NAME
vtkImplicitModeller - compute distance from input geometry on structured point dataset
SYNOPSIS
#include "/opt/vtk-c++/graphics/vtkImplicitModeller.h"
class VTK_EXPORT vtkImplicitModeller : public vtkDataSetToStructuredPointsFilter
vtkImplicitModeller();
static vtkImplicitModeller *New() {return new vtkImplicitModeller;};
const char *GetClassName() {return "vtkImplicitModeller";};
void PrintSelf(ostream& os, vtkIndent indent);
float ComputeModelBounds();
int *GetSampleDimensions();
void GetSampleDimensions(int data[3]);
void SetSampleDimensions(int i, int j, int k);
void SetSampleDimensions(int dim[3]);
void SetMaximumDistance(float);
float GetMaximumDistance();
void SetModelBounds(float data[6]);
void SetModelBounds(float *);
float *GetModelBounds();
void GetModelBounds(float data[6]);
void SetModelBounds(float xmin, float xmax, float ymin, float ymax, float zmin, float zmax);
void SetAdjustBounds(int);
int GetAdjustBounds();
void AdjustBoundsOn();
void AdjustBoundsOff();
void SetAdjustDistance(float);
float GetAdjustDistance();
void SetCapping(int);
int GetCapping();
void CappingOn();
void CappingOff();
void SetCapValue(float);
float GetCapValue();
void Update();
void StartAppend();
void Append(vtkDataSet *input);
void EndAppend();
DESCRIPTION
vtkImplicitModeller is a filter that computes the distance from the input geometry to the points of an output structured point set. This distance function can then be "contoured" to generate new, offset surfaces from the original
geometry. An important feature of this object is "capping". If capping is turned on, after the implicit model is created, the values on the boundary of the structured points dataset are set to the cap value. This is used to force closure of the resulting contoured surface. Note, however, that large cap values can generate weird surface normals in those cells adjacent to the boundary of the dataset. Using smaller cap value will reduce this effect.
Another important ivar is MaximumDistance. This controls how far into the volume the distance function is computed from the input geometry. Small values give significant increases in performance. However, there can strange sampling effects at the extreme range of the MaximumDistance.
In order to properly execute and sample the input data, a rectangular region in space must be defined (this is the ivar ModelBounds). If not explicitly defined, the model bounds will be computed. Note that to avoid boundary effects, it is possible to adjust the model bounds (i.e., using the AdjustBounds and AdjustDistance ivars) to strictly contain the sampled data.
This filter has one other unusual capability: it is possible to append data in a sequence of operations to generate a single output. This is useful when you have multiple datasets and want to create a conglomeration of all the data.
SEE ALSO
vtkSampleFunction vtkContourFilter
SUMMARY
int *GetSampleDimensions()
void GetSampleDimensions(int data[3])
Set/Get the i-j-k dimensions on which to sample distance function.
void SetMaximumDistance(float)
Specify distance away from surface of input geometry to sample. Smaller values make large increases in performance.
void SetModelBounds(float data[6])
void SetModelBounds(float *)
Specify the region in space in which to perform the sampling. If not specified, it will be computed automatically.
void SetAdjustBounds(int)
Control how the model bounds are computed. If the ivar AdjustBounds is set, then the bounds specified (or computed automatically) is modified by the fraction given by AdjustDistance. This means that the model bounds is expanded in each of the x-y-z directions.
void SetAdjustDistance(float)
Specify the amount to grow the model bounds (if the ivar AdjustBounds is set). The value is a fraction of the maximum length of the sides of the box specified by the model bounds.
void SetCapping(int)
The outer boundary of the structured point set can be assigned a particular value. This can be used to close or "cap" all surfaces.
void SetCapValue(float)
Specify the capping value to use. The CapValue is also used as an initial distance value at each point in the dataset.
vtkImplicitModeller()
Construct with sample dimensions=(50,50,50), and so that model bounds are automatically computed from the input. Capping is turned on with CapValue equal to a large positive number.
void StartAppend()
Initialize the filter for appending data. You must invoke the StartAppend() method before doing successive Appends(). It's also a good idea to manually specify the model bounds; otherwise the input bounds for the data will be used.
void Append(vtkDataSet *input)
Append a data set to the existing output. To use this function, you'll have to invoke the StartAppend() method before doing successive appends. It's also a good idea to specify the model bounds; otherwise the input model bounds is used. When you've finished appending, use the EndAppend() method.
void EndAppend()
Method completes the append process.
void Update()
Special update methods handles possibility of appending data.
float ComputeModelBounds()
Compute ModelBounds from input geometry.
void SetSampleDimensions(int i, int j, int k)
Set the i-j-k dimensions on which to sample the distance function.