How Animation Software Works

In 1962, MIT Ph.D. student Ivan Sutherland gained temporary access to an old TX-2 computer. The TX-2 was a giant multitasking mainframe created in the 1950s that was used for military applications, air traffic control, payroll and census processing, and various other tasks. The TX series machines were some of the first computers to have monitors. Sutherland used it to create a program called Sketchpad, which enabled the user create line drawings and make them move on a computer screen with a light pen and tablet. It was, in effect, the first interactive animation software. Although conceived for engineering applications, he noted in his dissertation that "it might be exciting to try making cartoons." He even drew a face with an animated winking eye as part of a demo [source: Sito].

But it would be a while before anyone was creating animations with user-friendly software applications. Most computer graphics for the next couple of decades were created by people with programming skills and access to expensive government, corporate or university mainframes. One early wireframe animation of a satellite orbiting a planet was created by Edward E. Zajac for Bell Labs around 1963 using the FORTRAN programming language. The first 3-D rendered movie, a short called "A Computer Animated Hand," was created in 1972 by Ed Catmull and Fred Parke at the University of Utah. It featured a moving wireframe hand and face, as well as those same models covered in smooth skin. Not surprisingly, Catmull would go on to co-found Pixar.

A one-time student of Ivan Sutherland named Jim Blinn did some of the earliest television CG work while working for NASA's Jet Propulsion Laboratory (JPL). First, he made realistic computer animations of the Voyager missions that aired on news programs starting in 1979, and then he and his team at the JPL contracted to do graphical renderings for Carl Sagan's 1980 PBS series "Cosmos." (Blinn would later develop "Blinn shading" and an enhancement to texture mapping called "bump mapping.")

It wasn't long before some of the top computer graphics talent started working in the film industry for outfits like George Lucas's movie special effects powerhouse, Industrial Light and Magic (ILM), originally created to do special effects work for "Star Wars." Jim Blinn and Ed Catmull both worked for Lucasfilm, though at different times. It was while Catmull was there in 1986 that Steve Jobs purchased Lucasfilm's Computer Graphics Division and it became Pixar. Pixar's "Toy Story" (1995) was the first completely CGI full-length film.

Both ILM and Pixar, along with other emerging computer graphics houses, would develop lots of technical innovations for use in computer animation, some of which eventually filtered into commercially available software. The advent of small, affordable personal computers was another major step that made this possible. Computer animation is now routine in television, movies and advertisement, and it's entirely possible to create in your own home.

Several programs that let users create computer graphics were released in the 1980s, including Autodesk's AutoCAD in 1983, MacPaint in 1984 and Adobe Illustrator in 1987. Adobe Photoshop was developed in 1988, and version 1.0 was officially released in early 1990. Autodesk even released an animation program called AutoFlix in 1986.

In the 1990s, more animation packages began to hit the market. Autodesk 3-D Studio DOS came out in 1990 and later became 3-D Studio Max, a 3-D animation software full of features that was released in 1996. In 1990, NewTek released Video Toaster, which included LightWave 3-D, for Commodore's Amiga computer. LightWave 3-D was later ported to Mac and Windows. Alias's 1993 software PowerAnimator, used on the breakthrough CG film "Jurassic Park," among others, was eventually combined with two other software applications (Advanced Visualizer and Explore) to become Maya. Maya was released in 1998 by Alias/Wavefront and is now owned by Autodesk. Newer versions of all three are still in use as of 2015. Maya is even used at major effects outfits like Weta Digital, the company that created the CGI for Peter Jackson's "Lord of the Rings" and "Hobbit" films.

A product by FutureWave Technologies called FutureSplash Animator was purchased by Macromedia and remade into the 2-D animation package Flash around 1997. It's now Adobe Flash, a 2-D animation package still in wide use.

Lots more 2-D and 3-D animation software packages are available, including DigiCel's FlipBook, SmithMicro's Anime Studio, Toon Boom's Harmony and Animator, MAXON's Cinema 4D and Blender, the latter of which is a completely free open-source application that can be used for 3-D modeling, animation, rendering and more. You can pick the one that best suits your needs and get to work.

