Getting Started With The Paraview Terminal (PvPython)

Welcome to this tutorial on getting started with PvPython, Paraview’s terminal that holds all the same functionality as Paraview’s GUI interface, but allows for an interface more familiar to terminal users. If you haven’t already, check out the Getting Started With Paraview tutorial here for the installation and basic functionality of the software. This tutorial will follow the same procedure as the GUI tutorial, of course, except that it uses the terminal. A note on using the terminal: PvPython is not particularly intuitive and not particularly well documented. If you're interested in creating scripts I would recommend reading this entire article (especially How To Find Python Commands) before getting started.

ParaView Terminal

To get started with PvPython, find the PvPython executable on your computer. This can be found in the Windows start menu by searching PvPython.

The first thing you should do after opening the terminal is run

from paraview.simple import *

This will give you all the base functionality. To access methods outside the simple package, those need to be imported separately.

Basic Example

Let's start off by creating a sphere and rendering it from the terminal.

First, you'll want to create a sphere object with the following:

sphere = Sphere()

This creates the sphere but we also need to “show” it to make it visible in the render. Do this by calling

Show()

Finally, to view the sphere call the command

Render()

This will bring up a window in which you can see your sphere. Notice that if you hover over this window it may say “Not Responding.” That is expected, the window will close when you close PvPython and will update whenever Render is called in the terminal. If you want, you can call

Interact()

to be able to interact with the view, including moving the camera, moving the window, and closing the window.

You may notice the sphere has a pretty low resolution. Let's try making it rounder by updating its parameters. Spheres have two parameters that contribute to their resolution: ThetaResolution and PhiResolution. ThetaResolution is the number of points you have for each horizontal plane (lines of latitude) and PhiResolution is the number of points in each vertical slice (lines of longitude). Let's try increasing both of these to get a better sphere.

sphere.ThetaResolution = 20
sphere.PhiResolution = 20
Render()  # Changes wont update untill Render() is called

There you go! The sphere should get a bit smoother. Feel free to mess around with different parameters and Render() them to see the result. A list of parameters can be seen by calling dir(sphere).

How To Find Python Commands

While some PvPython commands are intuitive or well documented, there are many commands that are difficult if not impossible to find information about. If this is the case and you're trying to find a way to do something you know you can do in the GUI version, you can use the following steps.

In GUI ParaView, click Tools → Start Trace from the toolbar. Click OK on the popup. Next, do whatever action you would like the PvPython command for. Once you're done, click Tools → End Trace and a window should pop up giving you the python commands for all the actions you did while the trace was running. This is also a useful way to build scripts without the need for a lot of coding. It is important to note however that the trace generates a lot of redundant or unnecessary code. If you want your program running as fast as possible, it's best to go through and only keep what you need.

Running PvPython or a PvPython script within ParaView GUI

To do this, all you need to do is click View → Python Shell from the toolbar. This will open a PvPython shell the same as the one in the terminal. At the bottom of this window, there is a button labeled Run Script. Clicking this will allow you to select a PvPython script to run within ParaView.