Importing data

To load a simulation file from your local computer in OVITO, select FileLoad File from the menu or use the corresponding button in the toolbar. OVITO detects the format of the file automatically (see list of supported formats). Compressed text-based files having a .gz suffix can directly be read by OVITO.

The imported dataset will appear in the viewports as a new object and is also represented by the first item under the "Data source" section of the pipeline editor, as highlighted in the screenshot on the right.

Select this list item to open the "External File" panel below the pipeline editor, which is also visible in the screenshot. The tool buttons at the top of the panel allow you to reload the input file in case has been changed outside of OVITO, or to pick a different file as data source of the pipeline. Replacing the input dataset can be helpful if you have set up a data analysis pipeline and want to apply it on a different simulation dataset.

Simulation sequences

OVITO can load trajectories consisting of a series of simulation snapshots. The following scenarios are supported by the software:

A series of files:

When you import a simulation file, OVITO tries to detect if it is part of a numbered sequence of files with similar names in the same directory. To this end, the last number (if any) in the filename you picked is replaced with the wildcard character * to generate a search pattern, which is subsequently used to look for other files belonging to the same sequence. For instance, if you imported a file named anim1c_5000.dump, OVITO will generate the search pattern anim1c_*.dump to find the other snapshots (e.g. anim1c_0.dump, anim1c_1000.dump, anim1c_2000.dump, etc). It is possible to manually override the generated file pattern in the input field highlighted in the screenshot.

One file containing multiple frames:

OVITO automatically detects when the imported file contains more than one frame and loads them as an animation sequence. For some file types, e.g. XYZ and LAMMPS dump, this is indicated by the Contains multiple timesteps checkbox highlighted in the screenshot. Note that OVITO typically keeps only the data of a single frame in memory at a time. Subsequent frames are loaded into memory only when needed, for example if you play back the animation or move the time slider.

Separate files for topology and trajectories:

Some MD simulation codes work with separate topology and trajectory files. The topology file contains the static definition of atoms, bonds, etc. while the trajectory file contains the computed trajectories and other time-dependent data generated by the simulation. In such cases you should open the topology file first (e.g. a LAMMPS data file). Then apply the Load trajectory modifier to load the time-dependent atomic positions from the trajectory file (e.g. a LAMMPS dump file). This modifier will combine both pieces of information -the static topology and the dynamic trajectory data- into a single animatable dataset.

OVITO will display a timeline and a time slider at the bottom of main window when a simulation sequence with more than one frame was loaded. Learn more about OVITO's animation functions in this section of the manual.