FreeMat
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Section: Visualization Toolkit Common Classes
vtkParametricBoy generates Boy's surface. This is a Model of the projective plane without singularities. It was found by Werner Boy on assignment from David Hilbert.
For further information about this surface, please consult the technical description "Parametric surfaces" in http://www.vtk.org/documents.php in the "VTK Technical Documents" section in the VTk.org web pages.
.SECTION Thanks Andrew Maclean a.mac for creating and contributing the class. lean @cas. edu. au
To create an instance of class vtkParametricBoy, simply invoke its constructor as follows
obj = vtkParametricBoy
The class vtkParametricBoy has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj
is an instance of the vtkParametricBoy class.
string = obj.GetClassName ()
int = obj.IsA (string name)
vtkParametricBoy = obj.NewInstance ()
vtkParametricBoy = obj.SafeDownCast (vtkObject o)
int = obj.GetDimension ()
- Set/Get the scale factor for the z-coordinate. Default = 1/8, giving a nice shape. obj.SetZScale (double )
- Set/Get the scale factor for the z-coordinate. Default = 1/8, giving a nice shape. double = obj.GetZScale ()
- Set/Get the scale factor for the z-coordinate. Default = 1/8, giving a nice shape. obj.Evaluate (double uvw[3], double Pt[3], double Duvw[9])
- Boy's surface.
This function performs the mapping , returning it as Pt. It also returns the partial derivatives Du and Dv.
. Then the normal is
.
double = obj.EvaluateScalar (double uvw[3], double Pt[3], double Duvw[9])
- Calculate a user defined scalar using one or all of uvw, Pt, Duvw.
uvw are the parameters with Pt being the the cartesian point, Duvw are the derivatives of this point with respect to u, v and w. Pt, Duvw are obtained from Evaluate().
This function is only called if the ScalarMode has the value vtkParametricFunctionSource::SCALAR_FUNCTION_DEFINED
If the user does not need to calculate a scalar, then the instantiated function should return zero.