Whether you're using software or animating free-hand, there are some basic concepts that apply. Knowledge of basic physics, especially the Newtonian laws of motion, will help make your characters move and interact in believable ways. It's important to know how objects will behave when they bump into each other, or when forces such as gravity and friction act upon them. The attributes of the objects themselves (think size and mass) will also affect how they should move and interact in your animated world.

One commonly cited animation principle is that many actions in nature follow an arc, including animal and human motions. The study of how body parts or other grouped objects and their joints move to get from one place to another is called kinematics, and it's a term you'll hear often in relation to animation and animation software. To some extent, animators learn these rules so that they can creatively break them. Rather than striving for entirely realistic action, they often exaggerate movement, at least a little, to keep things lively.

Animators use a number of other methods to make interesting animations with fluid motion. For instance, rather than have things move at constant speed or start and stop abruptly (which is rarely the way things move in the real world), the animator will incorporate slow-in and slow-out, meaning he or she will make them start slowly and accelerate to a faster speed, or decelerate and slow down before coming to a complete stop. Follow-through and overlapping can also be used to create more realistic and interesting motion. Flexible objects, or objects attached to other objects, will not move all at once. One part might start the motion and the other is pulled along, arriving at its final position (or follow through) a bit later than the first part. For instance, the upper part of a leg moves, followed by the calf, then the foot, with hair or clothing lagging behind and catching up after a person moves. There's also a lot of natural overlap to action. Rather than having a character complete one action before starting the next (which would likely look unnatural and boring), he can begin the next action before the last ends.

Two other concepts often applied to non-rigid objects in animation are squash and stretch, which are flattening and lengthening of the object, respectively. For instance, a ball might squash a bit when it hits the ground, or a balloon might stretch a bit when pulled by its string. Another, anticipation, is used to broadcast an upcoming motion by moving an object or character in one direction just a little before it makes a larger motion in the other direction.

Animators have always had to plan out the timing of actions to build suspense or to make sure things happen at the right pace. They also have to take scene composition into account (including contrast, lighting, perspective and what objects are visible) to build the right mood, convey the intended story and make sure that the audience can tell what's going on.

A lot of old-school animation was done by having the main artists draw out key frames that showed the beginnings and ends of motions, and having more junior artists draw the more numerous in-between frames that fill in the action from the first key frame to the next.

Another technique used in traditional animation was layering using see-through animation cels. Artists would create background images that could be reused, and then they'd draw the foreground elements and characters on animation cels that could be layered over the backgrounds and photographed. This means the background wouldn't have to be drawn in every time.

These, along with many other basic animation concepts and methods, are still used by people animating on physical media and on software, and in some cases they have been worked into the basic functionality of the software packages.

Animation software provides you with computerized versions of old tools in addition to some nifty new tools, but it doesn't do the work of the animator. Someone still has to design and create characters, backgrounds and other elements and then carefully arrange them over a series of frames to create a moving picture. Everything is digital instead of physical (a mouse and computer screen instead of pen and paper, for instance), but the methods are very similar, and it's still a lot of work.

Like any activity involving a computer, you have to tell it what to do, but animation software does include some handy time-savers. Anything involving math (including algebra, geometry, trigonometry, calculus and physics) can be represented by algorithms, which can be programmed into software. All of these fields come into play in software's ability to create computer graphics and animation, and they've also been used to build a lot of handy quick tools and automation into the various software packages.

Animation software lets you make nearly instantaneous adjustments to frames you've already modified, something that may have involved physical erasure or starting over with a new animation cel in traditional animation. The applications give you tools to draw or create elements using your input device of choice (mouse, trackpad or pen tablet). Cut, copy and paste features let you quickly rearrange or duplicate objects or parts of objects, again without the physical labor that would have been required in the old days. You can use a selector tool to drag already-created objects to the screen rather than redrawing them. You can click on lines, points or Bezier curves and drag to resize or otherwise modify objects. These functions aren't limited to objects. You can also sometimes cut or copy and paste whole frames to move a scene or create looping motions.

