How 3DO creates video games

3DO is a major publisher of video games, with several popular titles for the Nintendo 64 and other this edition of How Stuff Works , we will follow the development of Portal Runner TM, a

How 3DO Creates Video Games

by Jeff Tyson

Video games are enormously popular all over the world In fact, the video game industry is a multibillion dollar a year machine A successful video game, just like a popular music CD, can sell hundreds of thousands or even millions of copies!

You have probably wondered what goes into making a good video game You may even want to get into the business yourself Here are some of the questions that you may be wondering about:

• Where do game ideas come from?

• How many people are involved in making a game and what do they do?

• How is a game developed?

• How does a game get to my local store?

Photo courtesy 3DO

3DO's newest game is called Portal Runner.

To understand the entire process of video game development,

we went to the folks at 3DO 3DO is a major publisher of video

games, with several popular titles for the Nintendo 64 and other

this edition of How Stuff Works , we will follow the development of Portal Runner TM, a new game from 3DO You will learn about the game's technology, how the idea was developed and how the game will be distributed

Where the Game Comes From

All games start with an idea But where that idea originates can be traced to one of several sources:

• An original concept presented by an employee

• An original concept pitched to the company by an outsider

• A sequel to an existing game

• A spinoff based on a character from an existing game

• A game based on an existing character or story (such as movie, TV or comic characters)

• A simulation of another game medium (such as board games and card games)

• A game targeted to a specific demographic

• A simulation of a real world event

• A game designed to take advantage of a specific game platform (such as the Internet or

an advanced interactive game system)

Once the idea is accepted by the company as a viable game, then a preproduction team is

assembled to begin developing the idea into a fully realized game How the game develops depends greatly on what type of game it is The story line and design of a game based on an existing movie or comic character are going to be much more restricted than those for a

completely original game concept Likewise, a simulation based on a real world event, such as a baseball game, has definite boundaries in what can be done

Video games can be extremely different from one another And while there is a huge variety of games available, most fall into certain broad categories:

• 3D Action/Adventure (Portal Runner, Army Men, Tomb Raider)

• Simulation (Army Men: Air Combat, Aero Fighters' Assault, Maestro Music)

• Sports (Sammy Sosa High Heat Baseball, Tony Hawk Pro Skater)

• Strategy/Role-playing/Adventure (Heroes of Might and Magic, Zelda, Final Fantasy)

• Fighting (Mortal Kombat, SoulFighter)

• Puzzle (Tetris, Pokemon Puzzle League)

• Shooter (Defender, Silpheed)

• Platform (Sonic, Super Mario Brothers)

• Racing (Mario Kart, Tokyo Xtreme Racer)

• Conversion (American Arcade Pinball, Who Wants to Be a Millionaire?)

Of course, a lot of games include aspects from more than one of these categories, and a few games are in a category all their own

games in the Army Men series

In the case of Portal Runner, 3DO took a character from one of its most popular franchises and

gave her a spinoff title of her own that falls into the 3D Action/Adventure category The

character, Vikki Grimm, has figured prominently in the Army Men TM universe Portal Runner is not considered a sequel because 3DO is taking one character and building an entirely new game universe around her As you learn about the development of Portal Runner, remember that many

of the steps in the process could change significantly for a different title based on the nature of the game being developed

Planning the Game

The preproduction team normally includes one each of the following people:

• Director

• Designer

• Software Engineer/Programmer

• Artist

• Writer

Sometimes a team will not have every one of these people and other times it will have more than one person in a particular category Another person assigned to the game from the outset is the

producer While the director provides the overall vision and direction for the game and is in

charge of managing all the team members, the producer is in charge of the business side For example, the producer maintains the production and advertising budgets and makes sure that the game stays within budget

The first thing that the preproduction team does is develop the story line for the game Think of

this like writing the outline for a novel The story line identifies the theme of the game, the main

characters and the overall plot Also, areas in the game where a full motion video (FMV)

sequence would help the story along are established An important part of developing the story line is knowing the nature of the game This means that the game designer is typically involved from the very beginning; he/she is responsible for things like:

• identifying traits and features of the game

• the type of gameplay and user interaction that is developed

• how the game will use the technology available on a particular platform (video game

