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### Data source

A data source is an essential part of every pipeline as it provides the input data that is passed to the modifiers. The data source of the current pipeline appears under the "Data source" section of the pipeline editor as depicted in this screenshot. Most of the time you will work with the External File data source type, which imports the input data for the pipeline from one or more files stored on your local computer or a remote machine.

Data source | Description
--- | ---
External file | Reads the simulation data from an external file.
Static source | Feeds a static dataset that is held in memory to the data pipeline.

#### External file

The "External file" panel lets you configure the parameters of the data source, in particular from which external file(s) the input data for the current data pipeline should be read. The panel is automatically displayed after you imported a data file via OVITO's Load File or Load Remote File menu functions. You can return to the panel at any time by selecting the topmost entry under the "Data source" section of the pipeline editor.

#### Toolbar functions

Pick new file

  Selects a different data file on disk, which will subsequently serve as new input for the current data pipeline. All modifiers in the pipeline are retained but the data they operate on gets replaced.

  Note that OVITO will not automatically detect whether the file you picked is part of a numbered sequence of files in the same directory. In order to load a series of files as a new animation, you need to manually enter a search pattern into the "File pattern" input field. Furthermore, note that OVITO will automatically adjust the viewports to fully show the newly loaded input dataset. If you would like to preserve the current view configuration, first use the Create Camera function from the viewport menu before loading the new data file.

Pick new remote file

  Same as above, but allows you to load data from a new remote URL instead of picking a file from the local filesystem.

Reload file

  Reloads the data for the current animation frame from the external file. This function is useful if the file contents have been updated or replaced, for example after re-running a simulation or editing the file in an external program.

Update trajectory frames

  Refreshes the sequence of animation frames. OVITO will search the directory to find new files matching the filename pattern and/or rescan the loaded file to discover any new animation frames that have been appended to the trajectory file.

Load entire trajectory into memory

  This option lets OVITO load all frames of the current trajectory into memory to speed up access to the data or enable smooth animation playback in the interactive viewports. Note that you should make sure first that your computer has sufficent free memory to hold all trajectory frames. If this option is turned off (the default), OVITO holds only a single frame of the trajectory in memory at a time to reduce the memory footprint.

#### File sequence - Search pattern

This section allows you to specify a filename search pattern to load multiple files from the same directory as one trajectory. The search pattern must contain a single '*' wildcard character, which will match any sequence of digits in a filename. All files matching the search pattern will be combined into one long trajectory, showing the contained simulation frames back to back. See also this section on how to import simulation trajectories.

OVITO automatically generates a default search pattern for you when importing a file with a number it its name. You can turn this behavior permanently off by unchecking the "auto-generate" option.

#### Trajectory - Playback ratio

After importing a new trajectory consisting of N simulation snapshots, OVITO will adjust the animation interval (which is shown as timeline below the viewports) to the same length and show one trajectory frame per animation frame. Thus, there will be a one-to-one relationship between imported trajectory frame and rendered animation frames.

If desired, this standard 1/1 frame ratio can be changed by pressing the Change button, which opens the Configure trajectory playback dialog (see next section).

#### Configure trajectory playback

This dialog lets you control how the snapshots from the loaded simulation trajectory are mapped to OVITO's animation timeline. You can change the default 1/1 mapping to either a 1/n mapping, in which case each trajectory frame is replicated and rendered n times, or to a n/1 mapping, in which case only every n-th trajectory frame will be rendered.

A 1/n mapping is useful if you want to stretch a simulation trajectory consisting of only relatively few snapshots and render a longer movie. OVITO provides the Smooth trajectory modifier, which can be applied to compute new intermediate frames by interpolating the particle positions of successive frames in the input trajectory.

A n/1 mapping is useful if the loaded simulation trajectory consists of excessively many snapshots and you want to render a short movie showing the whole trajectory but having fewer frames.

See also the advanced animations section for further information.

#### See also

`FileSource` (Python API) pro
`StaticSource` (Python API) pro

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