Another handy tool called onion skinning or ghosting allows you to see your objects in the current frame along with the objects at their positions in one or more previous frames to help you visualize how they are going to move from frame to frame. You are basically seeing objects from multiple frames on the screen all at once.

The software can also interpolate (or auto-create) the in-between frames, whereas in the old days, someone had to manually create art for every frame. The lack of the need for physical media also provides you with limitless virtual art supplies, including a vast palette of colors, which frees you up to create anything and everything you can imagine, given enough time. With enough processing power, skilled animators can now create and display fantastic things that wouldn't have been possible in the past, with an increasing level of realism (if realism is the aim).

Some animation applications are easy to jump into after reading or watching a brief tutorial, and others have a steeper learning curve. In any case, practice and study are required to master any application, as well as the art of animation itself in any medium.

Most animation software applications have similar features, although the specific tools that are available and their locations in the menus, toolbars and palettes will vary from app to app. They are similar in layout to a lot of Windows or Mac apps, but with lots of tools specific to creating graphics and animation. There may be tools to draw freeform (pen, pencil and paintbrush tools), erase things, fill areas with color and quickly create specific geometric shapes (flat or three-dimensional, depending upon whether you are working in 2-D or 3-D animation software). Often you need only consult the help menu, a manual or the Internet to find what you are looking for. The names for the items may vary just enough to elude you for a while, so walkthrough tutorials for the specific software you're using are also advisable.

In animation software, there's generally a timeline across your application window, usually by frame number, that allows you to time what happens and when. If you have your frame rate set to 24 frames per second (fps), frames 1 through 24 will represent the first second of the animation, 25 through 48 will be the next second, and so on. You can divide the frame number by the frame rate to see approximately how many seconds that frame is into the animation, or divide the number of frames that make up a particular segment of the animation by frame rate to find the length of the segment.

The concept of the key frame has been carried over from traditional animation into animation software. You generally insert key frames anytime there's a change, such as an object appearing or a motion beginning or ending, but you can insert as many key frames as you want. If you want to hand draw every frame, all the frames can be key frames.

Scrolling across the timeline (usually by clicking and dragging with the mouse or other input device) is called scrubbing. In most software packages, you can scrub across the timeline to see your animation in motion, or you can click on individual frames in the timeline to view what's in that frame. This is very handy for testing as you go.

You build your animation in an empty area in the animation software window sometimes, but not always, referred to as the stage. Anything put there will show up in your animation. There also might be an empty space around the stage where you can put elements that won't appear on screen until you move them into the main area.

The concept of layers has also carried over from old school animation. You can create virtual layers containing different elements that can be moved to the background or different foreground layers. This makes it easy to place objects or characters in front of or behind other things, helps you keep your objects and characters separate from one another, and, like in the old days, lets you set a background to run for a number of frames while you make changes only in the foreground layers.

The real first steps should involve a lot of planning and design. You'll need a story, characters and settings. You may even want to storyboard out your whole cartoon. But whether you want to meticulously plan the whole thing or wing it as you go along, once you're ready to start, there are some basic steps to get you animating.

You'll likely need to set the frame rate (the number of frames that will play per second) and the dimensions of your animation (often, but not always, in pixels). You might also want to set the length of your animation (either in time or in frames). The settings depend in large part on what medium you are animating for (TV, theatrical release, web video or banner ad, for example) and how you want the final product to look.

Frame rate will determine how many frames you have to create for each second of playtime and will affect how smooth the final animation appears. Some standard frame rates are 24 frames per second (fps) for theatrical film, 25 fps for PAL video and 30 fps for NTSC video (U.S. standard format). Something lower, like 12 or 15 frames per second, can be used to decrease the number of frames you or the software will need to fill. You can go even lower, but the lower you go, the more jumpy the animation will look. You may even want to do something called "animating on twos," where you keep a 24 fps setting but only animate every other frame. The rest of the frames will just be copies of the previous frame.

