Hi Majid,

No, Ovito cannot generate atomistic models of polycrystalline microstructures for you. Please don't confuse the

Voronoi analysis function of Ovito with a "Voronoi crystal generator". The former constructs the Voronoi cell around each atom for characterizing the local atomic coordination, while the latter constructs the Voronoi cells for a given set of points in space (the "grain centers") and fills them with atoms on differently oriented crystal lattices.

Years ago I wrote my own Voronoi crystal generator code to produce initial starting configurations for my work on nano crystalline metals, but I think nowadays several codes have been published that provide ready-to-use solutions. Here is one example from a group in Germany that came to my mind:

http://www.gmp.ww.uni-erlangen.de/nanoSCULPT.phpYou also asked for the reverse process: How to reconstruct the grain boundaries from an atomistic model of a polycrystal. Such a "grain segmentation algorithm" is being developed for Ovito, but it's not publicly available yet. I still haven't found the time to finish the work.