Deformations Boundary Conditions During a Soil Structure Interaction Analysis

Hi All,

I am studying the seismic response of a structure with soil structure interaction in Plaxis 3D 
About the dynamics boundary conditions I know that free field are probably the best way to reproduce the lateral soil,
obviously ensuring a certain distance between the structure and the borders.
My doubt concerns the Deformations Boundary conditions (in the Model Explorer), by default these are fixed in "normally fixed".
Should I also set these conditions as "free"? Or in a dynamic phase the "deformations boundaries" are ignored and only the "dynamics boundaries" are considered?
Thank you