3D Character Animation (part 2)

By Ryan Bird

In the last article, I talked about several theories of how to bring a character to life through emotion and expression. I also talked about creating an idea for an animation and blocking it out with storyboards, and then creating some key poses within a 3D program. Figure 1 shows the key poses that I left off with in the last article.

Figure 1. The three key poses that I am using as a rough outline for my animation

In this article, I work with the key poses from part 1 to get a final animation. I'm using Autodesk* Maya* for the examples in this article, but you can apply these principles to many other 3D animation packages as well.

As I continue to work on my animation, I keep the following theories and principles in mind:

  • Timing
  • Staging
  • Anticipation and follow-through
  • Fluidity between key frames
  • Adding subtle movements

Timing

Whether an animation has to fall within a certain time constraint or can be as long or short as desired, it's important to have good timing. If an animation is long and doesn't have a lot happening, the viewer can easily become bored and uninterested. Likewise, if too much is happening within a short amount of time, the viewer can become confused.

It's good practice to make sure that there's enough time to convey the message or story that needs to be communicated. If I find that I've got too much action going on within my animation timeline, I will either take out some of the action or extend the length of my animation. Similarly, if an animation is running longer than the action that I have, I will either cut the animation short or add action to the scene.

Staging Tricks

When setting up a scene, it's essential to think of the audience. Just like in movies, broadcast, and theater, a scene should be set up to put attention on what viewers are intended to focus on and help them feel like they're a part of what's going on. Poor placement of characters, environments, and props can be distracting and confusing.

In real life, when two people are communicating with each other, they generally face each other. In animation, this kind of staging can be uninteresting. Although it may seem unnatural at first, having the characters aim partially at each other and partially at the camera helps make their interaction more appealing. Figure 2 shows two examples of staging for two characters in a scene. In the first example, the characters are facing each other. Their staging feels a bit detached from the audience, because it's difficult to see their expressions. In the second example, the two characters are doing the same thing as in the first example, but now they're partially facing the camera. Viewers can see more of what's going on in the characters' expressions, which will help the audience feel more involved.

Figure 2. Two examples of staging a couple of characters that are communicating with each other

This is not to say that filming a character from anything but the front is a bad idea. There are definitely instances where it is necessary and can be done correctly, but it's important to keep the audience in mind while staging your characters.

Anticipation and Follow-through

I like to think of anticipation and follow-through as what happens before and after a general motion. Anticipation is the motion that leads up to a general motion; follow-through is the motion that carries that general movement through.

For example, consider throwing a ball. Throwing a ball would be the general motion. The anticipation for throwing a ball would be the character bringing the arm and torso back in preparation for the throw. The follow-through would be the motion of the character coming out of the throw.

With all general motion, there should be an anticipation that prepares a character for that motion and a follow-through that brings the character out of that motion. Generally, anticipation and follow-through happen quickly. When done correctly, the motions complement the general motion and add to the believability of the character's motion.

Fluidity Between Key Frames

The magic of 3D animation allows you to animate a character without having to animate every single frame. In most 3D animation packages, you create a single motion by setting a key frame at the start of a motion, advancing several frames, and setting another key frame at the end of the motion. From there, the software automatically calculates how the motion will look in-between.

Because the majority of animations will have many key frames, it is important to make sure that the motion going on in-between each key frame looks good. Many 3D animation packages give you control over the animation curve created between key frames.

For example, Autodesk* Maya* has a tool called the Graph Editor. You use the Graph Editor to adjust key frames for a selected object as well as the animation curve between the keys. Figures 3-5 show three examples of different curve tangents and how they affect the motion of the object you apply them to.

Figure 3. A linear tangent curve

Figure 3 shows a linear tangent curve. This curve creates a constant motion from one key frame to the next, giving a mechanical look to an animation. I use this type of curve when I am animating something that needs to come to a complete and quick stop (such as a foot landing on the ground) or when I animate something being deflected off of something else (such as a bullet bouncing off of a wall). There are many uses for this type of curve, but be careful how you do it. When used incorrectly, it can make an animation look stiff and robotic.

Figure 4. A spline tangent curve

Figure 4 shows a spline tangent curve, which approximates a nice flowing curve between key frames. This curve gives a nice flowing motion to animated objects that contain several key-framed motions. The majority of your character animation will consist of this type of curve, because it allows the character's movements to look more natural and fluid.

