Thank you for attaching a link, but the content in that link unfortunately doesn't answer what I was looking for.nThe forum says that the foundation stiffness for an elastic support 'offers stiffness per unit area' but the foundation stiffness in elastic support is in the units of N/mm? for a face of a solid. The forum is dedicated for an APDL command to implement the elastic support, whereas I want to know the difference between if I will add the elastic support, as compare to if I add a spring support to the same face. nThank you.n