# Introduction

OVITO is a scientific data visualization and analysis software for atomistic simulation models in materials science and related disciplines. OVITO is freely available for Windows, Linux, and macOS under an open-source license. It is being developed by Dr. Alexander Stukowski at the Materials Science Department of Darmstadt University of Technology, Germany.

The first version of OVITO was released in December 2009 and its initial feature set was described in a journal article about OVITO in 2010. Today OVITO has more than active 100,000 users from the computational physics, materials science, and chemistry fields.

## Program features

OVITO is a software for visualizing and analyzing output data from particle-based simulation models, notably molecular dynamics (MD) simulations of solid-state materials. Its main focus is on large simulation models based on classical potentials (103 - 108 atoms). Some noteworthy program features are:

- Input and output of various file formats used by MD simulation codes, including LAMMPS, XYZ, CFG, IMD, POSCAR, NetCDF, PDB, FHI-aims, CASTEP, and GSD/HOOMD.

- Interactive display of large numbers of particles and bonds using hardware-accelerated OpenGL rendering.

- Support for various particle shapes: spheres, cubes, ellipsoids, cylinders, and more.

- An easy-to-use interface, a flexible software design, and a data model that supports an arbitrary number of particle properties.

- High-quality image and movie rendering for publication and a keyframe-based animation system.

- A powerful Python-based scripting interface that allows one to automate analysis and visualization tasks and extend OVITO with new functions.

- Nondestructive data manipulation and analysis functions are arranged in a data flow pipeline by the user. Parameters can be changed at any time and results will be immediately recalculated. Available modification functions include:

  - Dynamic particle selections based on Boolean expressions

  - Color coding

  - Slicing and cutting

  - Transformation of particle coordinates

  - Computing new particle properties

  - Display of periodic images & wrapping of particles at periodic boundaries

  - Creation of atomic bonds

  - Manual selection of particles and inspection of particle properties

- Useful analysis functions:

  - Common neighbor analysis (CNA)

  - Bond-angle analysis

  - Centro-symmetry parameter

  - Coordination number analysis and radial distribution function

  - Spatial correlation function

  - Automated dislocation line identification (DXA)

  - Displacement vector calculation

  - Atomic strain tensor calculation

  - Local elastic strain calculation

  - Histogram and scatter plot functions

  - Reconstruction of geometric surfaces from atomistic models

  - Voronoi cell analysis

  - Identification of point defects using Wigner-Seitz cell method

- A modular software design, which allows to extend OVITO via C++ plugins