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To animate a set of windmill blades rotating, follow these steps:

1. Open the Rotating windmill blades.max file from the Chap 21 directory on the CD.

This file includes a windmill model created by Viewpoint Datalabs.

2. Click the Auto Key button (or press the N key) at the bottom of the Max window, and drag the Time Slider to frame 50.

3. Select the “prop” object at the top of the windmill in the Front viewport. The blades are attached to the center prop and rotate about its Pivot Point. Then click the Select and Rotate button on the main toolbar (or press E key), and rotate the “prop” object about its Y-axis.

4. Click the Auto Key button (or press the N key) again to disable animation mode. Select the key in the Track Bar located at frame 1, hold down the Shift key, and drag the key to frame 100 (or press the End key).

This step copies the key from frame 1 to frame 100. Doing so ensures a smooth looping animation (even though it spins the prop forward and then backward; I guess it must be a strange wind that's blowing).

5. Click the Play Animation button in the Time Controls to see the animation.

Figure 21.3 shows frame 50 of this simple animation.

FIGURE 21.3

Frame 50 of this simple windmill animation

Another way to create keys is to select the object to be animated and right-click the Time Slider button. This opens the Create Key dialog box, shown in Figure 21.4, where you can set Position, Rotation, and Scale keys for the currently selected object. You can use this method only to create transform keys.

FIGURE 21.4

The Create Key dialog box enables you to create a Position, Rotation, or Scale key quickly.

If a key already exists, you can clone it by dragging the selected key with the Shift key held down. Dragging the Track Bar with the Ctrl and Alt keys held down changes the active time segment.

Copying parameter animation keys

If a parameter is changed while the Auto Key mode is enabled, then keys are set for that parameter. You can tell when a parameter has a key set because the arrows to the right of its spinner are outlined in red when the Time Slider is on the frame where the key is set. If you change the parameter value when the spinner is highlighted red, then the key value is changed (and the Auto Key mode doesn't need to be enabled).

If you highlight and right-click the parameter value, a pop-up menu of options appears. Using this pop-up menu, you can Cut, Copy, Paste, and Delete the parameter value. You can also select Copy Animation, which copies all the keys associated with this parameter and lets you paste them to another parameter. Pasting the animation keys can be done as a Copy, an Instance, or a Wire. A Copy is independent; an Instance ties the animation keys to the original copy so that they both are changed when either changes; and a Wire lets one parameter control some other parameter.

Caution

To copy a parameter value, be sure to select and right-click the value. If you right-click the parameter's spinner, the value is set to 0. •

The right-click pop-up menu also includes commands to let you Edit a wired parameter, show the parameter in the Track View, or show the parameter in the Parameter Wire dialog box.

Cross-Reference

Parameter wiring and the Parameter Wire dialog box are discussed in more detail in Chapter 35, “Using Animation Layers, Modifiers, and Complex Controllers.” •

Deleting all object animation keys

Individual keys can be selected and deleted using the Track Bar or the right-click pop-up menu, but if an object has many keys, this can be time consuming. To delete all animation keys for the selected object quickly, choose the Animation⇒Delete Selected Animation menu command.

Using the Track Bar

The Max interface includes a simple way to work with keys: with the Track Bar, which is situated directly under the Time Slider. The Track Bar displays a rectangular marker for every key for the selected object. These markers are color-coded, depending on the type of key. Position keys are red, rotation keys are