Page 656 - Kitab3DsMax

Part V: Animation and Rendering Basics

Bézier controller
The Bézier controller is the default controller for many parameters. It enables you to interpolate between val-
ues using an adjustable Bézier spline. By dragging its tangent vertex handles, you can control the spline’s cur-
vature. Tangent handles produce a smooth transition when they lie on the same line, or you can create an
angle between them for a sharp point. Figure 22.9 shows the Bézier controller assigned to a Position track.

FIGURE 22.9
The Bézier controller produces smooth animation curves.

The Bézier controller parameters are displayed in the Motion panel under two rollouts: Key Info (Basic) and
Key Info (Advanced).
At the top of the Key Info (Basic) rollout are two arrows and a field that shows the key number. The arrows
let you move between the Previous and Next keys. Each vertex shown in the function curve represents a
key. The Time field displays the frame number where the key is located. The Time Lock button next to the
Time field can be set to prevent the key from being dragged in Track View. The value fields show the values
for the selected track; the number of fields changes depending on the type of track that is selected.
At the bottom of the Key Info (Basic) rollout are two flyout buttons for specifying the In and Out curves for
the key. The arrows to the sides of these buttons move between the various In/Out curve types. The curve
types include Smooth, Linear, Step, Slow, Fast, Custom, and Tangent Copy.

Cross-Ref
Chapter 36, “Working with Function Curves in the Track View,” describes these various In/Out curve types. n
The In and Out values in the Key Info (Advanced) rollout are enabled only when the Custom curve type is
selected. These fields let you define the rate applied to each axis of the curve. The Lock button changes the
two values by equal and opposite amounts. The Normalize Time button averages the positions of all keys.
The Constant Velocity option interpolates the key between its neighboring keys to provide smoother motion.

Linear controller
The Linear controller interpolates between two values to create a straight line by changing its value at a con-
stant rate over time.
The Linear controller doesn’t include any parameters and can be applied to time or values. Figure 22.10
shows the curves from the previous example after the Linear controller is assigned—all curves have been
replaced with straight lines.

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