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# Action Concepts

The following concepts are used throughout the Action chapters to describe the workflow and user interface.

Scene
  The scene isAction 's representation of 3D world space. It is where objects are placed and animated. World space has three directions: X (left/right), Y (up/down), and Z (in/out).
Object
  An object is any element in a scene. An axis, a camera, a surface, a light, or a model can also be referred to as an object.
Media
  Media consists of a front and matte clip only.
Surface
  A surface is a special type of 3D geometry onto which media is mapped.
Geometric Object (Models)
  A 3D geometric object can be something as simple as a cube, sphere, or cone, or as complex as a character. Although some basic geometric objects are included with Smoke, most geometry is imported from a 3D application such as Maya and 3ds Max®. A model is another way to refer to a geometric object.
Camera
  The camera represents the 'eye' you are using to see the scene. The camera is used to “record” the scene in Action. By default, the camera consists of two objects: the camera eye and the point of interest (the coordinates the camera is 'looking' at).
Axis
  An axis is the element of an object or media that can be manipulated to determine the object's 2D or 3D space, position, and movement.
Schematic
  The schematic is an icon representation of the scene. It shows all the objects in the scene and their relationship with each other.
3D Models and Text
  You can import 3ds Max files, FBX® format files, Wavefront files, Inventor files, and Paint geometry into Action. Also, you can create 3D text with custom beveling.