Indexed NURBS surface shape node. More...

#include <Inventor/nodes/SoIndexedNurbsSurface.h>

Inheritance diagram for SoIndexedNurbsSurface:

Public Member Functions
	SoIndexedNurbsSurface ()
	Creates an indexed 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.
SoMFInt32	coordIndex
	Coordinate indices.
SoMFFloat	uKnotVector
	The knot vectors in the U direction.
SoMFFloat	vKnotVector
	The knot vectors in the V directions.
SoSFInt32	numSControlPoints
	Number of control points in the S direction.
SoSFInt32	numTControlPoints
	Number of control points in the T direction.
SoMFInt32	textureCoordIndex
	Texture coordinate indices.
SoMFFloat	sKnotVector
	The knot vectors in the S direction.
SoMFFloat	tKnotVector
	The knot vectors in the T directions.
Protected Member Functions
virtual void	generatePrimitives (SoAction *action)
	Generates triangles representing surface.
virtual void	computeBBox (SoAction *action, SbBox3f &box, SbVec3f &center)
	Computes bounding box of surface.
	~SoIndexedNurbsSurface ()

Detailed Description

This shape node represents a NURBS surface based on the knot vectors and the control points that you specify. The uKnotVector and vKnotVector fields specify floating-point arrays of values; the values are the coordinates of the knot points in the surface, and you must enter them in non-decreasing order. The numUControlPoints and numVControlPoints fields specify the number of control points the surface will have in the U and V parametric directions, and will use the current coordinates that are indexed from the coordIndex field.

You can get a surface of minimum order (2) in the U or V directions by specifying two more knots than control points in that direction and having at least two control points in that direction. This surface would appear creased in one direction.

You can get a surface of maximum order (8) in the U or V directions by specifying eight more knots than control points in that direction and having at least eight control points in that direction.

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 profiles 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.

File Format/Default

IndexedNurbsSurface {
  numUControlPoints 0
  numVControlPoints 0
  numSControlPoints 0
  numTControlPoints 0
  coordIndex 0
  uKnotVector 0
  vKnotVector 0
  sKnotVector 0
  tKnotVector 0
  textureCoordIndex -1
}

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.