Vikki in a spacesuit

Brigitte Blue, Vikki's nemesis

Portal Runner is a linear game This means that you follow a predetermined path and accomplish

specific goals to complete the game The pattern of the game is: FMV1, Play1, FMV2, Play2, FMV3, Play3 and so on until the end Each play portion has a different look, theme and goal, all

of which combine to form the game world Linear play makes the story line much easier to create

than it would be for a game that branches or has multiple endings Branching games can

contain a series of paths that all lead to the same ending Even more difficult are branching games that can result in one of several different endings, depending on the path taken Of

course, the type of game largely determines what the story line and style can be A puzzle or sports game would not require as detailed a story line as a 3D action or role-playing game

Once the story line is developed, the team creates a set of storyboards A storyboard is a

collection of still drawings, words and technical instructions that describe each scene of the game These include storyboards for the FMV sequences that introduce the story and continue it between the periods of actual gameplay Here are several examples:

A storyboard for the opening FMV in Portal Runner

Close-up view of the storyboard images

In addition to storyboarding the game, the designers will map out the different worlds, or levels of

play, within the game during the preproduction phase The attributes of each world and the elements contained within it are pulled directly from the story line

Developing the Game

Once the storyboards and overall game level designs are complete, the game enters the

production phase The preproduction team expands as needed to include additional artists,

programmers and designers

3DO's artists begin developing the 3D modelsthat will make up the worlds of Portal Runner using

a software application called 3D Studio Max Richly detailed texture maps are created for each object While the game developers at 3DO create the actual game environment using these

models and textures, another division of the company, PlayWorks, will use the same models to

develop the animated FMV sequences for the game

A good example of the models and textures in Portal Runner

FMVs.

Meanwhile, the programmers are writing custom code in C programming language that will

provide the framework for the game objects A lot of code is pulled from the company's library,

which is a bank of already-developed code that can be repurposed for different games Some of

the code is the 3D engine, an application that generates all the polygons, shadows and textures that you see Another piece of code is the artificial intelligence component This is the logic of the game It establishes the physics of the game, detects interaction and collisions of objects and controls movement of the characters Development of the game code is done using a special development version of the particular game system that has increased memory, a SVGA monitor connection, a network connection and a hard drive

All the bits and pieces objects, textures and code are fed into a special utility called a tool

chain that combines the pieces into one big piece of code The tool chain makes code that is executable on a specific platform, which basically means that the game code will actually run on

the game system that it was designed for To test the game, Portal Runner director John Salera uses another specialized game console built for debugging games

The Game World

Portal Runner uses an over-the-shoulder perspective You, as the game player, seem to be hovering in the air slightly behind the character you are controlling As your character moves around, you see the world of the game stretch out into the distance But what you are really seeing is a very clever illusion reminiscent of the backlots of Hollywood!

The world that Vikki can actually interact with in Portal Runner is a very defined area If you could pull the camera view up in the air, you would see that the play area is completely self-contained Other parts of the world that you can see in the distance are actually two-dimensional images mapped onto a flat surface that surrounds the play area like a barrel The sky is created in the same way, by mapping the sky image onto a large dome or cylinder that fits over everything else Look at the example below to get a better idea of how this works

Click on the magnifying glass to move your viewpoint away from the game character As you move farther away, you will see the edges of the game world and the dome that surrounds

it with the city skyline and sky mapped onto it

The production team constantly looks for ways to add cool effects without degrading the

performance of the game A good example of this is the reflections of objects on shiny surfaces, like the chess board in the medieval world of Portal Runner The chess pieces and characters moving around on the chess board appear to have detailed reflections on the polished surface of the chess board What is actually happening is that a second version of each object is positioned upside-down just below the semi-transparent surface of the chess board! The upside-down version moves in concert with the "real" version of the object, providing an illusion of reflection

Polygons, Shading and Skeletons

The vast majority of 3-D objects created for computer games are made up of polygons A

polygon is an area defined by lines To have a polygon, you must have at least three lines

A simple triangular polygon Each point of the triangle is a vertex.

The lines connect a series of coordinates in the three-dimensional "space" the computer creates

The point where the lines connect is known as a vertex Each vertex has X, Y and Z coordinates

• X determines the position relative to right or left in the virtual space

• Y determines the position relative to top or bottom in the virtual space

• Z determines the position relative to front or back in the virtual space

Once each polygon has a set of vertices to define its shape, it needs information that tells it what

to look like There are four common ways to do this:

• Flat shading

• Gouraud shading

• Phong shading

• Texture mapping

Flat shading simply assigns a single color to a polygon It is very simple and fast, but makes the

object look artificial Gouraud shading is more involved Colors are assigned to each vertex and

then are blended across the face of the polygon Since each vertex is typically associated with at least three distinct polygons, this makes the object look natural instead of faceted Look at this example:

The same object with flat and Gouraud shading applied.

