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vtkQuadricDecimation Class Reference

reduce the number of triangles in a mesh More...

#include <vtkQuadricDecimation.h>

Inherits vtkPolyDataAlgorithm.

Collaboration diagram for vtkQuadricDecimation:
[legend]

Classes

struct  ErrorQuadric
 

Public Types

typedef vtkPolyDataAlgorithm Superclass
 

Public Member Functions

virtual int IsA (const char *type)
 
vtkQuadricDecimationNewInstance () const
 
void PrintSelf (ostream &os, vtkIndent indent)
 
virtual void SetTargetReduction (double)
 
virtual double GetTargetReduction ()
 
virtual void SetAttributeErrorMetric (int)
 
virtual int GetAttributeErrorMetric ()
 
virtual void AttributeErrorMetricOn ()
 
virtual void AttributeErrorMetricOff ()
 
virtual void SetScalarsAttribute (int)
 
virtual int GetScalarsAttribute ()
 
virtual void ScalarsAttributeOn ()
 
virtual void ScalarsAttributeOff ()
 
virtual void SetVectorsAttribute (int)
 
virtual int GetVectorsAttribute ()
 
virtual void VectorsAttributeOn ()
 
virtual void VectorsAttributeOff ()
 
virtual void SetNormalsAttribute (int)
 
virtual int GetNormalsAttribute ()
 
virtual void NormalsAttributeOn ()
 
virtual void NormalsAttributeOff ()
 
virtual void SetTCoordsAttribute (int)
 
virtual int GetTCoordsAttribute ()
 
virtual void TCoordsAttributeOn ()
 
virtual void TCoordsAttributeOff ()
 
virtual void SetTensorsAttribute (int)
 
virtual int GetTensorsAttribute ()
 
virtual void TensorsAttributeOn ()
 
virtual void TensorsAttributeOff ()
 
virtual void SetScalarsWeight (double)
 
virtual void SetVectorsWeight (double)
 
virtual void SetNormalsWeight (double)
 
virtual void SetTCoordsWeight (double)
 
virtual void SetTensorsWeight (double)
 
virtual double GetScalarsWeight ()
 
virtual double GetVectorsWeight ()
 
virtual double GetNormalsWeight ()
 
virtual double GetTCoordsWeight ()
 
virtual double GetTensorsWeight ()
 
virtual double GetActualReduction ()
 

Static Public Member Functions

static int IsTypeOf (const char *type)
 
static vtkQuadricDecimationSafeDownCast (vtkObjectBase *o)
 
static vtkQuadricDecimationNew ()
 

Protected Member Functions

virtual vtkObjectBase * NewInstanceInternal () const
 
 vtkQuadricDecimation ()
 
 ~vtkQuadricDecimation ()
 
int RequestData (vtkInformation *, vtkInformationVector **, vtkInformationVector *)
 
int CollapseEdge (vtkIdType pt0Id, vtkIdType pt1Id)
 
void InitializeQuadrics (vtkIdType numPts)
 
void AddBoundaryConstraints (void)
 
void ComputeQuadric (vtkIdType pointId)
 
void AddQuadric (vtkIdType oldPtId, vtkIdType newPtId)
 
void FindAffectedEdges (vtkIdType p1Id, vtkIdType p2Id, vtkIdList *edges)
 
vtkIdType GetEdgeCellId (vtkIdType p1Id, vtkIdType p2Id)
 
int IsGoodPlacement (vtkIdType pt0Id, vtkIdType pt1Id, const double *x)
 
int TrianglePlaneCheck (const double t0[3], const double t1[3], const double t2[3], const double *x)
 
void ComputeNumberOfComponents (void)
 
void UpdateEdgeData (vtkIdType ptoId, vtkIdType pt1Id)
 
void GetAttributeComponents ()
 
double ComputeCost (vtkIdType edgeId, double *x)
 
double ComputeCost2 (vtkIdType edgeId, double *x)
 
void SetPointAttributeArray (vtkIdType ptId, const double *x)
 
void GetPointAttributeArray (vtkIdType ptId, double *x)
 

