In this paper, by the example of solving the problem of constructing the temperature field in cryotherapy shows efficiency of geometric hashing performed on the basis of the NumPy package for constructing appropriate computational grid. Such an arrangement implies for each node to determine its position relative to the polygonal area of irregular shape. Such forms often modeled surfaces of internal organs. Solution build computational grid will allow for 3D visualization of the temperature field in the vicinity of cryotherapy, which will facilitate the timely temperature control.