# Introduction

OVITO is a scientific data visualization and analysis software for large-scale atomistic simulations in materials science and engineering. OVITO is freely available under an open-source license for Windows, Linux and Mac OS X platforms. It is being developed and maintained by Alexander Stukowski, a postdoctoral researcher at the Institute of Materials Science at Darmstadt University of Technology, Germany.

The first openly available version of OVITO was released in December 2009, after one and a half years of (part-time) development by the author, who, at that time, was a PhD student doing molecular dynamics simulations of nanocrystalline metals. Since that time, the software has further evolved, and its user base today comprises more than a thousand researchers from the computational materials science and engineering field. To introduce the new software package to the community, an article on OVITO was published in 2010.

OVITO is a software for visualizing and analyzing output data from atomistic simulations of particles, in particular molecular dynamics (MD) simulations of solid-state materials using classical interaction potential. Some noteworthy program features are:

- Input and output of various file formats used by MD simulation codes including LAMMPS, XYZ, CFG, IMD, and POSCAR

- Interactive display of a large number of particles using hardware-accelerated OpenGL rendering

- Visualization of polyhedral meshes

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

- Processing model: Data modification and analysis functions are arranged in a processing pipeline by the user; parameters can be altered at any time with immediate update of the results. Available modification functions include:

  - Slicing

  - Selection of particles based on user criteria (Boolean expressions)

  - Color coding

  - Transformation of particle coordinates

  - Calculation of derived particle properties using math formulas

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

  - Creation of atomic bonds

  - Manual selection of particles and display of particle properties

- High-quality image and movie output for publication

- A scripting interface

- Useful analysis functions:

  - Common neighbor analysis (CNA)

  - Bond-angle analysis

  - Centro-symmetry parameter

  - Coordination number analysis and radial distribution function

  - Displacement vector calculation

  - Calculation of atomic strain tensors

  - Histogram and scatter plot functions

  - Construction of surfaces from atomistics

  - Wigner-Seitz cell analysis for identification of point defects

- A modular software design that makes it easy to extend OVITO through plugins