As we all well know, everything in Revit is constrained to a level - Whether the bottom of an element, or the top of an element. We still need to tell Revit that a window has a Sill Height of, for example, 600mm above a Level. Similarly, we can also add a window with a Head Height of 1000mm below a Level. What will happen though if one should copy these windows from one level to another? This Revit Recess post will investigate the effects thereof.
A simple project was created with windows placed. These windows have different elevation properties - The bottom windows have been placed with a Level Constraint of Level 1 (600mm Sill Height), with the upper windows having a Level Constraint of Level 2 (-2500mm Sill Height).
By copying these windows in the elevation view from Level 1 to Level 2, something interesting occurs: The upper windows on level 2 now measures from Level 2, instead of from Level 3 - In other words, they are not constrained by Level 3, -2500mm.
Another interesting thing occurs when copying the windows located on Level 2, over to Level 3: The windows on Level 3 are now referencing Level 2, and extracting the Sill Heights from the level it is copied.
There is actually a very simple explanation for this occurrence - Notice that the Level 3 Level Head in the images above is black. A black Level Head is a graphical notification that no Views have been assigned to that level: It is for reference purposes only, having Revit measuring the window Sill Heights from Level 2.
Once a View has been created from Level 3, the windows will now reference the correct Level Constraint.
Now the question is: How will this affect the MEP discipline?
The long answer to this question is..... Only to a certain extent. Ducting, Piping, Cabletrays and Conduits have a built-in parameter called Reference Level. This parameter ensures that the elements are referencing the level it has been placed on, or copied to.
Mechanical, Electrical and Plumbing Equipment - Created from any un-hosted family template, will have a built in Host parameter. This Host parameter typically extracts the level the element is currently residing on.
However, if any object is created from, for example, a Wall Based family template, the same behaviour applies as with Windows (Windows are also wall-based elements)