ANIMATING RHYTHM AND DANCE

Dancing sometimes intimidates animators, but it actually can be quite fun. If the music is good, you get to listen to it all day, plus you get to dance in front of your computer and call it work. (Of course, if the music is lousy, you still have to listen to it all day.) When you're animating dance moves, the key is make sure that everything happens to the beat. If your timing matches that of the music, then it should all sync up, regardless of where it is in relation to the music.

Understanding Tempo

The key to animating dance is to let the tempo of the music drive the animation. Determining the tempo simply requires a watch. Count the number of beats in six seconds of music. Multiply this by 10 to get the beats per minute (BPM). When you have this, you can determine how many frames you'll need per beat of music. For example, a common BPM is 120. At 24 frames per second (fps), the frames per beat would be this:

24fps x 60 seconds = 1440 frames/minute

1440fpm/120bpm = 12 frames/beat

Here's a quick reference table for a range of tempos.

BPM	24fps	30fps
100	14.4 frames/beat	18 frames/beat
110	13	16.4
120	12	15
130	11	13.8
140	10.3	12.8

This table shows how, at some tempos, the frames per beat is a fractional number. This is one of the problems of a fixed frame rate. The best thing to do in this case is to round up or down to the nearest number and animate at that rate. Unless the shot is extremely long, the characters should sync up within a frame or two, which the audience will not notice.

Of course, if you want to be precise, or if the shot is particularly long, you can certainly read the track and mark down exactly which frames the beat hits. In this case, you will never be more than a half frame off on your sync.
It must be noted that characters can dance with or without music. If the character is dancing an unaccompanied jig of joy, then you can just pick a tempo and go with that. I usually pick 120BPM, simply because it's easy at a half second per beat.

The classic animation studios used to record their music to a fixed metronome. By knowing the beat of the music, the animators could animate even without the soundtrack. Warner Brother cartoons were usually animated at 120bpm, with most major moves occurring in multiples of 6 or 12 frames.

Figuring Out the Steps

Of course, all this math regarding beats per minute is secondary to your character: You first need to figure out how your character will move. Dance steps can be as simple as shaking the character's hips to the beat or as complex as tap dancing.

The one thing about dancing is that it lends itself to cyclical motion. That classic 1970s dance craze The Hustle, for example, is a series of steps that repeat. So is that mid-1990s craze The Macarena. These two examples might be a bit dated and tacky, but they show that many dancers tend to repeat the same moves a number of times. You can animate a single shimmy or a hip shake, for example, repeat it for a few measures, and then switch to other moves. Of course, dancers will never repeat the same move exactly the same way twice, so be sure to use the cycles as a basis for bulding unique motions on each cycle.
Dance moves can be very trendy. What is hip and cool in dance clubs and music videos this year will be totally passe[ag] the next. If you're animating for a music video, for example, you might need to duplicate a specific dance move. In this case, it is probably best to discuss the moves with a choreographer or videotape them as a reference.

There's also the subject of the more formal modes of dancing, such as ballet, ballroom dancing, modern dance, jazz, and tap. All of these have a number of very unique steps, poses, and requirements. At this point, we'll discuss more informal dance moves.

Getting the Hips Moving

Dancing is a very primal activity, and most of it starts with the hips, the most primal part of the body. The simplest way to get a character dancing is to keep the feet planted and simply get the hips moving. The easiest way is to create two poses, as shown in Figure 1: one with the hip neutral and the other with the hip out to the right. Animating between these two poses creates the foundation of the basic dance.

These two simple poses place the character's hips at two positions. Animating between these poses can create the foundation of a simple dance.

To give it a bit more life, you can mirror the extreme pose to create a pose with the character's hip out to the left, as shown in Figure 2. This gives you the opportunity to animate among the three poses and also create patterns. You could simply go from right to left, or you could get more complex, such as right-right, left-left. The possibilities with these simple poses are endless.

Adding a third pose opens up the possibilities. The character can go from right to middle to left, right to middle to right, and so on.

One thing about dancing is that it needs to be fluid, not mechanical. Simply moving between two poses will not be very fluid and will give you something that looks more like calisthenics than dancing. As was mentioned before, no dancer can hit the exact same pose twice. These poses are simply a foundation[md]be sure to mix it up by varying the poses and overlapping the motions of the legs and hips.

Moving on Up

After you nail down the hips, you can add to this foundation with some upper-body motion. Perhaps the character moves her shoulders to the beat as well or throws her hands above her head. All of these can be layered on the basic hip motion (see Figure 3). Again, by creating a few basic arm moves and a few basic hip moves, you have a large palette from which to create a number of combinations. As with the hips, you need to make sure that your upper-body motion isn't too repetitive by mixing up the poses.

After you nail down the hips, you can add to this foundation with some upper-body motion. Adding a bit of arm motion expands on this foundation.

When you're posing the upper body, be sure to keep the poses balanced. If the character has weight on the right leg, for example, the left leg will be bent. This means that the left hip will be low as well, forcing the shoulders in the opposite direction to compensate.

Don't forget the head, which will also bob to the beat. Some dance moves, such as the jerk, require extreme head motions. A good example of using the head is the "Peanuts" TV specials of the late 1960s. The characters had really big heads, and they danced simply by rocking their giant heads from side to side.

Stepping Out

After you have some basic hip motion in action, it is very easy to see where dance steps can come in. One good way of looking at dance steps is as a stylized walk: When the hips move, the character takes a step. A conga line is one example of this type of dancing. Many times, dance steps happen to the beat, but the patterns vary widely. A common variation might be a sequence in which the hips bounce twice for every step, shown in Figs 4 and 5.

In this simple dance move containing a single step, the character starts on both feet, executes a quick kick, and then returns to the original position.

This dance is based on a walk. The character adds extra twist to the hips on each step and also steps to the beat of the music.

Another type of foot motion used widely in dance is the pivot, as shown in Figure 6. Instead of doing a full step, a dancer may just pivot on the toes. This is the basis of The Twist, but it can be applied in many other contexts.

This simple dance is accomplished by pivoting on the toes. The character first pivots on both toes to the left and then pivots back to the right.

This is really just the tip of the iceberg. There are dozens of dancing styles, from ballet to hip hop, to square dancing, and everything in between. In addition to the styles, there are as many ways to dance as there are people. Everyone dances uniquely[md]a character's personality really shows through when she's dancing. As an exercise, try animating a number of characters, each dancing to the same bit of music. Each character will dance very differently, depending upon personality. And, remember -- dancing is supposed to be fun, so you, too, should have some fun with the exercise.