Interacting with Dinosaurs

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madppiper
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Interacting with Dinosaurs

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INTERACTING WITH DINOSAURS

-Computer Gaming World




Contents
  • 1.Tools of Choice: 3D Studio Max
    2.Innovative Modeling
    3.Building a 360-Degree World
    4.Driving Motion With Al

The modeling and animation challenges involved in creating the Lost World CD games vary greatly from those for the movie

Watching the dinosaurs in the movie The Lost World: Jurassic Park on the big screen most likely will be an awe-inspiring experience for many an audience member. But what if you could go to the Lost World island yourself and have your own encounters with the dinosaurs--or, what if you could take on the role of an actual dinosaur, roaming the island battling enemies to survive? Those arethe experiences game designers at DreamWorks Interactive (Los Angeles) are working to achieve as they develop two titles related to the movie sequel in theme, but yet quite different each in its own way.

The Jurassic theme is, in fact, the only true link between the movie and the games: the development was completely separate (save for the use of some of Stan Winston's maquettes for one title). That's because in developing for film, ILM artists could work with NURBS and enormous model sizes, with no worries about platform limitations or making their dinosaurs move in response to a player's actions. They could do whatever necessary to make those dinosaurs real.

The teams at DreamWorks, on the other hand, had to deal with low-polygon models--at least if they wanted their 3D dinosaurs to move in real time. They had texture limitations, processing power limitations, color limitations--basically, all the issues that game designers deal with on a daily basis.

Interestingly, the two Dream-Works teams operated independently as well, with different goals and game plans. One team focused on a title for the Sony PlayStation, The Lost World: Jurassic Park, which should ship this month. The other team is developing for the PC; their game, Trespasser: Jurassic Park, is expected this fall. The team division was intentional, note the games' producers, the idea being to establish crews who knew how to make the best games for their respective platforms. The two teams did share one goal, however, that being to go beyond what the movie can do by bringing people into the Jurassic era and giving them a chance to interact with, rather than just watch, the dinosaurs.

For those not familiar with the Lost World sequel, it's based on the premise that a secret second island existed on which genetic experimentation took place on a much grander scale. Here, dinosaurs have been breeding and carrying on in their own secluded world--until some unlucky travelers land on the island's beach, and the turmoil starts all over again.

Dreamwork's first shipping title, the PlayStation game, is more about the island than any one character from the film, says Patrick Gilmore, producer. "We wanted to illustrate another dimension of the motion picture," he says, "and that was, what happens to this pristine and untouched ecosystem when humans come into it?"

Throughout the game, the player takes on the role of five different characters through five levels of branching play. Of course, it wouldn't be a Jurassic Park title if the player didn't get to be a dinosaur; notes Gilmore. And indeed, in the first level, the player starts as a dinosaur -- a Comsognathus (Compy). "Compy is a very small-sized chicken dinosaur, like a land piranha," says Gilmore.

Next, the player becomes a human, and it's the human who upsets the island's balance, initiating chaos. Gilmore says his team also chose to include human characters to give some context to the play as a dinosaur.

From there, players move on to be a Raptor, then a T-Rex, and then a human again. Plus there are enemy dinosaurs in the game, says Gilmore, of which were in the film, and more that Dream-Works created just for the game.

To create the models for the ten dinos that appeared in the film, the PlayStation team used the maquettes created by Stan Winston Studios for the movie. "We didn't digitize them," notes Gilmore. Instead, they took photographs of the maquettes from every conceivable angle as well as detailed shots for creating textures. Then the models either were built based on a scan of one of the profile photos, or the artist modeleded it by hand using the photos as a reference.

To create the other ten dinosaurs, the team followed the Stan Winston process except for building the marquettes. Says Gilmore, "We researched the paleontological data, found representative skeletons of the dinosaurs, added musculature to the skeletons, painted skin on top of the muscles, and then added color and texture to the skin to produce the final version of what that dinosaur might have looked like in real wife. We tried to stick close to the Stan Winston process so all the dinosaurs would look like they're from the same world. Then those model sheets went to the 3D artists, who used them to build by hand the geometry that they then animated. The artist also could use the skin that was created for the model sheet to begin to build the textures."



Tools of Choice: 3D Studio Max

The tool used by all the 3D artists for modeling and animation was Kinetix' 3D Studio Max. Gilmore says they went with Max not only for its strong polygonal modeling tools, but also because they needed a standard software platform for which they could write extensive plug-in.

