A three-step procedure is proposed to investigate growth-induced polarity arising in centrosymmetric crystals of dipolar molecules. It is based on (i) calculation of molecular interaction energies by force field methods, (ii) determination of the morphology, and (iii) use of the energies in a Markov-type growth mechanism on faces (hkl). Applied to trans-4-chloro-4'-nitrostilbene (CNS), the procedure showed that CNS crystals, although globally centric, are composed of sectors exhibiting different polar properties. The sectors related to the +b and -b directions show opposite polarity and are mainly responsible for observed second-harmonic generation and pyroelectric effects. Influence of the calculation method on the results was investigated by comparing different force fields or charges.