  We obtain a three generational $SU(3)_c\times SU(3)_w \times U(1)^4\times
[SO(12)\times U(1)^2]^\prime$ model from an orbifold construction with the
requirement that three generations arise from twisted sectors. There exist
supersymmetric vacua realizing the standard model. In one example the anomalous
$U(1)$ breaks the gauge symmetry down to $SU(3)_c\times SU(2)_w\times
U(1)_Y\times SO(12)^\prime$.
