# Welcome To ParaView

- Copyright Notice
- Introduction
  - The Origins of ParaView
  - Features
- Compiling ParaView
- Execution

Copyright Notice

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# Introduction

Welcome to ParaView, an application designed with the need to visualize large data sets in mind. The goals of the ParaView project include the following:

- Develop an open-source, multi-platform visualization application.
- Support distributed computation models to process large data sets.
- Create an open, flexible, and intuitive user interface.
- Develop an extensible architecture based on open standards.

ParaView runs on distributed and shared memory parallel as well as single processor systems and has been succesfully tested on Windows, Linux and various Unix workstations and clusters. Under the hood, ParaView uses the Visualization Toolkit as the data processing and rendering engine and has a user interface written using a unique blend of Tcl/Tk and C++.

The Origins of ParaView
ParaView is being developed by Kitware in conjunction with Jim Ahrens of the Advanced Computing Laboratory at Los Alamos National Laboratory. ParaView is funded by the US Department of Energy ASCI Views program as part of a three-year contract awarded to Kitware, Inc. by a consortium of three National Labs - Los Alamos, Sandia, and Livermore. The goal of the project is to develop scalable parallel processing tools with an emphasis on distributed memory implementations. The project includes parallel algorithms, infrastructure, I/O, support, and display devices. One significant feature of the contract is that all software developed is to be delivered open source. Hence ParaView is available as an open-source system.

Features
The following summarizes the important features of ParaView.

Visualization Capabilities:

Handles structured (uniform, non-uniform rectilinear grids as well as curvilinear grids), unstructured, polygonal and image data
All processing operations (filters) produce datasets. This allows the user to either process further or to save as a data file the result of every operation. For example, the user can extract a cut surface, reduce the number of points on this surface by masking and apply glyphs (for example, vector arrows) to the result.
Contours and isosurfaces can be extracted from all data types using scalars or vector components. The results can be colored by any other variable or processed further. When possible, structured data contours/isosurfaces are extracted with fast and efficient algorithms which make use of the special data layout.
Vectors fields can be inspected by applying glyphs (currently arrows -vector arrows-, cones and spheres) to the points in a dataset. The glyphs can be scaled by scalars, vector component or vector magnitude and can be oriented using a vector field.
A sub-region of a dataset can be extracted by cutting or clipping with an arbitrary plane (all data types), specifying a threshold criteria to exclude cells (all data types) and/or specifying a VOI (volume of interest - structured data types only)
Streamlines can be generated using constant step or adaptive integrators (currently, streamlines are not available in parallel, this feature is under development). The results can be displayed as points, lines, tubes, ribbons etc. and can be processed by a multitude of filters.
The points in a dataset can be warped (displaced) with scalars (given a user defined displacement vector) or with vectors (unavailable for rectilinear grids).
With the array calculator, new variables can be computed using existing point or cell field arrays. A multitude of scalar and vector operations are supported.
Data can be probed on a point or along a line. The results are displayed either graphically or as text and can be exported for further analysis.
ParaView provides many other data sources and filters by default (edge extraction, surface extraction, reflection, decimation, extrusion, smoothing...) and any VTK filter can be added by providing a simple XML description (VTK provides hundreds of sources and filters, see VTK documentation for a complete list).

Input/output and File Formats:

Supports a variety of file formats including: VTK (all types including parallel, ascii and binary, can read and written) EnSight 6 and EnSight Gold (all types including parallel, ascii and binary; multiple parts are supported -each part is loaded separately and can be processed individually) (read only) Plot3D (ascii and binary, C or Fortran; support for multiple blocks -each block is loaded separately and can be processed individually-, I blanking is currently partially supported) (read only) Various polygonal file formats including STL and BYU (by default, read only, other VTK writers can be added by writing XML description)
Since ParaView is open source, the user can easily provide her own readers and writers.
New flexible XML based file formats (which fully support distributed data) are being developed and prototypes are provided with ParaView.

User Interaction:

Intuitive and flexible interface based on the Tcl/Tk toolkit.
Compact user interface design. All tools are located in the main window. This eliminates the need for large number of windows which are often difficult to locate on a cluttered desktop.
Allows changing the parameters of many filters by directly interacting with the 3D view using 3D widgets (manipulators). For example, the user can manipulate the seed line of a streamtrace filter by clicking on a control point and dragging the line to the new location.
Maintains interactive frame rates even when working with large data through the use of level-of-detail (LOD) models. The user determines the threshold (number of points) beyond which a reduced version of the model is displayed during interaction (the size of the model can also be adjusted). Once the interaction is over, the large model is rendered.

Large Data and Distributed computing:

Runs parallel on distributed and shared memory systems using MPI. These include workstation clusters, visualization systems, large servers, supercomputers etc.
ParaView uses the data parallel model in which the data is broken into pieces to be processed by different processes. Most of the visualization algorithms function without any change when running in parallel. ParaView also supports ghost levels used to produce piece invariant results. Ghost levels are points/cells shared between processes and are used by algorithms which require neighborhood information.
Supports both distributed rendering (where the results are rendered on each node and composited later using the depth buffer), local rendering (where the resulting polygons are collected on one node and rendered locally) and a combination of both (for example, the level-of-detail models can be rendered locally whereas the full model is rendered in a distributed manner). This provides scalable rendering for large data without sacrificing performance when working with smaller data.

