  The dynamics of the Broad Line Region (BLR) in Active galaxies is an open
question, direct observational constraints suggest a predominantly Keplerian
motion, with possible traces of inflow or outflow. In this paper we study in
detail the physically motivated BLR model of (Czerny & Hryniewicz, 2011) based
on the radiation pressure acting on dust at the surface layers of accretion
disk (AD). We consider here a non-hydrodynamical approach to the dynamics of
the dusty cloud under the influence of radiation coming from the entire AD. We
use here the realistic description of the dust opacity, and we introduce two
simple geometrical models of the local shielding of the dusty cloud. We show
that the radiation pressure acting on dusty clouds is strong enough to lead to
dynamical outflow from the AD surface, so the BLR has a dynamical character of
(mostly failed) outflow. The dynamics strongly depend on the Eddington ratio of
the source. Large Eddington ratio sources show a complex velocity field and
large vertical velocities with respect to the AD surface, while for lower
Eddington ratio sources vertical velocities are small and most of the emission
originates close to the AD surface. Cloud dynamics thus determines the 3-D
geometry of the BLR.
