vtkGenericDataSet

Section: Visualization Toolkit Filtering Classes

Usage

In VTK, spatial-temporal data is defined in terms of a dataset. The dataset consists of geometry (e.g., points), topology (e.g., cells), and attributes (e.g., scalars, vectors, etc.) vtkGenericDataSet is an abstract class defining this abstraction.

Since vtkGenericDataSet provides a general interface to manipulate data, algorithms that process it tend to be slower than those specialized for a particular data type. For this reason, there are concrete, non-abstract subclasses that represent and provide access to data more efficiently. Note that filters to process this dataset type are currently found in the VTK/GenericFiltering/ subdirectory.

Unlike the vtkDataSet class, vtkGenericDataSet provides a more flexible interface including support for iterators. vtkGenericDataSet is also designed to interface VTK to external simulation packages without the penalty of copying memory (see VTK/GenericFiltering/README.html) for more information. Thus vtkGenericDataSet plays a central role in the adaptor framework.

Please note that this class introduces the concepts of "boundary cells". This refers to the boundaries of a cell (e.g., face of a tetrahedron) which may in turn be represented as a cell. Boundary cells are derivative topological features of cells, and are therefore never explicitly represented in the dataset. Often in visualization algorithms, looping over boundaries (edges or faces) is employed, while the actual dataset cells may not traversed. Thus there are methods to loop over these boundary cells.

Finally, as a point of clarification, points are not the same as vertices. Vertices refer to points, and points specify a position is space. Vertices are a type of 0-D cell. Also, the concept of a DOFNode, which is where coefficients for higher-order cells are kept, is a new concept introduced by the adaptor framework (see vtkGenericAdaptorCell for more information).

To create an instance of class vtkGenericDataSet, simply invoke its constructor as follows

  obj = vtkGenericDataSet

Methods

The class vtkGenericDataSet 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 vtkGenericDataSet class.