Biomatic Memory Models
A scene graph is a general data structure commonly used by vector-based graphics editing applications and modern computer games, which arranges the logical and often (but not necessarily) spatial representation of a graphical scene. Examples of such programs include Acrobat 3D, Adobe Illustrator, AutoCAD, CorelDRAW, OpenSceneGraph, OpenSG, VRML97, X3D, Hoops and Open Inventor.
A scene graph is a collection of nodes in a graph or tree structure. A tree node (in the overall tree structure of the scene graph) may have many children but often only a single parent, with the effect of a parent applied to all its child nodes; an operation performed on a group automatically propagates its effect to all of its members. In many programs, associating a geometrical transformation matrix (see also transformation and matrix) at each group level and concatenating such matrices together is an efficient and natural way to process such operations. A common feature, for instance, is the ability to group related shapes/objects into a compound object that can then be moved, transformed, selected, etc. as easily as a single object.
It also happens that in some scene graphs, a node can have a relation to any node including itself, or at least an extension that refers to another node (for instance Pixar's PhotoRealistic RenderMan because of its usage of Reyes rendering algorithm, or Adobe Systems's Acrobat 3D for advanced interactive manipulation).
The term scene graph is sometimes confused with Canvas (GUI), since some canvas implementations include scene graph functionality.
Digital computers store their memory in a collection of zeros and ones. Molecular memory can contain zeros and ones as well as memories stored in vibrational patterns such as rotations of covalent bonds. One example is the vibrations of histone proteins and control of DNA expression patterns. As the histones transition form state to state different sequences of proteins are produced to yield a given result in the cell.