  We have obtained simultaneous photometric and spectroscopic observations of
the cataclysmic variable 1RXS J064434.5+334451. We have calibrated the spectra
for slit losses using the simultaneous photometry allowing to construct
reliable Doppler images from H$\alpha$ and HeII 4686 emission lines. We have
improved the ephemeris of the object based on new photometric eclipse timings,
obtaining $HJD = 2453403.759533 + 0.26937446E$. Some eclipses present a clear
internal structure which we attribute to a central HeII emission region
surrounding the white dwarf, a finding supported by the Doppler tomography.
This indicates that the system has a large inclination angle $i=78 \pm
2^{\circ}$. We have also analysed the radial velocity curve from the emission
lines to measure its semi--amplitude, $K_1$, from H$\alpha$ and HeII 4686 and
derive the masses of the components: $M_1=0.82\pm0.06$ M$_{\odot}$,
$M_2=0.78\pm0.04$ M$_{\odot}$ and their separation $a=2.01\pm0.06$ $R_{\odot}$.
The Doppler tomography and other observed features in this nova-like system
strongly suggests that this is a SW Sex-type system.
