Animation Basics

Max can be used to create some really amazing images, but I bet more of you go to the movies than to see images in a museum.

The difference is in seeing moving images versus static images.

In this chapter, we start discussing what is probably one of the main reasons you decided to learn 3ds max in the first place — animation. Max includes many different tools to create animations. This chapter covers the easiest and most basic of these tools.

Using the Time Controls

Before jumping into animation, you need to understand the controls that make it possible. These controls collectively are called the Time Controls and can be found on the lower interface bar between the key controls and the Viewport Navigation Controls. The Time Controls also include the Time Slider found directly under the viewports.

The Time Slider provides an easy way to move through the frames of an animation. To do this, just drag the Time Slider button in either direction. The Time Slider button is labeled with the current frame number and the total number of frames. The arrow buttons on either side of this button work the same as the Previous and Next Frame (Key) buttons.

The Time Control buttons include buttons to jump to the Start or End of the animation, or to step forward or back by a single frame. You can also jump to an exact frame by entering the frame number in the frame number field. The Time Controls are presented in Table 30-1.

Table 30-1: Time Controls

Toolbar Button	Name	Description
	Go to Start	Sets the time to frame 1
	Previous Frame/Key	Decreases the time by
		one frame or selects the
		previous key

30C H A P T E R

In This Chapter

Controlling time

Using the animation mode buttons to create keys

Using the Track Bar

Viewing and editing key values

Using the Motion panel and trajectories

Enabling ghosting

Animating materials

Using Previews

Creating custom parameters

Wiring parameters with manipulator helpers

Using animation modifiers

Continued

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Table 30-1 (continued)

Toolbar Button	Name	Description
	Play Animation, Play Selected	Cycles through the frames; this button
		becomes a Stop button when an animation is
		playing.
	Next Frame/Key	Advances the time by one frame or selects the
		next key
	Go to End	Sets the time to the final frame
	Key Mode Toggle	Toggles between key and frame modes; with
		Key Mode on, the icon turns light blue and the
		Previous Frame and Next Frame buttons
		change to Previous Key and Next Key.
	Current Frame field	Indicates the current frame; a frame number
		can be typed in this field for more exact
		control than the Time Slider.
	Time Configuration	Opens the Time Configuration dialog box
		where settings like frame rate, time display,
		and animation length can be set

The default scene starts with 100 frames, but this is seldom what you actually need. You can change the number of frames at any time by clicking the Time Configuration button, which is to the right of the frame number field. Clicking this button opens the Time Configuration dialog box, shown in Figure 30-1. You can also access this dialog box by right-clicking any of the Time Control buttons.

Setting frame rate

Within this dialog box, you can set several options, including the Frame Rate. Frame rate provides the connection between the number of frames and time. It is measured in frames per second. The options include standard frame rates such as NTSC (National Television Standards Committee, around 30 frames per second), Film (around 24 frames per second), and PAL (Phase Alternate Line, used by European countries, around 25 frames per second), or you can select Custom and enter your own frame rate.

The Time Display section lets you set how time is displayed on the Time Slider. The options include Frames, SMPTE (Society of Motion Picture Technical Engineers), Frame:Ticks, or MM:SS:Ticks (Minute and Seconds). SMPTE is a standard time measurement used in video and television. A Tick is 1⁄4800 of a second.

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Figure 30-1: The Time Configuration dialog box lets you set the number of frames to include in a scene.

Setting speed and direction

The Playback section sets options for how the animation sequence is played back. The Real Time option skips frames to maintain the specified frame rate. The Active Viewport Only option causes the animation to play only in a single viewport, which speeds up the animation. The Loop option repeats the animation over and over. The Loop option is available only if the Real Time option is disabled. If the Loop option is set, then you can specify the Direction as Forward, Reverse, or Ping-Pong (which repeats playing forward and then reverse). The Speed setting can be 1⁄4, 1⁄2, 1, 2, or 4 times normal.

The Time Configuration dialog box also lets you specify the Start Time, End Time, Length, and Current Time values. These values are all interrelated, so setting the Length and the Start Time, for example, automatically changes the End Time. These values can be changed at any time without destroying any keys. For example, if you have an animation of 500 frames and you set the Start and End Time to 30 and 50, the Time Slider controls only those 21 frames. Keys before or after this time are still available and can be accessed by resetting the Start and End Time values to 0 and 500.

