Automatic dimscale in viewports

I want bricscad to change dimscale factor for each viewport i have in Layouts. How can i do this?In AutoCAD there is an option in "ddim" panel call "scale dimensions to layout (paper scape)", And When i put a dimension automatically fit de scale of the viewport.My english is not so good. I wish you understand what i want and could answer me.Regards...Dario Tamburi