There are a great many filters available in ParaView, and because ParaView has a modular architecture, it is routine for people to add new filters of their own design. <REFERENCE WIKI PAGE ON PLUGINS/PROGRAMMABLE FILTER>.
The most common filters are all available by clicking on the respective icon in the filters toolbar.
- Calculator - Evaluates a user-defined expression on a per-point or per-cell basis.
- Contour - Extracts the points, curves, or surfaces where a scalar field is equal to a user-defined value. This surface is often also called an isosurface.
- Clip - Intersects the geometry with a half space. The effect is to remove all the geometry on one side of a user-defined plane.
- Slice - Intersects the geometry with a plane. The effect is similar to clipping except that all that remains is the geometry where the plane is located.
- Threshold - Extracts cells that lie within a specified range of a scalar field.
- Extract Subset - Extracts a subset of a grid by defining either a volume of interest or a sampling rate.
- Glyph - Places a glyph, a simple shape, on each point in a mesh. The glyphs may be oriented by a vector and scaled by a vector or scalar.
- Stream Tracer - Seeds a vector field with points and then traces those seed points through the (steady state) vector field.
- Warp - Displaces each point in a mesh by a given vector field.
- Group Datasets - Combines the output of several pipeline objects into a single multi block data set.
- Group Extract Level - Extract one or more items from a multi block data set.
These eleven filters are a small sampling of what is available in ParaView.
In Alphabetical submenu of the Filters menu you will find the entire set of filters that are available in your copy of ParaView. ParaView currently exposes more than one hundred filters, so to make them easier to find the Filters menu is organized into submenus. These submenus are organized as follows.
- Recent - The list of most recently used filters sorted with the most recently used filters on top.
- Common - The most common filters. This is the same list of filters available in the filters toolbar and listed previously.
- Cosmology - This contains filters developed at LANL for cosmology research.
- Data Analysis - The filters designed to retrieve quantitative values from the data. These filters compute data on the mesh, extract elements from the mesh, or plot data.
- Statistics - This contains filters that provide descriptive statistics of data, primarily in tabular form.
- Temporal - Filters that analyze or modify data that changes over time.
All filters can work on data that changes over time because they are executed on each time snapshot. However, filters in this category will introspect the available time extents and examine how data changes over time.
- Alphabetical - An alphabetical listing of all the filters available. If you are not sure where to find a particular filter, this list is guaranteed to have it. There are also many filters that are not listed anywhere but in this list.
Why can't I apply the filter I want?
Note that many of the filters in the menu will be grayed out and not selectable at any given time. That is because any given filter may only operate on particular types of data. For example the <FILTER NAME> will only operate on <DATA TYPE> data so it is only enabled when the module you are building on top of produces <DATA TYPE> data. In this situation you can often find a similar filter that does accept your data, or apply a filter that transforms you data into the required format.
Searching through these lists of filters, particularly the full alphabetical list, can be cumbersome. To speed up the selection of filters, you should use the quick launch dialog. When the ctrl and space keys together on Windows or Linux or the alt and space keys together on Macintosh, ParaView brings up a small, lightweight dialog box like the one shown here. Type in words or word fragments that are contained in the filter name, and the box will list only those sources and filters that match the terms. Hit enter to add the object to the pipeline browser.
What does that filter do?
A description of what each filter does, what input data types it accepts and what output data types it produces can be found in Chapter <REFERENCE FILTER> and within ParaView's help system < LINK TO LOCATION IN REVISED HELP>. For a more complete understanding, remember that most ParaView filters are simply VTK algorithms, each of which is documented online in the VTK Doxygen wiki pages < LINK TO VTK/PV DOXYGEN>.
When one is exploring a given data set, one does not want to have to hunt through the detailed descriptions of all of the filters in order to find the one filter that they need at any given moment. It is useful then to be aware of the general high-level taxonomy of the different operations that the filters are grouped into.
- Attribute Extraction
- Topological operations
- Data Type Conversion
- White Box Filters