You will notice that the ball with Gouraud shading appears much smoother than the flat shaded one But look closely at the outlines of the two balls That is where you can tell that both balls have the exact same number of polygons!

A more complex version of shading, Phong, is rarely used in games Whereas Gouraud shading

interpolates colors by averaging between the vertices, Phong shading averages each pixel based

on the colors of the pixels adjacent to it

Another common technique for determining the appearance of a polygon is to use texture

mapping Think of texture mapping as wrapping a present Each side of the box you are

wrapping is a blank polygon You could paint the box, but it would be very difficult to make it match all the designs on the wrapping paper However, if you take the wrapping paper and tightly cover the box with it, you have completely transformed the box with just a little effort

Texture mapping works the same way Mapping requires the use of another image Essentially, this other image is stretched over the object like a skin Most video game consoles and computer graphics adapters contain a special chip and dedicated memory that store the special images used for texture mapping and apply them to each polygon on the fly This allows games such as Portal Runner to have incredibly detailed 3-D environments that you can interact with in real time

The characters in a game have skeletons Similar to our own skeleton, this is a hidden series of objects that connect with and move in relation to each other Using a technique called parenting,

a target object (the child) is assigned to another object (the parent) Every time the parent object

moves, the child object will follow according to the attributes assigned to it A complete hierarchy can be created with objects that have children and parents Here's an example for a human character:

The closeup shows the skeleton's arm You see that the finger objects are children to the hand object, which in turn is a child

to the forearm object.

Once the skeleton is created and all of the parenting controls put in place, the character is

animated Probably the most popular method of character animation relies on inverse

kinematics This technique moves the child object to where the animator wants it, causing the

parent object and all other attached objects to follow Another method that is popular for games is

motion capture, which uses a suit of sensors on a real person to transmit a series of coordinates

to a computer system The coordinates are mapped to the skeleton of a game character and translated into fluid, realistic motion

Each character's range of motion is programmed into the game Here's a typical sequence of events:

• You press a button on the controller to make the character move forward

• The button completes a circuit, and the controller sends the resulting data to the console

• The controller chip in the console processes the data and forwards it to the game

application logic

• The game logic determines what the appropriate action at that point in the game is (move the character forward)

• The game logic analyzes all factors involved in making the movement (shadows, collision models, change of viewing angle)

• The game logic sends the new coordinates for the character's skeleton, and all other changes, to the rendering engine

• The rendering engine renders the scene with new polygons for each affected object, redrawing the scene about sixty times each second

• You see the character move forward

Finishing Touches

After the basics are in place, the production team begins to refine the game Part of this

refinement involves optimizing the game code, polygon count and logic, including adjusting the

clipping planes and culling The polygon count (number of polygons on screen at the same

time) is a major factor in the smooth rendering and quick response of a game Portal Runner often has more than 50,000 polygons on screen!

Clipping planes determine whether or not polygons in the field of view will be rendered This

depends on how close to the camera the polygons are Typically, the near clipping plane will not

render polygons that are close enough to intersect the plane of the camera This keeps your

viewpoint in the game from intersecting another object and thus blanking out And the far

clipping plane is normally set at the point where the screen resolution causes the details to

become impossible to see There is no need to render objects that you cannot see

Only the portions of the objects in view are rendered.

This leads to another area of optimization While the far clipping plane does not render entire objects that are too far away, culling means that the video game system does not render the parts

of objects that are outside your viewing area For example, when you look at a building, you normally only see one or two sides of the building In a game, you can increase performance by not rendering the other sides of the building until you move around to the point that you can see them And as you move, the game can stop rendering the things you can no longer see

One of the refinements that John Salera said 3DO wanted to make to Portal Runner was to determine where they could eliminate polygons through culling in order to increase the polygon count for Vikki, from 1,500 polygons to 3,000 They want to do this without increasing the overall number of polygons onscreen By increasing the polygon count of a specific object (like Vikki), the object can be made to look smoother and more realistic

Periodically during the development of the game, 3DO sends builds (partially complete versions)

of the game to the game console maker This is done to keep the console maker informed about how the game is developing and to ensure that there are no surprises that the manufacturer might take issue with

As the game nears completion, it enters the post-production phase This phase has several

parts:

• Game versions

• Product testing

• ESRB review

• Marketing and advertising

• Distribution

Once the game is done, an alpha version is sent to designated game testers This preliminary