The Data Hierarchy Tree

 

The geometric data is organized in a tree and every object belongs to one node of this tree. The simplest and mainly used nodes are of class Scene. They contain a pointer to two further nodes. Usually one of this nodes is a geometric object but it may also be another branch of the tree.

A subclass of Scene is Chain. Scene is mainly used as a binary node whereas nodes of class Chain are used to store a linear sequence of objects as they arise for example when generating multiple copies of an object during reflection operations. Methods on the class Chain assume to find such a linear structure.

A further subclass of Scene is TimeScene. A node in the hierarchy of class TimeScene has additionally a local time and a pointer to a dynamic object. The object of the TimeScene is always a section at the current local time of the dynamic process. This is the simplest way to included dynamic objects into the hierarchy.

Further hierarchy nodes can be instances of class Time-Object, Curve,Surface etc., see 8, for a description of these classes.

The user may also allow his own classes to appear as hierarchy nodes with objects as leaves by supplying a method "follow" for his class defining the nodes' environment.

• Scenes - A Collection of Geometry Objects
  • Methods on Scene
  • Methods for Scene handling
  • Suprop
• Chain
  • Memory Methods on Chain
  • Other Methods on Chain
• TimeScene
  • Memory Methods on TimeScene
  • Other Methods on TimeScene