In fact, Gilmore says one of the engineers created a plug-in that let level designers build on the underlying geometry. adding path attributes. Engineers created a host of other plug-ins as well, including file conversion from Max to all the PlayStation formats and a radiosity tool that lets artists place lights in Max that can be interpreted by the PlayStation.

Amazingly, the dinosaurs in the final game are real 3D models, too, not prerendered sprites. Yet they look beautiful and move deftly, responding to every twitch as good game should. Says Gilmore, "When I first started production on this game, I thought we were going to have to do all the dinosaurs pre-rendered as sprites--still doing them in CG, but with much higher polygon counts."

It was Corey Comstock, the lead animator, who stressed that it's not just how many polygons a model has that counts, but how it moves, too, says Gilmore. Comstock was sure he could devise a method for creating low-poly models that look and move with the realism they were seeking. Matt Brown, the lead engineer, also helped to convince Gilmore that real 3D was the way to go. "We decided to at least try, says Gilmore, "and the result was so realistic and stunning that wewent ahead with all the dinosaurs in real 3D, very low polygon. I think, probably on average, the dinosaurs are 350 to 400 polygons."

Although Comstock has worked on a number of platforms, he prefers to use Max along with Digi-marion's Bones Pro for several reasons, one being that Bones Pro lets animators change meshes on the fly.



Innovative Modeling

Initially, Comstock focused on optimizing the model for animation, spending a lot of time on each joint to make sure the model could move correctly. "Basically, it was modeling and remodeling and trying bones to make sure that the geometry all worked. And what came out of that was a technique that all the animators are using to build models. Now, we can build a model in less than a day and start animating right away."

Comstock explains: "The way Bones Pro works is, it affects an area of influence around it. So if you take a Bones Pro bone, and you attach it to the mesh, whatever vertices are close to that bone will be affected. And the area of influence will vary depending on the size of the bone. So a lot of animators and modelers have used fairly big-sized bones. I took a totally reverse approach. I use very very small bones, so I have good control over the amount of vertices that I use. Now, because I use such small bones--I mean, they are really, really tiny and hard to see and even harder to manipulate--I had to build a whole separate skeleton outside of Bones Pro to attach the bones to and to make the geometry work right.

"To build the other skeleton, I used the existing mesh. What I did was, I actually took the geometry and detached pieces of it. [A dinosaur mesh] is all one continous geometry, so I detached the footsection--and that's a foot bone. And I'd detach the ankle section, and that's the ankle bone. So I'd take the whole mesh and detach all the faces so they're separate bones, make them a different color, then attach all the Bones Pro bones to it. So once the model is working properly, I can just hide everything and all I have is a dummy skeleton. The dummy skeleton resembles the original geometry so well that I never even have to look at the mesh again. I can just totally focus on the animation."

Comstock says he's been fiddling around with this idea for awhile on his own. "It was an R&D process; it didn't just start with this project. But it works really good, and what it also buys for you are quick previews. Every animation, I just tweak, look, tweak, look, and to me, that's one of the most important things. What you see is what you get. The closer you can get to that, the better off you are."

The other animators creating dinosaurs for the game were Tim Goodwin and Sunil Thankamushy. Goodwin notes that they experimented some with the IK in Max, but for low polygon models, it just wasn't working. "It was pulling the vertices in weird directions," he says. "So in terms of keeping the feet planted and stuff like that, we would just have to go frame by frame and make sure they were staying and create each keyframe on the right spot and keep the feet planted. But we were still able to get the feet to stick pretty well."

To create realistic movement, the artists used references from nature. For example, for the Bra-chiosaurus, Goodwin modeled the walk cycle after an elephant's walk.

The dinosaurs' textures were created by Matt Hall. Relying on his traditional art background, Hall hand-painted the textures using both Fractal Painter and Adobe Photoshop.

As for the backgrounds, those were done by artists Micah Linton and Dmitri Ellingson. According to Linton, they are trying to keep the levels to about 10,000 polygons. I'm trying to keep onscreen polys to below 600 to accommodate for dinosaurs and enemies and that sort of think," he adds. "It also gives me a little more flexibility in where I want my final cameras, so I can zoom out maybe and get some more interesting angles."