Protected Attributes

double TargetReduction
 
double ActualReduction
 
int AttributeErrorMetric
 
int ScalarsAttribute
 
int VectorsAttribute
 
int NormalsAttribute
 
int TCoordsAttribute
 
int TensorsAttribute
 
double ScalarsWeight
 
double VectorsWeight
 
double NormalsWeight
 
double TCoordsWeight
 
double TensorsWeight
 
int NumberOfEdgeCollapses
 
vtkEdgeTable * Edges
 
vtkIdList * EndPoint1List
 
vtkIdList * EndPoint2List
 
vtkPriorityQueue * EdgeCosts
 
vtkDoubleArray * TargetPoints
 
int NumberOfComponents
 
vtkPolyData * Mesh
 
ErrorQuadricErrorQuadrics
 
int AttributeComponents [6]
 
double AttributeScale [6]
 
vtkIdList * CollapseCellIds
 
double * TempX
 
double * TempQuad
 
double * TempB
 
double ** TempA
 
double * TempData
 

Detailed Description

reduce the number of triangles in a mesh

vtkQuadricDecimation is a filter to reduce the number of triangles in a triangle mesh, forming a good approximation to the original geometry. The input to vtkQuadricDecimation is a vtkPolyData object, and only triangles are treated. If you desire to decimate polygonal meshes, first triangulate the polygons with vtkTriangleFilter.

The algorithm is based on repeated edge collapses until the requested mesh reduction is achieved. Edges are placed in a priority queue based on the "cost" to delete the edge. The cost is an approximate measure of error (distance to the original surface)–described by the so-called quadric error measure. The quadric error measure is associated with each vertex of the mesh and represents a matrix of planes incident on that vertex. The distance of the planes to the vertex is the error in the position of the vertex (originally the vertex error iz zero). As edges are deleted, the quadric error measure associated with the two end points of the edge are summed (this combines the plane equations) and an optimal collapse point can be computed. Edges connected to the collapse point are then reinserted into the queue after computing the new cost to delete them. The process continues until the desired reduction level is reached or topological constraints prevent further reduction. Note that this basic algorithm can be extended to higher dimensions by taking into account variation in attributes (i.e., scalars, vectors, and so on).

This paper is based on the work of Garland and Heckbert who first presented the quadric error measure at Siggraph '97 "Surface Simplification Using Quadric Error Metrics". For details of the algorithm Michael Garland's Ph.D. thesis is also recommended. Hughues Hoppe's Vis '99 paper, "New Quadric Metric for Simplifying Meshes with Appearance Attributes" is also a good take on the subject especially as it pertains to the error metric applied to attributes.

Thanks:
Thanks to Bradley Lowekamp of the National Library of Medicine/NIH for contributing this class.
Tests:
vtkQuadricDecimation (Tests)

Definition at line 70 of file vtkQuadricDecimation.h.

Member Typedef Documentation

typedef vtkPolyDataAlgorithm vtkQuadricDecimation::Superclass

Definition at line 73 of file vtkQuadricDecimation.h.

Constructor & Destructor Documentation

vtkQuadricDecimation::vtkQuadricDecimation ( )
protected
vtkQuadricDecimation::~vtkQuadricDecimation ( )
protected

Member Function Documentation

static int vtkQuadricDecimation::IsTypeOf ( const char *  type)
static
virtual int vtkQuadricDecimation::IsA ( const char *  type)
virtual
static vtkQuadricDecimation* vtkQuadricDecimation::SafeDownCast ( vtkObjectBase *  o)
static
virtual vtkObjectBase* vtkQuadricDecimation::NewInstanceInternal ( ) const
protectedvirtual
vtkQuadricDecimation* vtkQuadricDecimation::NewInstance ( ) const
void vtkQuadricDecimation::PrintSelf ( ostream &  os,
vtkIndent  indent 
)
static vtkQuadricDecimation* vtkQuadricDecimation::New ( )
static
virtual void vtkQuadricDecimation::SetTargetReduction ( double  )
virtual

Set/Get the desired reduction (expressed as a fraction of the original number of triangles). The actual reduction may be less depending on triangulation and topological constraints.

virtual double vtkQuadricDecimation::GetTargetReduction ( )
virtual

Set/Get the desired reduction (expressed as a fraction of the original number of triangles). The actual reduction may be less depending on triangulation and topological constraints.

