measurement of a surface without walls of delimitation

[com_che]

Hello, the old autocad, has a function for calculating a surface independently if it is closed or open.
Does revit have anything like that?
I just want to know how many square meters is a terrace that is not delimited by walls or a part of a garden, I can not use the local command, I found the instrument measure, but obviously measure the lunhgezza not the area.
How can I do that?

 

[Tristan]

use the local delimitation line
http://wikihelp.autodesk.com/revit/...1-locali661/0666-contorni666/0671-linee_di671