SoNurbsProperty Class Reference
[Properties]

Node that defines additional properties for rendering a NURBS surface. More...

#include <Inventor/nodes/SoNurbsProperty.h>

Inheritance diagram for SoNurbsProperty:

Public Types
enum	DrawStyle { NORMAL = 0x01, BOUNDARIES_AND_TRIM_CURVES = 0x02, CENTRAL_ISO_PARAM_CURVES = 0x04 }
enum	TessellationType { CONSTANT, ADAPTIVE }
Public Member Functions
virtual SoType	getTypeId () const
	SoNurbsProperty ()
Static Public Member Functions
static SoType	getClassTypeId ()
Public Attributes
SoSFBitMask	drawStyle
SoSFInt32	numSamplePoints
SoSFColor	color
SoSFUShort	isoParamCurvesPattern
SoSFEnum	tessellationType
SoSFFloat	tessellationDistance
SoSFFloat	tessellationAngle

Detailed Description

Node that defines additional properties for rendering a NURBS surface.

This node defines an additional set of properties used by SoNurbsSurface when rendering NURBS surfaces.

For a large NURBS surface, it is sometimes more effective to display two central isoparametric curves rather than facet boundaries (as in wireframe mode) because the latter may provide an overly complicated view of the surface.

This node allows you to specify the NURBS draw style; the color of the trim curves, boundaries and isoparametric curves; the line pattern of the isoparametric curves; the number of sample points between trim curves control points; the type of tessellation; angle and distance for adaptive tessellation.

The NURBS draw style is a bitmask specifying which combination of the following representations to use for displaying the NURBS: normal display, trim curves and boundaries, and/or central isoparametric curves.

Turning off the normal NURBS surface display, and turning on the display of trim curves, boundaries and isoparametric curves can dramatically speed up rendering of large models.

When in ADAPTIVE tessellation mode, regions with a low curvature will be less tessellated than regions with a high curvature.

FILE FORMAT/DEFAULT

drawStyle	NORMAL
numSamplePoints	-1
color	1 1 1
isoParamCurvesPattern	0xFFFF
tessellationType	CONSTANT
tessellationDistance	0.01
tessellationAngle	0.35

ACTION BEHAVIOR

SoNurbsPropertyElement

Member Enumeration Documentation

enum SoNurbsProperty::DrawStyle

Draw style.

Enumerator:

NORMAL	Draw the NURBS surface normally.
BOUNDARIES_AND_TRIM_CURVES	Draw the boundaries of the surface and trim curves.
CENTRAL_ISO_PARAM_CURVES	Draw two isoparametric curves in the middle of the surface (one for U = 0.5 and one for V=0.5).

enum SoNurbsProperty::TessellationType

Tesselation type.

Enumerator:

CONSTANT

The tessellation step size is constant and the same for both the U and V axes.

The tessellation step size depends on SoComplexity::value.

ADAPTIVE

The tessellation depends on the curvature of the geometry.

Regions with a low curvature will be less tessellated than regions with a high curvature.

Constructor & Destructor Documentation

SoNurbsProperty::SoNurbsProperty ( )

Constructor.

Member Function Documentation

static SoType SoNurbsProperty::getClassTypeId ( ) [static]

Returns the type identifier for this class.

Reimplemented from SoNode.

virtual SoType SoNurbsProperty::getTypeId ( ) const [virtual]

Returns the type identifier for this specific instance.

Reimplemented from SoNode.

Member Data Documentation

SoSFColor SoNurbsProperty::color

Contains the color used to render trim curves and isoparametric curves.

SoSFBitMask SoNurbsProperty::drawStyle

Indicates which part of the NURBS surface to render.

Use enum DrawStyle. Default is NORMAL.

SoSFUShort SoNurbsProperty::isoParamCurvesPattern

Sets a specific line pattern for isoparametric curves.

SoSFInt32 SoNurbsProperty::numSamplePoints

numSamplePoints is used during trim curve tessellation.

It specifies the exact number of points to generate between two trim curve control points. If set to -1 (the default), the number of points generated is computed from the SoComplexity node. Setting this field to a small value (less than 3) can reduce the number of triangles generated by the tessellation and thus increase the drawing performance of trimmed NURBS surfaces.

SoSFFloat SoNurbsProperty::tessellationAngle

Used when tessellationType is set to ADAPTIVE.

Specifies the maximum angle (in radians) between the normals of two adjacent tessellated faces. Decreasing this value adds more tessellation points on flat parts of the surface. Default value is 0.35

NOTE: field available since Open Inventor 6.0

SoSFFloat SoNurbsProperty::tessellationDistance

Used when tessellationType is set to ADAPTIVE.

The maximum tessellation step size (curvilinear distance) is this fraction of the diagonal of the bounding box of the surface or the group of surfaces (SoNurbsGroup). Increasing this value make the tessellation more dependent on tessellationAngle. Default value is 0.01. That is, the distance must not be more than 1% of the diagonal of the bounding box.

NOTE: field available since Open Inventor 6.0

SoSFEnum SoNurbsProperty::tessellationType

Specifies the tessellation type.

* Use enum TessellationType. Default is CONSTANT.

NOTE: field available since Open Inventor 6.0

The documentation for this class was generated from the following file: