vtkCellLocator - octree-based spatial search object to quickly locate cells

Super Class: vtkLocator

Description:

vtkCellLocator is a spatial search object to quickly locate cells in 3D. vtkCellLocator uses a uniform-level octree subdivision, where each octant (an octant is also referred to as a bucket) carries an indication of whether it is empty or not, and each leaf octant carries a list of the cells inside of it. (An octant is not empty if it has one or more cells inside of it.) Typical operations are intersection with a line to return candidate cells, or intersection with another vtkCellLocator to return candidate cells.

Caveats:

Many other types of spatial locators have been developed, such as variable depth octrees and kd-trees. These are often more efficient for the operations described here. vtkCellLocator has been designed for subclassing; so these locators can be derived if necessary.

See Also:

vtkLocator vtkPointLocator vtkOBBTree

Methods:

• vtkCellLocator ();
• ~vtkCellLocator ();
• char *GetClassName ();
• void PrintSelf (ostream &os, vtkIndent indent);
• vtkCellLocator *New ();
• void SetNumberOfCellsPerBucket (int );
• int GetNumberOfCellsPerBucket ();
• virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId);
• virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId, int &cellId);
• virtual vtkIdList *GetCells (int bucket);
• void FreeSearchStructure ();
• void BuildLocator ();
• void GenerateRepresentation (int level, vtkPolyData *pd);
• int NumberOfCellsPerBucketint NumberOfOctantsfloat Bounds[6]int NumberOfParentsfloat H[3]int NumberOfDivisionsvtkIdList *Treevoid MarkParents (void *, int , int , int , int , int );
• void GetChildren (int idx, int level, int children[8]);
• int GenerateIndex (int offset, int numDivs, int i, int j, int k, int &idx);
• void GenerateFace (int face, int numDivs, int i, int j, int k, vtkPoints *pts, vtkCellArray *polys);

Detailed Method Descriptions:

• vtkCellLocator *New ();

Construct with automatic computation of divisions, averaging 25 cells per bucket.

• void SetNumberOfCellsPerBucket (int );
• int GetNumberOfCellsPerBucket ();

Specify the average number of cells in each octant.

• virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId);

Return intersection point (if any) of finite line with cells contained in cell locator.

• virtual int IntersectWithLine (float a0[3], float a1[3], float tol, float &t, float x[3], float pcoords[3], int &subId, int &cellId);

Return intersection point (if any) AND the cell which was intersected by the finite line.

• virtual vtkIdList *GetCells (int bucket);

Get the cells in a particular bucket.

• void FreeSearchStructure ();
• void BuildLocator ();
• void GenerateRepresentation (int level, vtkPolyData *pd);

Satisfy vtkLocator abstract interface