virtual void vtkQuadricDecimation::SetAttributeErrorMetric ( int  )
virtual

Decide whether to include data attributes in the error metric. If off, then only geometric error is used to control the decimation. By default the attribute errors are off.

virtual int vtkQuadricDecimation::GetAttributeErrorMetric ( )
virtual

Decide whether to include data attributes in the error metric. If off, then only geometric error is used to control the decimation. By default the attribute errors are off.

virtual void vtkQuadricDecimation::AttributeErrorMetricOn ( )
virtual

Decide whether to include data attributes in the error metric. If off, then only geometric error is used to control the decimation. By default the attribute errors are off.

virtual void vtkQuadricDecimation::AttributeErrorMetricOff ( )
virtual

Decide whether to include data attributes in the error metric. If off, then only geometric error is used to control the decimation. By default the attribute errors are off.

virtual void vtkQuadricDecimation::SetScalarsAttribute ( int  )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual int vtkQuadricDecimation::GetScalarsAttribute ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::ScalarsAttributeOn ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::ScalarsAttributeOff ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::SetVectorsAttribute ( int  )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual int vtkQuadricDecimation::GetVectorsAttribute ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::VectorsAttributeOn ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::VectorsAttributeOff ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::SetNormalsAttribute ( int  )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual int vtkQuadricDecimation::GetNormalsAttribute ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::NormalsAttributeOn ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::NormalsAttributeOff ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::SetTCoordsAttribute ( int  )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual int vtkQuadricDecimation::GetTCoordsAttribute ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::TCoordsAttributeOn ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::TCoordsAttributeOff ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::SetTensorsAttribute ( int  )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual int vtkQuadricDecimation::GetTensorsAttribute ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::TensorsAttributeOn ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::TensorsAttributeOff ( )
virtual

If attribute errors are to be included in the metric (i.e., AttributeErrorMetric is on), then the following flags control which attributes are to be included in the error calculation. By default all of these are on.

virtual void vtkQuadricDecimation::SetScalarsWeight ( double  )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual void vtkQuadricDecimation::SetVectorsWeight ( double  )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual void vtkQuadricDecimation::SetNormalsWeight ( double  )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual void vtkQuadricDecimation::SetTCoordsWeight ( double  )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual void vtkQuadricDecimation::SetTensorsWeight ( double  )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetScalarsWeight ( )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetVectorsWeight ( )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetNormalsWeight ( )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetTCoordsWeight ( )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetTensorsWeight ( )
virtual

Set/Get the scaling weight contribution of the attribute. These values are used to weight the contribution of the attributes towards the error metric.

virtual double vtkQuadricDecimation::GetActualReduction ( )
virtual

Get the actual reduction. This value is only valid after the filter has executed.

int vtkQuadricDecimation::RequestData ( vtkInformation *  ,
vtkInformationVector **  ,
vtkInformationVector *   
)
protected
int vtkQuadricDecimation::CollapseEdge ( vtkIdType  pt0Id,
vtkIdType  pt1Id 
)
protected

Do the dirty work of eliminating the edge; return the number of triangles deleted.

void vtkQuadricDecimation::InitializeQuadrics ( vtkIdType  numPts)
protected

Compute quadric for all vertices

void vtkQuadricDecimation::AddBoundaryConstraints ( void  )
protected

Free boundary edges are weighted

void vtkQuadricDecimation::ComputeQuadric ( vtkIdType  pointId)
protected

Compute quadric for this vertex.

void vtkQuadricDecimation::AddQuadric ( vtkIdType  oldPtId,
vtkIdType  newPtId 
)
protected

Add the quadrics for these 2 points since the edge between them has been collapsed.

double vtkQuadricDecimation::ComputeCost ( vtkIdType  edgeId,
double *  x 
)
protected

Compute cost for contracting this edge and the point that gives us this cost.

double vtkQuadricDecimation::ComputeCost2 ( vtkIdType  edgeId,
double *  x 
)
protected

Compute cost for contracting this edge and the point that gives us this cost.

void vtkQuadricDecimation::FindAffectedEdges ( vtkIdType  p1Id,
vtkIdType  p2Id,
vtkIdList *  edges 
)
protected

