Stiffness of the quad

How can I turn off the stiffness in one direction (e.g. along the Y axis) for a quad and have stiffness only for the X direction in sofimsha?

You can specify different orthotropic thicknesses:
Quad ... Tx/Ty/Txy/Td

However, I prefer doing it in Ase:
Grp2 ... QueA/QueX/QueY/QeMx/QeMy/etc
It allows to differentiate between membrane and bending stiffness as well as directions.