The 3D World - MACROMEDIA DIRECTOR MX 2004-USING DIRECTOR Use Manual

The 3D world

This section provides a brief overview of the contents of 3D cast members. For more detailed
information, see
Each 3D cast member contains a complete 3D world. It can contain models (the objects that
viewers see within the world) that are illuminated by lights and viewed by cameras. A sprite of a
3D cast member represents a specific camera's view into the world. Imagine that the 3D cast
member is a room filled with furniture with cameras pointing in from several windows. A given
sprite using that cast member will display the view from one of those cameras, but the room
itself—the 3D cast member—remains the same regardless of which view is used.
The key difference between 3D cast members and other cast members is that the models within
the 3D world are not independent entities—they're not sprites. They are integral parts of the 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 within 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
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.
Each 3D cast member contains a group object called world, which may contain a tree-like parent-
child hierarchy of nodes, such as models, groups, lights, and cameras. Each node may have one
parent and any number of children. Nodes that have world as an ancestor are rendered. A cast
member may also contain nodes that do not have world as an ancestor, such as nodes with a
property set to VOID; such nodes are not rendered.
parent
The primary benefit of these parent-child relationships is that they make it easier to move
complex models around in the 3D world and to have the component parts of those models move
together in the proper way. In the example of the car previously described, if the wheels of the car
are defined as children of the car model, then moving the car will cause the wheels to be moved
with the car in the expected manner. If no parent-child relationship is defined between the car
and the wheels, moving only the car will cause the wheels to be left behind in their original
position in the world.
"About the 3D cast member" on page
Chapter 16, "Working with Models and Model Resources," on page
315.
335.
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