Scene Basic Types

This section discusses Inventor's Sb classes, a set of basic types that are used in many Inventor objects. Inventor includes useful methods for converting between different types and performing specific 3D operations on them.

Inventor defines the following types:

SbBool	Boolean value (TRUE or FALSE)
SbBox nx	2D or 3D box that has planes parallel to the major axes and is specified by two points on a diagonal (includes SbBox3f, SbBox2f, SbBox2s); n is the number of values in the type (2 or 3), and x is the value type (f for float, s for short)
SbColor	RGB (red/green/blue) color value with conversion routines to other color spaces
SbCylinder	cylinder
SbLine	directed 3D line
SbMatrix	4×4 matrix
SbName	character string stored in a special table for fast and easy comparison, typically for identifiers
SbPList	list of generic (**void* **) pointers
SbPlane	oriented 3D plane
SbRotation	representation of a 3D rotation about an arbitrary axis
SbSphere	sphere
SbString	“smart” character strings that have many convenience methods for easy string manipulation
SbTime	representation of time—in seconds; seconds and microseconds; or using the timeval structure
SbVec nx	2D or 3D vector, used to represent points or directions (includes SbVec2f, SbVec3f, SbVec2s); n is the number of values in the type (2, 3, or 4), and x is the value type (f for float; s for short)
SbViewportRegion	active viewport region within a display window
SbViewVolume	view volume (for example, see SoCamera 's getViewVolume() method in the Open Inventor C++ Reference Manual)

Methods

Each Sb class has useful operators associated with it. For example, you can negate a variable of type SbVec3f, multiply it by a matrix, or normalize it to unit length. The following code creates a unit-length vector, based on the specified direction:

C++ :

SbVec3f v( 1.0, 2.0, 3.0 ); // declares and initializes the vector
v.normalize();              // normalizes the vector to unit length

C# :

SbVec3f v = new SbVec3f( 1.0f, 2.0f, 3.0f ); // declares and initializes the vector
v.Normalize();                               // normalizes the vector to unit length

Java :

SbVec3f v = new SbVec3f( 1.0f, 2.0f, 3.0f ); // declares and initializes the vector
v.normalize();                               // normalizes the vector to unit length

Similarly, SbMatrix has useful methods including multVecMatrix(), which multiplies a row vector by the matrix and returns the result, and rotate(), which sets the matrix to rotate by a given amount. See the Open Inventor C++ Reference Manual for a complete description of the available methods for each Sb class.

Types versus Fields

Nodes and Groups contains a complete discussion of fields, which are the structures that store parameters for nodes. A field contains a value of a certain type. Fields are always contained within Inventor nodes. Many fields contain a corresponding Sb type. For example:

• A field of type SoSFVec3f contains an SbVec3f
• A field of type SoSFRotation contains an SbRotation
• A field of type SoSFName contains an SbName