  Recent results of numerical simulations of fully nonlinear evolutionary
equations for long-crested deep-water waves are discussed, where formation of
extreme waves was observed. Several examples demonstrate that
three-dimensionality of the fluid motion has an essential influence on the
process of rogue wave formation. In particular, in the presence of elongate
wave groups, the most tall extreme waves occur when in an initial state the
wave fronts were oriented obliquely to the direction of the group. An "optimal"
angle, resulting in the highest rogue waves, depends on initial wave amplitude
and group width, and it is about 18-28 degrees in a practically important range
of parameters. Besides that, the mechanism of spatial-temporal focusing on a
random wave background has been simulated for several values of nonlinearity.
