  We have developed a 3D version for the Modulated Spin Liquid in a
body-centered tetragonal lattice structure to describe the hidden order
observed in URu$_2$Si$_2$ at $T_0\approx17.5$ K. This second order transition
is well described by our model confirming our earlier hypothesis. The symmetry
of the modulation is minimized for ${\bf Q}\equiv(1,1,1)$. We assume a linear
variation of the interaction parameters with the lattice spacing and our
results show good agreement with uniaxial and pressure experiments.
