Fully 3D models of astrophysical maser clouds at VLBI scale are
used to test
several scenarios for the generation of astrophysical maser flares. These
include geometrical situations, such as rotation of prolate and oblate
spheroidal clouds and superimposition of clouds in the line of sight, as
well as variations in physical conditions, such as changes in pump and
loss rates, and
in the level of the amplified background radiation.
Light curves produced by the models will be compared with extensive
data on flaring in TypeII methanol and water masers to test the likelihood
of the different scenarios.