Scripting and extensibility:

ParaView is fully scriptable using the simple but powerful Tcl language. Every operation has a corresponding script command. Every command executed during a session can be saved in a trace file which can be re-loaded to reproduce the session. Furthermore, since the session file is simply a Tcl script, it can be edited/modified and loaded to obtain different results.
Additional modules can be added by either writing an XML description of the interface (since the XML interface is still being developed, it is not fully documented and is subject to change) or by writing special C++ sub-classes of the main ParaView module (this is only needed for advanced modules). The XML interface allows users/developers to add their own VTK filters to ParaView without writing any special code and/or re-compiling (ParaView can load shared Tcl wrapper libraries at run time).
Since the user interface is written with Tk, it can be modified and extended at runtime either from the command prompt or by loading a ParaView script. For example, it is possible to write a demonstation script which brings up a message window describing the current operation as well as allowing the user to interrupt the demo.

# Compiling ParaView Complete

ParaView uses the CMake cross-platform build system. To compile ParaView, you will have to install CMake. Binary and source distributions of CMake can be found here. If it exists for you platform, we highly recommend using a binary distribution. CMake 1.4.5 or newer is required.

The complete distribution of ParaView contains VTK and Tcl/Tk 8.3.2. You do not have to download VTK or Tcl/Tk separately to compile.

Run CMake and Compile
Once CMake is installed, you are ready to build ParaView. We highly recommend reading the CMake documentation if you are not familiar with CMake: http://www.cmake.org/HTML/Documentation.html. (You can skip the Developer's Guide.) In summary, ParaView Complete build consists of:

1. Running one of the CMake user interfaces
2. Changing configuration options
3. Compiling (make on Unix, Visual Studio on Windows)

On Windows, you should use the CMakeSetup.exe application to setup the VTK and ParaView build. On Unix/Linux, you should use the CMake wizard (cmake -i) or the terminal interface (ccmake). See the CMake documentation for details.

ParaView distribution is designed such that all the default build options selected by CMake for VTK and ParaView are appropriate for building ParaView. However you might have to tell CMake the location of some include files and libraries (for example MPI libraries if you enabled MPI support).

### Unix/Linux

The following instructions only apply to Unix/Linux systems. First we will give you the quick and dirty way to build ParaView:

1. untar the ParaViewComplete distribution
2. cd ParaViewComplete06
3. cmake -i (run cmake in wizard mode, where you have to answer questions about the build)

   or

   ccmake (run the terminal based interface to cmake where you interactively change build options)

4. if necessary change build options
5. make

It is a very good idea to tell cmake what C and C++ compilers you will be using. This can prevent many build problems. On most systems you can pass this information to CMake in the following way:

      env CXX=/your/C++/compiler CC=/your/c/compiler cmake

otherwise you must set CXX and CC in your environment and then run ccmake (or cmake -i).

If you are planning to build ParaView for multiple architectures then you can either make a copy of the entire ParaView tree for each architecture and then follow the instructions above. Or you can have one copy of the ParaView tree and compile it in a different manner (out-of-source). Instead of running cmake from the ParaViewComplete06 directory, create a new directory where you have some free disk space (not in the ParaViewComplete tree), a possible name would be paraview06-solaris. cd into this directory and then run cmake similar to the following example:

    ls /home/joe_user
    ParaViewComplete06 paraview06-solaris paraview06-sgi

    cd paraview06-solaris
    ccmake /home/joe_user/ParaViewComplete06
    or
    cmake -i /home/joe_user/ParaViewComplete06

This will create makefiles in the paraview06-solaris directory. Then you can run make in paraview06-solaris to compile ParaView. Repeat this process for each architecture you wish to build. Please note that on some platforms, it might be necessary to use the GNU Make to compile out-of-source. This is due to the fact that the Tcl/Tk build process uses some features not available on all make distributions.

### Windows Installation

The Windows build process uses the CMake GUI, CMakeSetup. After running CMake, you use the compiler make utility to compile as follows.

1. Install ParaView distribution by unzipping into the appropriate directory.
2. Execute CMakeSetup. This will pop-up a little GUI that allows you to tailor the build. It then starts building .dsw and .dsp files (Visual Studio 6), solution files (Visual Studio .NET ) or makefiles (nmake, Visual Studio 6 and .NET). You'll have to tell CMakeSetup where you've placed your ParaView source code, and where to build the object code and dll's (we'll call it "paraviewbin").
3. When CMakeSetup completes, start up Visual Studio and load ParaViewComplete.dsw or ParaViewComplete.sln. Select the ALL_BUILD project, and build it.

We recommend a 300MByte minimum swap size or you might have trouble during the link phase.

# Execution

For information about how to start and use ParaView, see the online documentation.