  We introduce a nonequilibrium off--lattice model for anisotropic phenomena in
fluids. This is a Lennard--Jones generalization of the driven lattice--gas
model in which the particles' spatial coordinates vary continuously. A
comparison between the two models allows us to discuss some exceptional, hardly
realistic features of the original discrete system --which has been considered
a prototype for nonequilibrium anisotropic phase transitions. We thus help to
clarify open issues, and discuss on the implications of our observations for
future investigation of anisotropic phase transitions.
