Plenum Spaces Revit MEP 2011

I found a some new features in Revit MEP 2011 that is very useful for dealing with Plenum Spaces. First, you can set a type property of a level to tell the use of the level is for plenum space. This helps by creating a specific views for plenums, and all spaces added in these views will be assigned as plenums (instances property). Second item is the new instance property in spaces that assign it has a plenum space. This new property will allow for better calculation

Why are these plenum spaces relevant? Without plenum spaces the energy model for Heating Cooling Loads will be in accurate. Also you find that your gbXML exports not to work very well.

Site Analysis- Permeable vs Non-permeable

How about using the AREA tool to create a visual analysis of Permeable vs Non-permeable surfaces on a site plan. Revit can easily be used to compare the areas in both numerical view (Schedule) or visual with a color fill plan. An idea is to create a permeable parameter. You can then create a new view change view settings to see the site objects. Create some spaces and fill the parameter for permeable with Permeable or Non-permeable. Apply color fill based on permeable parameter. Finally create a schedule to extract information for square footage of each.