Understanding Controllers

Controllers are plug-ins that handle all of the animation tasks in gmax, including:

• Storing animation key values.

• Storing procedural animation settings.

• Interpolating between animation key values.

Most parameters don't receive a controller until you animate them. As soon as you change a parameter with the Animate button on, or click in its track using Track View Add Keys, a default controller is assigned to the parameter.

Accessing Controllers

There are two places where you work directly with controllers:

• Track View: Controllers are indicated in the Hierarchy list by the green arrow icon. Using Track View you can view and work with the controllers for all objects and all parameters. See Track View.

• Motion panel: Contains special tools for working with transform controllers. The Motion panel contains many of the same controller functions as Track View, plus controls necessary for working with special controllers such as the IK Solvers. Using the Motion panel you can view and work with the transform controllers of a single selected object. See Motion Panel.

Categories of Controllers

There are two main categories of controllers. These categories are easy to identify when looking at the Track View Hierarchy list.

Single-Parameter Controllers: Control animation values of a single gmax parameter. Regardless of whether the parameter has a single component, such as the number of sides of a cylinder, or multiple components, such as the RGB values of a color, the controller is handling a single parameter.

Compound Controllers: Combine or manage multiple controllers. Compound controllers include high-level Transform controllers, such as PRS, the Euler XYZ Rotation controller, the Transform Script controller, and the List controller.

A compound controller appears in the Hierarchy list as a controller icon with subordinate-level branches of other controllers.

Controllers and Constraints

In addition to controllers, the software provides the capability of animating using constraints. Many of the items are located in the Animation > Constraint menu. The controllers that are also constraints include the following: Attachment, Surface, Path, Link, and Look-At, Position and Orientation.

When you assign a Controller in the Motion panel or in Track View, you will see these constraints appearing in the list of available controllers. You can assign them just the same as the other controllers, but they are also assignable from the Animation > Constraints submenu. For more information, see Animation Constraints.

Viewing Controller Types

You can view the controller type assigned to a parameter in both Track View and in the Motion panel. Before you can view the controller types in Track View, you must do two things:

1. Select Controller Types display on the Track View Filters dialog.

2. Assign controllers to parameters.

The Parameters mode of the Motion panel always displays the transform controller types for the selected object.

Reading Controller Types

You can tell a lot about how a parameter is animated by looking at the controller type.

Parameter Name: Is always visible and is always to the right of the controller icon. It tells you what is animated.

Interpolation Type: Usually follows the parameter name. It tells how animation values are calculated. The label Diffuse: Bezier Color indicates a Diffuse color parameter using Bezier interpolation with Color data.

Data Type: Usually follows the interpolation type. It tells what type of data is used. The label Height: Linear Float indicates a Height parameter using Linear interpolation with a floating point value.