The Re-scale Time button fits all the keys into the active time segment by stretching or shrinking the number of frames between keys. You can use this feature to resize the animation to the number of frames defined by Start and End Time values.

The Key Steps group lets you set which key objects are navigated using key mode. If you select Use Track Bar, key mode moves through only the keys on the Track Bar. If you select the Selected Objects Only option, key mode jumps only to the keys for the currently selected object. You can also filter to move between Position, Rotation, and Scale keys. The Use Current Transform option locates only those keys that are the same as the current selected transform button.

Using Time Tags

To the right of the Prompt Line is a field marked Add Time Tag. Clicking this field pops up a menu with options to Add or Edit a Time Tag. Time Tags can be set for each frame in the scene. Once set, the Time Tags are visible in the Time Tag field whenever that time is selected.

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Working with Keys

It isn’t just a coincidence that the largest button in the entire Max interface has a key on it. Creating and working with keys is how animations are accomplished. Keys define a particular state of an object at a particular time. Animations are created as the object moves or changes between two different key states. Complex animations can be generated with only a handful of keys.

You can create keys in numerous ways, but the easiest is with the Key Controls found on the lower interface bar. These controls are located to the left of the Time Controls. Table 30-2 displays and explains all these controls. Closely related to the Key Controls is the Track Bar, which is located under the Time Slider.

Table 30-2: Key Controls

Toolbar Button	Name	Description
	Set Keys (K)	Creates animation keys in Set Key
		mode
	Toggle AutoKey Mode (N)	Sets keys automatically for the
		selected object when enabled
	Toggle Set Key Mode (')	Sets keys as specified by the key
		filters for the selected object when
		enabled
	Selection Set drop-down list	Specifies a selection set to use for
		the given keys
	Open Filters Dialog box	Contains pop-up options for the
		filtering keys

Max includes two different animation modes: Auto Key (N) and Set Key ('). You can select either of these modes by clicking the respective buttons at the bottom of the interface. When active, the button turns bright red, and the border around the active viewport also turns red to remind you that you are in animate mode. Red also appears around a spinner for any parameters that are animated.

Tip	You can set the Time slider bar to be red as well by adding the following to the 3dsmax.ini file:

[RedSliderWhenAnimating]

Enabled=1

Auto Key mode

With the Auto Key button enabled, every transformation or parameter change creates a key that defines where and how an object should look at that specific frame.

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To create a key, drag the Time Slider to a frame where you want to create a key and then move the selected object or change the parameter, and a key is automatically created. When the first key is created, Max automatically goes back and creates a key for frame 0 that holds the object’s original position or parameter. Upon setting the key, Max then interpolates all the positions and changes between the keys. The key are displayed in the Track Bar.

Each frame can hold several different keys, but only one for each type of transform and each parameter. For example, if you move, rotate, scale, and change the Radius parameter for a sphere object with the Auto Key mode enabled, then a key is created for position, rotation, scaling, and a parameter change.

Set Key mode

The Set Key button (') offers more control over the key creation and sets keys only when you click the Set Key button (K). It also creates keys only for the key types enabled in the Key Filters dialog box. You can open the Key Filters dialog box, shown in Figure 30-2, by clicking the Key Filters button. Available key types include All, Position, Rotation, Scale, IK Parameters, Object Parameters, Custom Attributes, Modifiers, Materials, and Other (which allows keys to be set for manipulator values).

Figure 30-2: Use the Set Key Filters dialog box to specify the types of keys to create.

Tutorial: Rotating a windmill’s blades

The best way to learn is to practice, and there’s no better time to practice than now. For this quick example, you animate a set of blades on a windmill.

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

1.Open the Rotating windmill blades.max file from the Chap 30 directory on the CD-ROM. 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).

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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 30-3 shows frame 50 of this simple animation.

Creating keys with the Time Slider

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 30-4, where you can set Position, Rotation, and Scale keys for the currently selected object. You can use this method only to create transform keys.

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).

Figure 30-3: Frame 50 of this simple windmill animation