  We compare parameters of well-observed type II SN1999em derived by M.Hamuy
and D.Nadyozhin based on Litvinova-Nadyozhin (1985) analytic fits with those
found from the simulations with our radiative hydro code Stella. The difference
of SN parameters is quite large for the long distance scale. The same code
applied to models of SN1993J allows us to estimate systematic errors of
extracting foreground extinction toward SN1993J suggested by Clocchiatti et al.
(1995). A new implicit two-temperature hydro code code Supremna is introduced
which self-consistently takes into account the kinetics of ionization, electron
thermal conduction, and radiative losses for predicting X-ray spectra of young
supernova remnants such as Tycho and Kepler.
