HElp Plzzz.. vismat shrink as i render

my question is when I render the vismat that i applied on the object, the detail of the material becomes small. what should i do? enlighten me plzz with this problem

Re: HElp Plzzz.. vismat shrink as i render

is it something like what was mentioned in this post?

Re: HElp Plzzz.. vismat shrink as i render

thank u very much it help a lot