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Usage
vtkImplicitFunction specifies an abstract interface for
implicit functions. Implicit functions are real valued
functions defined in 3D space, w = F(x,y,z). Two primitive
operations are required: the ability to evaluate the
function, and the function gradient at a given point. The
implicit function divides space into three regions: on the
surface (F(x,y,z)=w), outside of the surface (F(x,y,z)>c),
and inside the surface (F(x,y,z)<c). (When c is zero,
positive values are outside, negative values are inside, and
zero is on the surface. Note also that the function gradient
points from inside to outside.)
Implicit functions are very powerful. It is possible to
represent almost any type of geometry with the level sets w
= const, especially if you use boolean combinations of
implicit functions (see vtkImplicitBoolean).
vtkImplicitFunction provides a mechanism to transform the
implicit function(s) via a vtkAbstractTransform. This
capability can be used to translate, orient, scale, or warp
implicit functions. For example, a sphere implicit function
can be transformed into an oriented ellipse.
To create an instance of class vtkImplicitFunction, simply
invoke its constructor as follows
obj = vtkImplicitFunction
Methods
The class vtkImplicitFunction 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 vtkImplicitFunction class.
* string = obj.GetClassName ()
* int = obj.IsA (string name)
* vtkImplicitFunction = obj.NewInstance ()
* vtkImplicitFunction = obj.SafeDownCast (vtkObject o)
* long = obj.GetMTime () - Overload standard modified time
function. If Transform is modified, then this object is
modified as well.
* double = obj.FunctionValue (double x[3]) - Evaluate
function at position x-y-z and return value. Point x[3] is
transformed through transform (if provided).
* double = obj.FunctionValue (double x, double y, double z)
- Evaluate function at position x-y-z and return value.
Point x[3] is transformed through transform (if provided).
* obj.FunctionGradient (double x[3], double g[3]) - Evaluate
function gradient at position x-y-z and pass back vector.
Point x[3] is transformed through transform (if provided).
* double = obj.FunctionGradient (double x[3]) - Evaluate
function gradient at position x-y-z and pass back vector.
Point x[3] is transformed through transform (if provided).
* double = obj.FunctionGradient (double x, double y, double
z) - Evaluate function gradient at position x-y-z and pass
back vector. Point x[3] is transformed through transform
(if provided).
* obj.SetTransform (vtkAbstractTransform ) - Set/Get a
transformation to apply to input points before executing
the implicit function.
* obj.SetTransform (double elements[16]) - Set/Get a
transformation to apply to input points before executing
the implicit function.
* vtkAbstractTransform = obj.GetTransform () - Set/Get a
transformation to apply to input points before executing
the implicit function.
* double = obj.EvaluateFunction (double x[3]) - Evaluate
function at position x-y-z and return value. You should
generally not call this method directly, you should use
FunctionValue() instead. This method must be implemented
by any derived class.
* double = obj.EvaluateFunction (double x, double y, double
z) - Evaluate function at position x-y-z and return value.
You should generally not call this method directly, you
should use FunctionValue() instead. This method must be
implemented by any derived class.
* obj.EvaluateGradient (double x[3], double g[3]) - Evaluate
function gradient at position x-y-z and pass back vector.
You should generally not call this method directly, you
should use FunctionGradient() instead. This method must be
implemented by any derived class.
* FreeMat_Documentation
* Visualization_Toolkit_Common_Classes
* Generated on Thu Jul 25 2013 17:18:30 for FreeMat by
doxygen_ 1.8.1.1
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