About Group Objects

A group object (or, more briefly, a group ) is a type of QuickDraw 3D object that you can use to collect objects together into lists or hierarchical models. A group object is an instance of the TQ3GroupObject class. As you've seen, the TQ3GroupObject class is a subclass of the TQ3ShapeObject , which is itself a subclass of the TQ3SharedObject class. As a result, a group object is associated with a reference count, which is incremented or decremented whenever you create or dispose of an instance of that group.

The objects you put into in a group are not copied into the group. Instead, references to the objects are maintained in the group. Accordingly, you can include in a group only shared objects (that is, the types of objects that have reference counts). A group can contain other groups, because groups are shared objects. QuickDraw 3D provides functions that you can use to add objects to a group or remove objects from a group. It also provides functions that you can use to access objects by their position in the group.

Group Types

Group Positions

Group State Flags

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© 1997 Apple Computer, Inc.

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