Anticipation: Getting Ready to Move
The principle of anticipation is an important part of telling the story in its linear sequence because it sets up the audience for the next thing that the character is going to do. Anticipation tells the audience visually what the character is thinking because those thoughts are acted out as the character gets ready to take action.
In the case of the ball, it starts out squashed and expands to its full size within 10 frames of each bounce impact with the ground plane. The ball's squash happens right at the moment of impact, without any anticipation. It still looks okay, but adding a frame of anticipation just before and just after the bounce impact will create a smoother and better animation.
The ball anticipation is a simple example, and anticipation in its more complex forms is critical in setting up an audience for a visual gagin getting them to believe that something is going to happen by the anticipatory action and then making something altogether different happen. For example, perhaps the ball doesn't bounce on the last frame; instead, it splats down like a dollop of ice cream. Like a horse rearing up before it gallops away, anticipation is the visual equivalent of "ready-set-go," where some sequence of animated movement occurs before the main animation actually takes place.
Creating Anticipation and Using Be´zier Tangent Controllers
The next step in this exercise is to fix the interpolation of the keys and to add in the anticipation keys before and after the ball impact with the surface.
1. Move your time slider to frame 0, and change the In Be´zier controller in the Motion command panel Scale Key Info section to Step. Leave the Out controller set to Smooth, as shown in Figure 16.
Move the Time slider to frame 1, and create a new Scale key at this position. This is the first anticipation key just after the ball leaves the ground at frame 0. Change the Z Value of this key to 65%. This tells max to start a gradual increase in the ball's size, anticipating its return to full size at frame 10. The In and Out tangent controllers should be set to smooth.
Move the Time slider to frame 10, and leave the In tangent set at smooth; change the Out tangent to Step. This will solve the rubbery problem that was seen before the tangent was changed by telling max that as the animation moves away from frame 10, the ball is to remain at 100% size until the next keyframe.
Move the Time slider past frame 30 to frame 44, one frame before it impacts the surface of the ground plane. Create a new scale key, change the z-axis value to 65%, and change the In tangent to Step and the Out tangent to Smooth. Changing the In tangent to Step tells max that the ball is to be full size starting at frame 10 and should remain full size until frame 44, when it scales down to 65% in anticipation of striking the surface at frame 45.
Move to frame 45, change the In and Out tangents to Smooth, and move the Time slider to frame 46. Create a new Scale key at 46, and change the z-axis value to 65%, as before.
Move to frame 55, the next point at which the ball reaches full size, and change the Out tangent to Step.
Figure 16 Changing frame 0 sets up the paradigm for the rest of the repetitive keys needed to create the proper interpolation and anticipation for the bouncing ball. Feel free to experiment with the Be´zier Tangent controllers; it's an effective way to understand what they do.
You'll notice that because the Be´zier Tangent controller in the Out box of frame 1 and the In box of frame 10 are set to smooth, the ball elongates a little between the two keyframes. This is a result of the Smooth controller interpolating the frames between the keys, which creates the stretch effect needed in the ball animation.
You could continue adjusting the existing frames and creating new anticipation keyframes before and after the ball impacts the surface. If the next shortcut step seems too tricky for you, use the information in the previous steps to create anticipation keys with z-axis values of 65% at frames 134, 136, 179, 181, 224, 226, 269, 271, and 314. Don't forget to change the Be´zier tangents following the pattern set by the first 55 frames. Here's the shortcut I use when creating multiple keys that are repeating the same animation when I am not using Parameter Curve Out-of-Range Types.
Copying and Moving Keys in the Track Bar
Individual keyframe dots shown in the Track Bar can be selected and moved by clicking and dragging them in the bar. This is a simple way to adjust your keyframe timing and location. If you hold down the Ctrl key while selecting the keyframes, you can choose multiple keys at the same time; you can also drag a selection rectangle around the keys to select them.
Holding down the Shift key while moving a key or multiple keys will copy those keys to a new location of your choosing within the Track Bar. This follows the same Shift-drag max convention for selecting and making clones of geometry.
The problem with the Track Bar is that the keyframe dots are so small that it is sometimes difficult to get the exact ones you want. The frames that you want to copy, in this case, are the second and third anticipation keys at frames 44 and 46. If you can carefully select these frames, go ahead and do so; however, the easiest way is to open the Track View Editor, which is now full of many keys (see Figure 17). You'll use the Region Zoom icon to zoom in on the keys you want to copy. Move the time slider to frame 45this will help you see where the keys are in the Track view.
Figure 17 The Track View Editor, Time Slider, Track Bar, and Motion Command Panel are part of a linked system of animation tools. What you do in one affects and changes the whole system.
Zoom in on the keys at frame 45; then right-click in the Track View window to exit zoom mode and select frames 44 and 46, as shown in Figure 18. When you have finished selecting the frames, you can click on Zoom Horizontal Extents to return to the complete view of all the keyframes.
When you copy the keys in the Track Bar, the cursor changes into the horizontal move arrow, shown in Figure 19. Copy these two keys to their new positions bracketing frames 90, 135, 180, 225, and 270. When you get to frame 315, just copy one of the keys at frame 314.
Figure 18 Copy these two frames in the Track View or the Track Bar to complete the ball animation.
Figure 19 Using the Track View or Track Bar to edit the placement of your keys is an important skill to master and will make your animation work in max more productive.
With the animation complete, try your hand at texturing and lighting the shot, and render out a preview or a full AVI movie of the result. You can find this complete example saved as Ball Bounce 2.max in MAXWorkshop\Models\Workshop Examples. An AVI titled Ball Bounce 2.avi can be found in the AVI's folder.