The Inventor scene database consists of information representing one or more 3D scenes. This database, SoDB^{( C++ | Java | .NET )}, can contain several scene graphs, as shown in Figure 3.1, “ An Inventor Database ”. Each scene graph consists of a related set of 3D objects and attributes. In Figure 3.1, “ An Inventor Database ”, for example, the scene graphs might represent a car, a small house, another car, a large house, and a person.

Figure 3.1.  An Inventor Database

You can perform two basic operations, or methods, directly on the scene database. First, you initialize it:

SoDB::init()   
  

This must be the first Inventor call you make. If you use the Inventor Component Library, the database is initialized automatically when you call SoXt::init() (see Chapter 18, Open Inventor Component Library). If you are not using components, but you are using interaction or node kits, or both, call SoInteraction::init(), which initializes the database, interaction, and node kits.

Second, you can read from a file into the scene database, which adds new scene graphs to it:

SoSeparator readAll(SoInput *in)
or
SbBool read(SoInput *in, SoNode *&rootNode) const
  

SoSeparator ReadAll(SoInput in)
or
bool Read(SoInput in, SoNode rootNode)
  

SoSeparator readAll(SoInput in)
or
SoNode read(SoInput in)
  

SbBool read(SoInput *in, SoPath *&path) const
  

bool Read(SoInput in, SoPath path)
  

SoPath readPath(SoInput in)
  

Using the first syntax, Inventor reads all graphs from a file specified by in and returns a pointer to a separator that contains the root nodes of all the scene graphs in the file. Using the second syntax, Inventor reads from a file specified by in and returns a pointer to the resulting root node (rootNode). Using the third syntax, Inventor reads a file specified by in and returns a pointer to the resulting path (path). (See Section 3.6, “Paths”.) If an error occurs, the methods return FALSE. (Also see Chapter 12, Importing data for more information on SoInput^{( C++ | Java | .NET )}.)