For Ellingson, who has a background in high-res illustration, this was his first low-polygon work. He notes that it also took some experimenting -- about a month or two -- to figure out how the levels would translate from Max to the Playstation. "It never really looks like it did in Max. I'll do a render in Max, and it will look really good, and then I'll get it over to the Playstation, and the polygons will pop and there's Z buffering problems. So there's a lot of work figuring out exactly how the hardware will translate the polygons, and also how it works with texture maps."

Now that he's adjusted to low-polygon design, however, Ellingson likes it. "I like that instant gratification of being able to load it on here and just walk through it in real time. Whereas before, it might take a half an hour to render a scene, and then you figure out it doesn't look right."



Building a 360-Degree World

Work on the Trespasser: Jurassic Park title takes place on the other side of the DreamWorks building. Heading up the team of 22 people (as of press time) is Seamus Blackley, developer, physicist, and producer (not necessarily in that order). Realism is what Blackley's crew is seeking. They're building a 3D version of the Lost World island that player can explore with 360-degrees of freedom. Oh, and there will be 3D dinosaurs to deal with, too. "We're trying to build an environment that really has an emotional punch to it," says Blackley.

The game is based on the premise that the player, who takes on the role of a woman named Ann (it's a first-person game), is the only survivor of a plane crash and has been washed up on the island's shore. Although Ann is familiar with the Jurassic Park experiments, she doesn't realize that she's on the island -- at least not until she starts wandering around a bit. Again, the game has loose ties to the movie, but watching a plot unfold is the last thing Blackley wants players to do. "We're trying to build a world that people really could have lived in," says Blackley, "a world in which you can solve puzzles using your actual real-world intuition, and you feel connected to what's happening."

To make the title immersive, Blackley and his crew have opted not to animate anything. Rather, all animation is completely physics based, and the dinosaurs are "controlled" by artificial intelligence (perhaps the main reasons why this title could not have run on a console). Players will be able to wander around the island and interact "naturally" with their surroundings and the creatures they encounter. "Because you can modify anything in the world and everything has to react to you, there's really no way to plan ahead and do any kind of animations," explains Blackley, who thinks canned animations often look cheesy anyway. "But if you do all of your homework at the beginning and you have a really nice physical simulation happening, you get this plethora of features in the game for free and this huge amount of unexpected play. It's about doing something the designers didn't imagine. It's about things happening that you never thought would happen. You know, you kill one raptor and the other one jumps up on its back and starts attacking you from there, which is entirely possible, but which we don't have to think about because it can just happen."

The world has to react to the player's actions, stresses Blackley. If they want to pile crates to climb into a building, they can, or bust a window with a bat, they can. "And if you throw a rock at a dinosaur, it has to react to it. It can't just run from canned animation," he says.

The physics system also adds a feeling of mass to the dinosaurs. "It's real important that you can tell how much [a dinosaur] weighs and feels. The kinematic stuff, like placing a footstep and having it interpolate between there, if you look, the characters don't have mass when you do that. And even when they say it has mass, and they do all their fancy physics stuff in the SIGGRAPH papers, it's still weightless and really unsatisfying. So getting the weight in there is real art. And that's what our physics is about."

Overall, there will be six different dinosaur species in the game, and then "a bunch of individuals within that," says Blackley, "so you appear to have a huge genetic variety of animals and relatively little work."

Initially, the dinosaurs are modeled using 3D Studio Max. Then once the model is done, it's exported to their proprietary rendering engine. Dream-Works wrote the exporter, too.

Once exported, artists can take the dinosaurs and move them around to see exactly how they will look using the rendering engine. Adds Kyle McKisic, one of the many talented 3D artists working on the project," "We have real-time Phong mapping, as I'm sure Seamus told you."

Indeed, Blackley had pointed out the lack of lighting artifacts on the rendered dinos. "You know, with Gouraud shading and other kinds of approximate shading techniques, you get light artifacts around the vertices. There's nothing like that in our game," he says.



Driving Motion With Al

Blackley notes that the skeleton for each of the dinosaurs is the same, but they can define different joint parameters and other features to differentiate them. The muscles, he adds, are in code. "The muscles that know how to move legs and stuff...have little AIs in them and know how to contract in various ways. And the amount of contraction effects the distance between the vertex and the bone. So when a muscle contracts, the distance gets greater, and when a muscle relaxes, it gets smaller."

