FreeMat

- Main Page
- Related Pages

vtkExtractGrid

Section: Visualization Toolkit Graphics Classes

# Usage

vtkExtractGrid is a filter that selects a portion of an input structured grid dataset, or subsamples an input dataset. (The selected portion of interested is referred to as the Volume Of Interest, or VOI.) The output of this filter is a structured grid dataset. The filter treats input data of any topological dimension (i.e., point, line, image, or volume) and can generate output data of any topological dimension.

To use this filter set the VOI ivar which are i-j-k min/max indices that specify a rectangular region in the data. (Note that these are 0-offset.) You can also specify a sampling rate to subsample the data.

Typical applications of this filter are to extract a plane from a grid for contouring, subsampling large grids to reduce data size, or extracting regions of a grid with interesting data.

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

      obj = vtkExtractGrid

# Methods

The class vtkExtractGrid 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 vtkExtractGrid class.

- `string = obj.GetClassName ()`
- `int = obj.IsA (string name)`
- `vtkExtractGrid = obj.NewInstance ()`
- `vtkExtractGrid = obj.SafeDownCast (vtkObject o)`
- `obj.SetVOI (int , int , int , int , int , int )` - Specify i-j-k (min,max) pairs to extract. The resulting structured grid dataset can be of any topological dimension (i.e., point, line, plane, or 3D grid).
- `obj.SetVOI (int a[6])` - Specify i-j-k (min,max) pairs to extract. The resulting structured grid dataset can be of any topological dimension (i.e., point, line, plane, or 3D grid).
- `int = obj. GetVOI ()` - Specify i-j-k (min,max) pairs to extract. The resulting structured grid dataset can be of any topological dimension (i.e., point, line, plane, or 3D grid).
- `obj.SetSampleRate (int , int , int )` - Set the sampling rate in the i, j, and k directions. If the rate is > 1, then the resulting VOI will be subsampled representation of the input. For example, if the SampleRate=(2,2,2), every other point will be selected, resulting in a volume 1/8th the original size.
- `obj.SetSampleRate (int a[3])` - Set the sampling rate in the i, j, and k directions. If the rate is > 1, then the resulting VOI will be subsampled representation of the input. For example, if the SampleRate=(2,2,2), every other point will be selected, resulting in a volume 1/8th the original size.
- `int = obj. GetSampleRate ()` - Set the sampling rate in the i, j, and k directions. If the rate is > 1, then the resulting VOI will be subsampled representation of the input. For example, if the SampleRate=(2,2,2), every other point will be selected, resulting in a volume 1/8th the original size.
- `obj.SetIncludeBoundary (int )` - Control whether to enforce that the "boundary" of the grid is output in the subsampling process. (This ivar only has effect when the SampleRate in any direction is not equal to 1.) When this ivar IncludeBoundary is on, the subsampling will always include the boundary of the grid even though the sample rate is not an even multiple of the grid dimensions. (By default IncludeBoundary is off.)
- `int = obj.GetIncludeBoundary ()` - Control whether to enforce that the "boundary" of the grid is output in the subsampling process. (This ivar only has effect when the SampleRate in any direction is not equal to 1.) When this ivar IncludeBoundary is on, the subsampling will always include the boundary of the grid even though the sample rate is not an even multiple of the grid dimensions. (By default IncludeBoundary is off.)
- `obj.IncludeBoundaryOn ()` - Control whether to enforce that the "boundary" of the grid is output in the subsampling process. (This ivar only has effect when the SampleRate in any direction is not equal to 1.) When this ivar IncludeBoundary is on, the subsampling will always include the boundary of the grid even though the sample rate is not an even multiple of the grid dimensions. (By default IncludeBoundary is off.)
- `obj.IncludeBoundaryOff ()` - Control whether to enforce that the "boundary" of the grid is output in the subsampling process. (This ivar only has effect when the SampleRate in any direction is not equal to 1.) When this ivar IncludeBoundary is on, the subsampling will always include the boundary of the grid even though the sample rate is not an even multiple of the grid dimensions. (By default IncludeBoundary is off.)