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Creating a walk cycle with a CAT motion layer

Keyframing absolute animation layers is okay, but it can be tedious. The CAT Motion layer is where the fun really begins. Adding a CAT Motion layer to the list automatically applies a walk cycle to the rig. This is done without having to create any keys; just press the Play button, and you see the default walk cycle.

When a CAT Motion layer is selected in the Layer Manager rollout, the CAT Motion Editor button appears to the right of the layer color swatch. This button opens the CAT Motion dialog box, shown in Figure 39.11. Using this dialog box, you can adjust the parameters of the walk cycle.

FIGURE 39.11

The CAT Motion dialog box lets you alter the walk cycle parameters.

The first panel of the CAT Motion dialog box presents a list of available presets. The buttons at the lower-right corner of the dialog box let you open saved presets. You also can name and save custom presets. The CAT Motion dialog box has its own set of animation layers that are listed in the rightmost pane. Double-clicking a preset opens a simple dialog box with options to load the preset into a new layer or into the existing layer.

The layers work just like those in the Layer Manager rollout with weights assigned to each layer. For example, if you add the default walk cycle and then a new run cycle set to 50 percent, the run cycle is blended with the walk cycle, creating a slower run cycle. You also can open the Curve Editor to change the shape of the weight curves.

Setting global parameters

Clicking the Globals option in the leftmost pane of the CAT Motion dialog box opens a panel of global CAT motion parameters, shown in Figure 39.12. At the top of the global parameters are settings for changing the start and end frame of the walk cycle. Note that these settings are different from the start and end time settings in the Time Configuration dialog box, and they affect only the CAT rig motion.

FIGURE 39.12

The Globals panel of the CAT Motion dialog box lets you change the walk tempo, speed, and direction.

The Max Step Time defines how quickly each step is taken. Low values make the character walk crazy fast, and higher values make a slower, more casual walk. The Max Stride Length sets the distance of each step. These two values together determine the Velocity, but you can't alter the Velocity setting.

The character by default is pointing in the direction indicated on the CAT Parent object, but you can alter the direction that the character is walking by altering the Direction value. A setting of 0 makes the character walk in the direction he is pointing, a value of 90 makes the character shuffle to his right, a value of 180 makes the character walk backward, and a value of 270 makes the character shuffle to the left. The Gradient setting controls the angle that the character is pointing. Negative values make the character point forward as if walking down a hill, and large, positive values make the character walk as if going up a hill.

Walking along a path

The default is to have the character walk in place, but if you select the Walk On Line option, then the character walks forward in a straight line. When the range of frames is reached, the character returns to its starting position and walks the line again. If the Direction value is changed, the character moves straight in the specified direction.

If you click the Path Node button, you can choose a scene object that the character will follow. For example, if you make the Path Node a dummy object, then the character is positioned and walks on top of the dummy object. You can then animate the movement of the dummy object in the scene, and the character follows it.

To make the character walk along a path, you simply need to create a path using the Line tool. Then select the dummy object and use the Animation⇒Path Constraint menu to attach the dummy object to the path. If you enable the Follow option in the Motion panel after making the link, the character turns to