MACROMEDIA DIRECTOR MX-USING DIRECTOR MX Use Manual page 453

The illustration that follows shows the relationships between the components of a 3D
cast member:
Your movies can use 2D and 3D cast members simultaneously. For example, a product
demonstration movie might consist of a 3D cast member that represents the product and one or
more 2D controls that allow users a virtual tryout of the product.
Models and model resources
Models are the objects that users see within the 3D world. Model resources are elements of 3D
geometry that can be used to draw 3D models. A model is a visible object that makes use of a
model resource and occupies a specific position and orientation with the 3D world. The model
also defines the appearance of the model resource, such as what textures and shaders are used. For
more information, see Chapter 19, "Working with Models and Model Resources," on page 473.
The relationship between a model and a model resource is similar to that between a sprite and a
cast member. Model resource data can be reused because multiple models can use the same model
resource in the same way as cast member data can be reused by multiple sprites. Unlike sprites,
however, models don't appear in and can't be controlled from the Score.
For example, a 3D cast member might contain two model resources. One could be the geometry
for a car body, and the other could be the geometry for a car wheel. In order for a complete car to
appear visibly in the 3D scene, the model resource for the car body would be used once, and the
model resource for the wheel would be used four times—once for each wheel.
All models are located within a parent-child hierarchy. A model can have any number of children
but only one parent. If a model doesn't have another model as a parent, its parent is the group
called "world," which is, for all practical purposes, the 3D cast member.
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