NAME
vtkRotationalExtrusionFilter - sweep polygonal data creating "skirt" from free edges and lines, and lines from vertices
SYNOPSIS
#include "/opt/vtk-c++/graphics/vtkRotationalExtrusionFilter.h"
class VTK_EXPORT vtkRotationalExtrusionFilter : public vtkPolyDataToPolyDataFilter
vtkRotationalExtrusionFilter();
static vtkRotationalExtrusionFilter *New() {return new vtkRotationalExtrusionFilter;};
const char *GetClassName() {return "vtkRotationalExtrusionFilter";};
void PrintSelf(ostream& os, vtkIndent indent);
void SetResolution(int);
int GetResolution();
void SetCapping(int);
int GetCapping();
void CappingOn();
void CappingOff();
void SetAngle(float);
float GetAngle();
void SetTranslation(float);
float GetTranslation();
void SetDeltaRadius(float);
float GetDeltaRadius();
DESCRIPTION
vtkRotationalExtrusionFilter is a modelling filter. It takes polygonal data as input and generates polygonal data on output. The input dataset is swept around the z-axis to create new polygonal primitives. These primitives form a "skirt" or swept surface. For example, sweeping a line results in a cylindrical shell, and sweeping a circle creates a torus.
There are a number of control parameters for this filter. You can control whether the sweep of a 2D object (i.e., polygon or triangle strip) is capped with the generating geometry via the "Capping" instance variable. Also, you can control the angle of rotation, and whether translation along the z-axis is performed along with the rotation. (Translation is useful for creating "springs".) You also can adjust the radius of the generating geometry using the "DeltaRotation" instance variable.
The skirt is generated by locating certain topological features. Free edges (edges of polygons or triangle strips only used by one polygon or triangle strips) generate surfaces. This is true also of lines or polylines. Vertices generate lines.
This filter can be used to model axisymmetric objects like cylinders, bottles, and wine glasses; or translational/rotational symmetric objects like springs or corkscrews.
CAVEATS
If the object sweeps 360 degrees, radius does not vary, and the object does not translate, capping is not performed. This is because the cap is unnecessary.
Some polygonal objects have no free edges (e.g., sphere). When swept, this will result in two separate surfaces if capping is on, or no surface if capping is off.
SEE ALSO
vtkLinearExtrusionFilter
SUMMARY
void SetResolution(int)
Set/Get resolution of sweep operation. Resolution controls the number of intermediate node points.
void SetCapping(int)
Turn on/off the capping of the skirt.
void SetAngle(float)
Set/Get angle of rotation.
void SetTranslation(float)
Set/Get total amount of translation along the z-axis.
void SetDeltaRadius(float)
Set/Get change in radius during sweep process.
vtkRotationalExtrusionFilter()
Create object with capping on, angle of 360 degrees, resolution = 12, and no translation along z-axis. vector (0,0,1), and point (0,0,0).