The easiest way to start animating is to create a simple object using your software's shape or draw tools (or import one created or saved elsewhere), put the object somewhere in your working area and insert a keyframe into the timeline (the method of inserting keyframes will vary by software, but you can usually do it using a drop-down menu or quick key combination). Then drag the same object to a different position and insert a new keyframe somewhere farther down the timeline. You might have to tell the software to create a motion tween or something similar, or it may do this automatically. A tweenis an object you can put into two different frames and the software will automatically create the frames in between to get your object from point A to point B.

When you scrub across the timeline or play your animation, you will see your object move from the first keyframe to the next. And so you have your first animation, albeit a short and simple one. Rather than moving the object to a new position, you could also change the parameters on the object from one keyframe to the next, for instance, scale the object down or make it a different color. In those cases, rather than see the object move, you'd either see it shrink or slowly change color. And some programs will let you place two different shapes or objects in two keyframes, and the software itself will figure out all the in-between frames to morph one into the other. You can add more keyframes and manipulate your object further to make the motion, or morphing, continue until you have a longer animation.

Those are just some very basic steps to make something move or change on screen. You can use all the tools available in the software to build more complex objects and make them go through complicated motions and interact with one another. There are a lot of bells and whistles in most animation software that you can use to add to or enhance your final product.

With a lot of animation software, you can build and manually (or, rather, digitally) manipulate objects, change myriad settings to affect them and even program actions using built-in programming languages and interfaces (such as Adobe Flash's ActionScript). But you don't have to use the programming features, so computer science skills aren't required.

Aside from the basic drawing and shape tools, modern animation software contains a lot of other ways to manipulate the objects and motions you've created. For one, you can edit the automatically created in-betweens to better control motion and transformations using something called curves. Usually these are available under something called a curve, graph or animation editor. The editor will show visible curves that represent various attributes of your objects on various axes (for instance, in 3-D animation software, you might have three separate curves for rotation and three for translation, one each for the x, y and z axes). You can grab and move these curves to change things like scale, rotation and position to have finer control over changes in objects and their motion. Some software lets you select and apply preset curves that change the animation in some predictable way, like adding slow-in or slow-out motion, constant change (with linear curves) or sudden stops and starts (with step curves).

The modeling tools in a lot of animation software let you create assemblies of smaller parts that are grouped together, and to define the relationships between these parts in a hierarchy. Usually the relationships are that of parent, child and/or sibling. When the parent part moves, the child parts, and any of their children, follow suit. You can set joints or pivot points to allow for rotation and define things like how far they will move in any direction. You can even set a pivot point outside of an object to make it rotate around something (possibly handy for space scenes). Placement of pivots also controls from what point an object will scale.

This allows you to build rather complex objects (like vehicles) and characters (robot or animal) and to make them move in realistic ways. This is sometimes called character rigging, and these rigs can be reused. In a lot of 3-D (and some 2-D) modeling and animation software, you can create skeletons using hierarchies of bones and joints and wrap them in an outer skin. They aren't literal bones and joints, but wireframe renderings. You can then move various parts of the skeleton, and the skin will move and deform accordingly. In some software you can even define things like muscle for even more fine-grained skin deformation and body movement. And when things don't move as you like, you can go in and tweak the effect of one area or another with changes in number settings or sometimes even strokes of an erasure-type tool.

A lot of software packages also contain lots of motion control settings, including built-in motion effects like squash and stretch controls and preset motion paths that you can put objects on rather than having to create them manually. Many also include something called inverse kinematics, which allows for very complex motions, like walking, that are hard or impossible to get right with typical hierarchical motion (called forward kinematics). If you let the parent object (say the hip) just drag its children (thigh, calf and foot) along when it moves, the motion will be unnatural. Inverse kinematics basically involves reversing the hierarchy and putting the child in charge, so when you want a character to start walking, you move its foot into position and the rest of the leg follows appropriately. Some software lets you toggle which type, forward or inverse kinematics, a hierarchical structure will use at a given point.

In a lot of applications, you can add virtual light sources of various types (to emulate spotlights, lamps or the sun, for instance), and the software will add shading and shadow appropriate to the location of the light.