Additionally, there's a high-level intentional AI engine that gives commands to the muscle groups. Explains Blackley, "The dinosaurs know how to walk, but they're stupid--they need commands on where to walk and how to move. Or if he gets hit, the AI can damage that joint so the dinosaur limps. So there's really no need to have, like, hit points or a score or anything, because you can see what's happening."

Each dinosaur will have its own parameters for the AI engine. The idea is to give the dinosaurs personalities without completely taking away the player's chances for survival. "For example," says Blackley, "the best way for the Raptor to kill you, if we had an uncon-strained neural net or something, would be to always run at you from behind. Because you know, you have a very small field of view [it being a first-person game], and you can't really tell if something's coming at you from behind. So what the Raptors have to do is realize that and attack you in a friendlier way. You always run up against this wall in game design where people want to do the realistic thing--which is good, because we want to have a realistic feel. But at the same time, it has to be through the filter of actually what's happening and what your ability is to perceive things on screen."

Once the Trespasser team figured out how to create realistic dinosaurs, they were still faced with numerous challenges--such as building the island. According to Blackley, they started by sculpting the island in clay. Actually, art director Terry Izumi, formerly of Disney's Imagineering, built the clay model. Next, the model was scanned, and at press time, they were just starting to get a look at it in Max. Says Blackley, "We had to spend a lot of time discovering both what we needed to do from a design standpoint, and also technically what we could accomplish. Then we had to balance all of that with trying to give the player a sense of the place. So it's been a real struggle, and I think we've finally come up with the answer."

Figuring out how to make low-polygon models look like a rich jungle is no easy task, either, adds Blackley. All the maps, which are truly stunning, are handpainted using Fractal and Photoshop. Says art director Izumi, "Part of the team's philosophy was to hire traditional 2D artists with a great understanding of how to make something dimensional out of a flat surface, which is what they do all the time. Then apply their skills from the traditional world to a low poly-count model and make all this stuff really punch out."

It may seem like the Trespasser team is striving for a perhaps unrealistic perfection with this title, incorporating so much technology (this article barely scratches the surface of what this team is doing). And yes, the team definitely has some lofty goals (and so far seems to be achieving them, too). But perfection is not one of those goals. A number of the artists on this team have worked on games with similar concepts before, says Blackley, and they realize the most fun is when things "screw up." "Like, when a dinosaur bangs its head against a tree because it reacts too late and things like that--it's not dumb, it's cool. It's like, wow, it's a dumb animal. That's awesome! So it's not when things are working perfectly that the world is really interesting.

"I think that's one of the things that's kind of unsatisfying about a lot of preanimated games, where all the motion is really perfect," he continues. "It's when things aren't exactly behaving perfectly and the dinosaur is kind of confused and looking around, trying to find out where you are...I mean, that's when it's real."

~~~~~~~~

By Donna Coco


Donna Coco is a CGW senior associate editor.





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Image
PHOTO (COLOR): Artist Matt Hall, who created all of the textures for the dinosaurs in the PlayStation game, created this image of one of the game levels as well.

Image
PHOTO (COLOR): This image is from the upcoming PC game, Trespasser: Jurassic Park.

PHOTO (COLOR): The dinosaur on the opposite page was used to create the model for the Staurikosaurus in the PlayStation title, The Lost World: Jurassic Park.

Image
PHOTO (COLOR): Both of these images are from the upcoming PC title, Trespasser: Jurassic Park, a game that makes innovative use of artificial intelligence technology.


Image
PHOTO (COLOR): This image is from the upcoming PC game. Trespasser: Jurassic Park. The dinosaur on the opposite page was used to create the model for the Staurikosaurus in the PlayStation title. The Lost World: Jurassic Park.

PHOTO (COLOR): Both of these images are from the upcoming PC title, Trespasser: Jurassic Park, a game that makes innovative use of artifical intelligence technology.



Image
PHOTO (COLOR): Artist Matt Hall, who created all of the textures for the dinosaurs in the PlayStation game, created this image of one of the game levels as well.


Image
PHOTO (COLOR): These three screen shots come from the PlayStation title, The Lost World: Jurassic Park.




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Copyright of Computer Graphics World is the property of Penn Well Publishing Co. and its content may not be copied or e-mailed to multiple sites or posted to a listserv without the copyright holder`s express written permission. However, users may print, download, or e-mail articles for individual use.

Source: Computer Graphics World, Jun97, Vol. 20 Issue 6, p42, 5p


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