Find all edges that will have an endpoint change ids because of an edge collapse. p1Id and p2Id are the endpoints of the edge. p2Id is the pointId being removed.

vtkIdType vtkQuadricDecimation::GetEdgeCellId ( vtkIdType  p1Id,
vtkIdType  p2Id 
)
protected

Find a cell that uses this edge.

int vtkQuadricDecimation::IsGoodPlacement ( vtkIdType  pt0Id,
vtkIdType  pt1Id,
const double *  x 
)
protected
int vtkQuadricDecimation::TrianglePlaneCheck ( const double  t0[3],
const double  t1[3],
const double  t2[3],
const double *  x 
)
protected
void vtkQuadricDecimation::ComputeNumberOfComponents ( void  )
protected
void vtkQuadricDecimation::UpdateEdgeData ( vtkIdType  ptoId,
vtkIdType  pt1Id 
)
protected
void vtkQuadricDecimation::SetPointAttributeArray ( vtkIdType  ptId,
const double *  x 
)
protected

Helper function to set and get the point and it's attributes as an array

void vtkQuadricDecimation::GetPointAttributeArray ( vtkIdType  ptId,
double *  x 
)
protected

Helper function to set and get the point and it's attributes as an array

void vtkQuadricDecimation::GetAttributeComponents ( )
protected

Find out how many components there are for each attribute for this poly data.

Member Data Documentation

double vtkQuadricDecimation::TargetReduction
protected

Definition at line 193 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::ActualReduction
protected

Definition at line 194 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::AttributeErrorMetric
protected

Definition at line 195 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::ScalarsAttribute
protected

Definition at line 197 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::VectorsAttribute
protected

Definition at line 198 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::NormalsAttribute
protected

Definition at line 199 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::TCoordsAttribute
protected

Definition at line 200 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::TensorsAttribute
protected

Definition at line 201 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::ScalarsWeight
protected

Definition at line 203 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::VectorsWeight
protected

Definition at line 204 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::NormalsWeight
protected

Definition at line 205 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::TCoordsWeight
protected

Definition at line 206 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::TensorsWeight
protected

Definition at line 207 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::NumberOfEdgeCollapses
protected

Definition at line 209 of file vtkQuadricDecimation.h.

vtkEdgeTable* vtkQuadricDecimation::Edges
protected

Definition at line 210 of file vtkQuadricDecimation.h.

vtkIdList* vtkQuadricDecimation::EndPoint1List
protected

Definition at line 211 of file vtkQuadricDecimation.h.

vtkIdList* vtkQuadricDecimation::EndPoint2List
protected

Definition at line 212 of file vtkQuadricDecimation.h.

vtkPriorityQueue* vtkQuadricDecimation::EdgeCosts
protected

Definition at line 213 of file vtkQuadricDecimation.h.

vtkDoubleArray* vtkQuadricDecimation::TargetPoints
protected

Definition at line 214 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::NumberOfComponents
protected

Definition at line 215 of file vtkQuadricDecimation.h.

vtkPolyData* vtkQuadricDecimation::Mesh
protected

Definition at line 216 of file vtkQuadricDecimation.h.

ErrorQuadric* vtkQuadricDecimation::ErrorQuadrics
protected

Definition at line 225 of file vtkQuadricDecimation.h.

int vtkQuadricDecimation::AttributeComponents[6]
protected

Definition at line 226 of file vtkQuadricDecimation.h.

double vtkQuadricDecimation::AttributeScale[6]
protected

Definition at line 227 of file vtkQuadricDecimation.h.

vtkIdList* vtkQuadricDecimation::CollapseCellIds
protected

Definition at line 230 of file vtkQuadricDecimation.h.

double* vtkQuadricDecimation::TempX
protected

Definition at line 231 of file vtkQuadricDecimation.h.

double* vtkQuadricDecimation::TempQuad
protected

Definition at line 232 of file vtkQuadricDecimation.h.

double* vtkQuadricDecimation::TempB
protected

Definition at line 233 of file vtkQuadricDecimation.h.

double** vtkQuadricDecimation::TempA
protected

Definition at line 234 of file vtkQuadricDecimation.h.

double* vtkQuadricDecimation::TempData
protected

Definition at line 235 of file vtkQuadricDecimation.h.


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