  Modeling stellar atmospheres is a complex, intriguing task in modern
astronomy. A systematic comparison of models with multi-technique observations
is the only efficient way to constrain them. Aims: We performed a
self-consistent modeling of the atmospheres of six C-rich AGB stars: R Lep, R
Vol, Y Pav, AQ Sgr, U Hya and X TrA, with the aim of enlarging the knowledge of
the dynamic processes occurring in their atmospheres. Methods. We used
VLTI/MIDI interferometric observations, in combination with spectro-photometric
data, and compared them with self-consistent dynamic models atmospheres.
Results: The models can reproduce SED data well at wavelengths longwards of
1{\mu}m, and the interferometric observations between 8{\mu}m and 10{\mu}m.
Discrepancies could be due to a combination of data- and model-related effects.
The models best fitting the Miras are significantly extended, with a prominent
shell-like structure, while the models best fitting the non-Miras are more
compact, showing lower average mass-loss. The mass loss is of episodic or
multi-periodic nature, but causes the visual amplitudes to be notably larger
than the observed ones. Stellar parameters were derived from the model fitting:
T_eff, L_bol, M, C/O, $\dot{\text{M}}$. Our findings agree well with literature
values within the uncertainties. T_eff and L_bol are also in good agreement
with the T derived from the angular diameter {\theta}_{(V-K)} and L_bol from
the SED fitting, except for AQ Sgr. Finally, {\theta}_Ross and {\theta}_(V-K)
agree with each other better for the Miras than for the non-Miras,which is
probably connected to the episodic nature of the latter models. We also located
the stars in the H-R diagram, comparing them with evolutionary tracks. We found
that the main derived properties from the model fitting are in good agreement
with TP-AGB evolutionary calculations for carbon stars (COLIBRI code).