Most applications also allow you to lay down audio tracks on your timeline and scrub through them (listen to bits back and forth) to work on timing and sync up your animation to the sound or music.

The software runs the gamut as to complexity, number of tools and built-in functions, and expense, but the most used animation software applications all cover the basics and then some.

There are a lot of similarities between 2-D and 3-D animation techniques and software. In most cases, both types let you create graphics using similar tools. Both will generally interpolate the frames in between key frames. Both tend to have a timeline that you can add things to and scrub through to see your work in action.

But there are also some notable differences. In 2-D animation software, you're working with flat shapes that follow the plane of your screen. You can only plot things along two axes (the x-axis and y-axis), and your camera is set to one perspective (looking straight at the screen). You can emulate 3-D-like motion by using perspective tricks, like scaling a character down progressively to make him appear to move away from the audience. But if you want to see your objects and characters from different angles, you have to draw or create different views of the characters from all the angles you need.

In 3-D, you gain a third axis — the z-axis. This allows you to create and work with 3-D objects and characters and to move them around in three dimensions (albeit virtual ones). The shape tools will create 3-D objects such as cubes and spheres rather than flat ones like squares and circles. If you want to see a character from different angles, you don't draw multiple versions. You create a fully realized 3-D model of the character, and once it's on your screen, you can rotate and pivot it around as you like. You can also set the camera perspective anywhere and look at your scenes from any vantage point.

Saving out your final movie in a 2-D program is a relatively simple process because you've laid out every frame as-is on the 2-D stage. In 3-D animation software, the program has to render all the 3-D models on screen into 2-D images for each frame from the camera's point of view for that shot. You usually have to set camera and light source information before rendering.

If you want to get really fancy (and high budget), you can use motion capture, and film actors covered in sensors with special cameras. The recorded motion data is imported into the animation software to create a 3-D model with realistic motion. With 2-D, the closest comparable technique is importing video, putting it on a layer and tracing over it to capture the motion frame by frame (a technique called rotoscoping).

There are even some software packages that let you work with both 2-D and 3-D elements together, or zoom around in a three-dimensional environment containing 2-D objects. And a lot of 2-D packages are implementing character rigging with skeletons now, too. They can just be used to control your character's movement and deformation on two axes rather than three.

When creating a stand-alone animation, 2-D versus 3-D may be a choice of style or of budget; you might not be able to afford the time or hardware and software required to render 3-D movies. Animation software that can render 3-D is a necessity when creating graphics to composite into live-action movies, however, and is becoming more and more common for animation of cartoons.

The goal of animation isn't just to move stuff around on a screen. It's usually to tell a story. Whether an animator goes with old-school physical methods or computer software, the work is still all about the narrative.

With enough practice and the right tools, you can animate anything from simple 2-D black-and-white line drawings to stunningly rendered 3-D color graphics. And more and more software packages are becoming viable for home use. Some are free (like Blender), some are now available for a monthly charge (like Adobe Flash) and a lot of others are just a few hundred dollars, although there are packages in the thousands, as well. Thankfully, many animation software companies have multiple versions (from light to professional), and a few let you try out their software for free for a trial period.

Which software you pick should be based on your final goals, your skills, your budget and what your computer can handle. There's a lot of overlap among some of the different animation applications, so there's likely more than one that will do for your purposes. You might even want or need multiple hardware and software tools to handle separate tasks like building your models, creating music and syncing it to your animation, rendering your final animation and editing your video. Or you might find one application that handles all of these adequately for your project.

No matter what, you'll have to block out some time. Your software and hardware processing power, length of the film, type of animation and how many people you have working on it all come into play. Creating animations with software can take anywhere from a few hours for a short and simple 2-D animation in Flash to several years for a full-length computer-generated movie like a Pixar film.

Not that most of us are going to whip out a Pixar film alone, even if we have years to put into it. But as time passes and the graphics magicians come up with better and better algorithms and tools, even the software you can run at home is getting more robust and incorporating more realistic hair, skin, texture and motion effects. Some of them are also getting cheaper and more user-friendly. One day, it may be that our imaginations are the only barriers to creating stunning, professional-level animations.