  Polars (or AM Her systems) are cataclysmic variables without a disc due to
the strong magnetic field of the white dwarf. Most of their emission comes from
the region where the accretion column impacts the white dwarf and cools through
cyclotron and bremsstrahlung processes. We present a new code, CYCLOPS, to
model the optical emission from these systems including the four Stokes
parameters. It considers a three-dimensional region with the electronic density
and temperature varying following a \textit{shock-like} profile and a dipolar
magnetic field. The radiative transfer is solved in steps considering the
solution with non-null input radiation. The footprint of the column in the
white-dwarf surface is determined by the threading region in the equatorial
plane, i.e., the region from where the flow follows the magnetic lines. The
extinction caused by Thomson scattering above the emitting region is optionally
included. The fittings of observational data are done using a hybrid approach:
a genetic algorithm is used to seek for the regions having the best models and
then an amoeba code refines the search. An example of application to
multi-wavelength data of V834 Cen is presented. The fit found is consistent
with previous parameters estimates and is able to reproduce the features of
V834 data in three wavebands.
