Release of boundary conditions

Good morning,

Could you please explain:
1 how can i set the bounds release for a QUAD element, i need only block the Z axis move for many elements by releasing all other degrees. But when I try to do it in sofiplus I get a problem on linear analysis. Im coching all the degrees exept the UZ, and I tried to also creating an spring but without success.

  1. For Desing ELU, could you explain to me how to disactivate some node and quad elements; because of the peaks values, I cannot perform a design analysis