Figure 5. A flat tangent curve

Figure 5 shows a flat tangent curve. This option flattens out the curve at each key frame and is useful for easing in and out of still positions. For example, if a character's hand is resting on a table, then is raised in the air, this type of curve allows the motion of the hand to ease off of the table, then ease into its resting position in the air. The result is a more natural and believable movement.

Additionally, several 3D software packages give you the ability to select handles or controls for these curves, allowing for more manipulation and giving you even more control over a curve. Also, you can mix and match each of these different tangent curve types within an animation curve.

Offsetting Key Frames

As mentioned in part 1, I often like to animate from one key pose to another. Although doing so is a good way to set a nice base for an animation, using this method alone causes all of the motion to happen at the same time and will look a bit static and unnatural. A good way to help remedy this issue is to offset the key frames throughout the character's body.

For example, part of my animation requires the male character to jump in the air after the flower scares him. After setting the base key poses, I end up with a pose of the character in mid air, with his arms extended away from him. When I play the animation back, the character's arms rise at the same time. To give the movement a more natural feel, I go into the Autodesk* Maya* Graph Editor, select the keys of one of the arms, and offset them by a couple of frames. The results show the arms hitting their peak at slightly different times, which feels more natural.

Another thing to keep in mind when offsetting animations is that the offsets should be subtle. As I offset different parts of my character, I do so only by a few frames. Offsetting by too many frames makes the character look too rubbery. Additionally, if I don't use enough frames, the effect isn't as visible and becomes pointless.

Adding Subtle Movements

Another mistake I see in animations is the lack of subtle movement. Understandably, a beginning animator may wonder why it's important to take the time to add such subtle things that may not even get noticed. Although it is true that a subtle movement may not jump out or catch the viewer's attention, in a lot of cases, the viewer will tend to know that it's NOT there. Viewers may not know what's missing, but they'll feel that something is off.

Subtle movements can include eye blinks, eye movement, breathing, hair and cloth movements, and twitches. Although seemingly insignificant, these little things do a lot to add to the believability and overall look of an animation.

Are We There Yet?

When you've added all of these principles and theories to an animation, it's easy to believe that the animation is done. True, it may be close, but there's one more important step to take. Whenever I finish any piece of art, I set it aside for a bit.

Allowing for time to walk away from an animation can give you some time to clear your head of the work you've been focused on for the last several hours, days, weeks, or months. Then, you'll be able to come back to the animation and catch mistakes that were easy to miss after staring at it for so long.

Another thing I like to do is to get the people around me to look at what I've done and let me know if they see anything that should be improved or fixed. The advice of other professionals can go a long way, but I also like to ask family and friends. I always seem to get good responses from both sources.

At this point, I've followed all the steps in this article. I've watched my animation several times and made many improvements. I've even showed it to some fellow animators as well as some family and friends. I'm sure there some improvements that I could still make, but Figure 6 shows my completed animation.

Figure 6. Completed animation from the idea that was shown in Figure 1.

Flexibility

Part of what makes animations great are all the revisions and tweaks that build something into a final product. I have rarely worked on anything that was great the first time. In fact, I know many artists who are never done with their finished work. A lot of times, it seems like there is something that can be improved, no matter how many times it's revised.

The animation I did for this article was no exception to that thought. I started with an idea. Comparing the key poses that I started with in Figure 1 and the final animation in Figure 6, I can see that the general idea is still there, but I did make several tweaks, changes, and additions to the final product.

When animating, it's important to be flexible. Whether it's changes from a client, suggestions from others, or something that you'd like to improve, putting pride on hold and being flexible with your animation can help make a good animation into a great one. One of the most unfortunate mistakes that I see artists make is when they think their first idea is the "only" idea.


Conclusion

Character animation is rarely something that can be picked up and perfected right away. It takes a lot of time and many mistakes to get it right. Even veteran animators will say that they're still learning and growing.

It's easy to get discouraged when starting something new. But, just like anything else worth doing, persistence and practice can go a long way in reaching that goal. By keeping these principles in mind and learning from others you'll pick up along the way, character animation will become more natural the more it's done.


Additional Articles In This Series

3D Character Animation (part 1)


About the Author

Ryan Bird started his career in 1996, at Viewpoint Datalabs*, building content for movies, video games, television shows, commercials, the web, and many other forms of media. From Viewpoint, he worked at Microsoft* Games Studio in Salt Lake City as a Character Lead on several sport franchises. He also worked at Sensory Sweep Studios* as a Team Art Director on some of their biggest titles. Ryan now owns and operates his own business, doing modeling, texturing, rigging, lighting, and animation for professional sports teams, and other big-name companies.

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