How can I calculate the interatomic distance of a crystal using Ovito?
It is difficult to answer this question without more information on your problem. Could you please provide some more details about your crystal?
Do you know its crystal structure? Is it a perfect, infinite crystal model or does it contain defects? Are the atoms positioned on ideal lattice sites or are they perturbed by thermal vibrations or elastic strains?
These details all play a role in choosing an appropriate approach for calculating the interatomic distance. For example, it may be sufficient to determine just a single neighbor distance of one pair of atoms or it may be necessary to calculate an average for all atoms in the crystal.
You can use the Coordination analysis modifier to get an overview over the distribution of interatomic distances in your system.