Animation View is used to set up animations in ParaView. It's is accessible through View | Animation View. This article describes this view and how to use it to create simple animations.
Figure 1 shows the the animation view. It is a standard dockable widget. There are three major portions to this panel:
Similar to animating any filter/source paramters, it is possible to animate the opacity or visibility of the object in all the views that it's shown. In the Parameter combo simply choose Opacity or Visibility when adding the animation track.
Time in ParaView
Before we delve any further into the world of animation, we need to understand time as ParaView implements it.
There are three types of times in ParaView:
- Animation Time:
- This is the time that changes as an animation is played.
- The VCR buttons in the toolbar, moving the time cursor on the animation view changes this animation time.
- The time-toolbar (Figure 3) shows the animation time.
- Reader Time:
- Certain file formats support associating time with datasets eg. exodus, XML VTK formats etc. This is referred to as a the reader time.
- The information tab shows the timesteps provided by any reader/data source (Figure 4).
- Note that when multiple sources provide time, ParaView assumes that they are all in the same time units.
- Application (TimeKeeper) Time
- This refers to the application wide time. This is the time value that ParaView requests from the readers/sources for showing data in any of the views.
- By default, this is linked with the animation time i.e. it's same as the animation time. However that can be changed by using the TimeKeeper-Time animation track on the Animation View. Double click on the track to pop-up the key-frames editor dialog which allows for setting this to a constant time value (useful in making animations where the data time should not change) or add explicit keyframes (Figure 5).
ParaView has three animation play-back modes. The mode as well as the parameters for each mode can be set in the scene properties section of Animation View (Figure 1).
- In this mode the animation is played as a sequence of frames evenly spaced in the specified Start Time and End Time for the animation. The No. Frames controls the number of frames in the animation. During playback, the animation time goes from Start Time to End Time incremented by (end time-start time)/(no. of frames) for every consecutive frame.
- Real Time
- In this mode the animation is played for the specified Duration in seconds (approx.). The animation time increases from Start Time to End Time. The number of frames actually rendered depends on how long each frame takes to render since the entire animation has to be done within the specified duration.
- Snap To TimeSteps
- This mode is useful when a file with data at different timesteps is opened. When in this mode, the animation time increases from Start Time to End Time producing exactly as many frames at the number of timesteps, with each frame corresponding to a timestep. One can think of this mode as going through the time-steps in a sequence.
Animate Data Timesteps
When a dataset with timesteps is loaded, ParaView detects it, updates the start and end times for the animation scene to match those provided by the reader and then switches the play mode to Snap To TimeSteps. Thus, there's no explicit setup that the user needs to do to cycle through the timesteps; simply hit play and ParaView will run through the time steps.