Hi Mala, typically CAD modeling like MOI uses works best on things like mechanical parts.
A cushion is not at all similar to that, usually objects that have more organic shaping, localized lumps and bumps and similar are better to do in a polygon mesh based modeling program instead of in a CAD program like MOI.
ZBrush and 3D Coat are some good tools for that.
Although it is not really the right tool for that job there are some things you could experiment with in MOI though:
