Polycrytalline structures are modeled via dynamically envolving power i.e. Laguerre diagrams in the three dimensional flat torus. Generating sites follow motion equations resulting from total (interface) enregy minimization., this results in an evolution of the associated structures with accompanying elementary topological tranformations. First computational results show good agreement of simulated with empirical data from real polycrystal, e.g. self similarity power law and so on.