. He began by sketching out a 2D line drawing of the linkage, specifying which lines were rigid and which could bend, which line was a spring and which was a damper, and where the pivot points were located. He then specified the size of the spring and the damper and applied a 500-gram (17.5-ounce) load to the mechanism to represent the weight of the truck.
When he clicked "Play," the software ran the mechanism through its range of motion. Besides providing a clear image of the motion path, the software calculated the spring and damping forces and presented them in an easy-to-understand graph. Aldred could immediately see if the mechanism was performing as desired. "The beauty of doing it this way," Aldred says, "was that I could change the size of my spring or damper or the amount of the applied load and run the analysis again. It only took a few seconds for the computer to change the parameters and perform the calculations."
Aldred repeated the mechanism analysis until he had the Down-A-Vator`s mechanism working exactly the way he wanted. He then used the final 2D sketch as the basis for modeling the rest of the product. Today, since Working Model supports 3D, Aldred says he would begin the design by creating a solid model in SolidWorks. He would include the pivot points, locations of the spring, and related information in the solid model, then use the solid geometry directly for the Working Model mechanism analysis.
This example involves a single mechanism on a single toy, but it saved Rokenbok one or two weeks of work, according to Aldred. Multiply that by all the toys with moving parts that are introduced each year and you can see what this software tool alone could mean to toy makers. In this industry, the full spectrum of design-automation technology is becoming a requirement. Taking advantage of technology has become the key to developing products that children will treasure, and delivering them at an ever-faster pace.
Caren Potter is a contributing editor of Computer Graphics World. She can be reached at firstname.lastname@example.org.
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