NURBS surface shape node. More...

#include <Inventor/nodes/SoNurbsSurface.h>

Inheritance diagram for SoNurbsSurface:

Public Member Functions
	SoNurbsSurface ()
	Creates a NURBS surface node with default settings.
virtual void	GLRender (SoGLRenderAction *action)
	Implements rendering by rendering each primitive generated by subclass.
virtual void	rayPick (SoRayPickAction *action)
	Implements picking along a ray by intersecting the ray with each primitive generated by subclass.
void	sendPrimitive (SoAction , SoPrimitiveVertex )
Static Public Member Functions
static void	initClass ()
	Initializes base node class.
Public Attributes
Fields
SoSFInt32	numUControlPoints
	Number of control points in the U direction.
SoSFInt32	numVControlPoints
	Number of control points in the V direction.
SoSFInt32	numSControlPoints
	Number of control points in S direction.
SoSFInt32	numTControlPoints
	Number of control points in T direction.
SoMFFloat	uKnotVector
	The knot vectors in the U direction.
SoMFFloat	vKnotVector
	The knot vectors in the V direction.
SoMFFloat	sKnotVector
	The knot vectors in the S direction.
SoMFFloat	tKnotVector
	The knot vectors in the T direction.
Protected Member Functions
virtual void	generatePrimitives (SoAction *action)
	Generates triangles representing a surface.
virtual void	computeBBox (SoAction *action, SbBox3f &box, SbVec3f &center)
	Computes bounding box of surface.
	~SoNurbsSurface ()

Detailed Description

This shape node represents a NURBS surface based on the node's knot vectors and on control points constructed from the current coordinates. The current coordinates are used in row-major order (the V direction corresponds to the rows). The number of coordinates used is determined by the numUControlPoints and numVControlPoints fields. The uKnotVector and vKnotVector fields contain floating point arrays of non-decreasing values.

The order of the surface in the U and V directions is defined as the number of knots minus the number of control points in the particular direction. The largest order allowed for a NURBS surface is 8.

The control points of the NURBS surface are transformed by the current cumulative transformation. The surface is drawn with the current light model and drawing style. The coordinates, normals, and texture coordinates of a surface are generated, so you cannot bind explicit normals or texture coordinates to a NURBS surface. The first material in the state is applied to the entire surface.

The surface is trimmed according to the currently defined profile's curves.

When default texture coordinates are applied to a NURBS surface, the edges of the texture square are stretched to fit the surface. The axes of the texture are called S and T; S is horizontal and T is vertical. The axes of the NURBS surface are called U and V; U is horizontal and V is vertical. You can also define texture coordinates explicitly with the S,T location point, the knot vectors, and the current texture coordinates.

The approximation of the surface by polygons is affected by the current complexity value.

File Format/Default

NurbsSurface {
  numUControlPoints 0
  numVControlPoints 0
  numSControlPoints 0
  numTControlPoints 0
  uKnotVector 0
  vKnotVector 0
  sKnotVector 0
  tKnotVector 0
}

Action Behavior

: SoGLRenderAction
Draws the surface based on the current coordinates, material, and so on.

: SoRayPickAction
Picks the surface based on the current coordinates and transformation.

: SoGetBoundingBoxAction
Computes the bounding box that encloses all control points of the surface with the current transformation applied to them. Sets the center to the average of the control points.

: SoCallbackAction
If any triangle callbacks are registered with the action, they will be invoked for each successive triangle approximating the surface.