TikZ coding: how to create a space between a polygon and its nodes?

Question

I use TikX with LaTeX to draw a technical chart. I am trying to draw an irregular polygon around a group of named nodes in a tree. I got to

\draw [rounded corners, thick] 
   (node cs:name=add,anchor=north) --
   (node cs:name=cvc,anchor=west) --
   (node cs:name=addrc,angle=200) --
   (node cs:name=addrc,angle=-20) --
   (node cs:name=cnst,anchor=east) --
   cycle;

But the polygon is too close to the nodes. How can I either increase the polygon or indicate the best coordinates to get a diagram where there is some separation between the polygon and its nodes?

Answer 1

, , - "" , . outer sep=10pt . ( , ).

\node at (cvc) [name=fakecvc,outer sep=10pt,inner sep=5pt]{};

"" . (, ? rounded corners=20pt)

\usetikzlibrary{calc}
($(node cs:name=d,anchor=north)+(-10pt,+5pt)$)