surface equidistant da due superifici

[gatton]

Dear children, thank you for your help.
exists in caia a command that returns me the equidistant surface between s1 and s2 specified in figure?

 

[goccia]

with surface offset control.

 

[goccia]

on rhino there is the intermediate surface command, perhaps also cascade

 

[gatton]

Thank you very much