For Troopers, Hayes modified and refined the DID system to make it more user-friendly, and created new armatures to represent the four-legged Warriors. "We mostly made mechanical improvements," Hayes says. "We did everything we didn't have time to do on Jurassic Park. We built extra armatures, so if anybody's puppet broke, we could swap in a new one and repair the old one. We changed the positions of the encoding devices and sensors, and we streamlined the system and improved the speed of its response quite a bit; everything's much faster. There's only a quarter-second delay from the time the animator moves the DID armature to the point when you can see the result on a monitor. There were three animators using the DID, and they could do pretty tight performances. We put a lot of effort into getting most of the bug parts on the DID armature, though some secondary animation had to be done to add the various smaller attack claws. It usually took a couple of days to animate a shot."
To create the Warriors, the DID animators used the system primarily to animate the bugs' keyframe positions. For example, an animator would pose each leg in its beginning, middle and end position, and the computer would fill the gaps in between. Hayes also devised a variation of the system for real-time puppeteering. This technique, more closely related to motion capture than puppet animation, enabled Tippett Studio to quickly generate shots of the bugs leaping or snapping their jaws recalling the digital rod-puppet method Boss Film used to create its CG alien creature in Species. "The animators manipulated the DID puppet in real time," Tippett says. "Depending on the complexity of the shot, sometimes two or three people would puppeteer them."
Since their work was instantly reviewable and each performance could be saved, the DID animation could be continuously refined as long as time and money permitted. Tippett's animators could critique quick-shaded versions of their shots, then go back and redo parts of the performance.
In shots with multiple creatures, the animators still used a single DID armature to build up layers of animation. "We'd do one performance and use that as reference," Hayes states. "Then our DID software allowed us to play back the prerecorded performance while the animator animated the new one."
For the larger "crowd scenes," which featured no less than 30 and upwards of 1,200 Warriors, Tippett's crew used procedural animation to generate the swarming hordes. "We created bug walk cycles which we could run over the terrain and rocks," Tippett explains. "We graphically tried to make them appear to be doing the different kinds of things that warrior ants do, so we offset the cycles and determined interesting flows and paths so they almost look like a river of living stuff."
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