  We report a new and complete model of the beta Pictoris disk, which succeeds
in accounting for both the surface brightness distribution, warp
characteristics, the outer ``butterfly'' asymmetry as observed by HST/STIS in
scattered light, as well as the infrared emission. Our model includes the
presence of a disk of planetesimals extending out to 120-150 AU, perturbed
gravitationally by a giant planet on an inclined orbit, following the approach
of Mouillet et al. (1997b). At any time, the planetesimal disk is assumed to be
the source of a distribution of grains produced through collisional evolution,
with the same initial orbital parameter distribution. The steady state spatial
grain distribution is found incorporating the effects of radiation pressure
which can cause the distribution of the smallest particles to become very
distended. With realistic assumptions about the grains' chemical properties,
the modeling confirms the previously evident need for an additional population
of hot grains close to the star, to account for the 12 microns fluxes at short
distances from the star. It also indicates that this population cannot explain
the outer 12 microns flux distribution when the effects of gravity and
radiation pressure determine the distribution. Very small grains, produced by
collisions among aggregates, are tentatively proposed to account for this 12
microns outer emission.
