Steve, over at RevitOpEd, posted a Stump-the-Chump question about a user not being able to place a room in the penthouse. Check out his post for the particulars then come back here for my explanation of what's happening...
Back? Good. So here's what I found:
The main roof seemed to be keeping the room from placing. If I raised the base of the Penthouse walls to be even with the top of the roof I could place the room.
If I offset the roof to be below the level I can place the room. If you could access the room’s “base offset” I think that you could raise that to the upper surface of the roof and you would be able to place the room, but I couldn't figure out how to access that parameter till after the room was placed, and if I changed it then, it didn't seem to matter.
So set the “base offset” of one wall (that’s all it took) to equal the roof thickness. This allowed me to place a room in the penthouse and outside the penthouse as well. Hmmmmmmm……
Now for the weirdness; I wanted to play with the rooms a little. I reset the “base offset” of the wall to 0’-0” and the room disappears. I figured that in AR (Actual Reality) you would never place a penthouse over the roof, you would have a floor there.
So I cut a hole in the roof and the room inside the penthouse appeared, but the one outside, did not. IF you look closely you will see that the second room is actually bound by the upper and lower surface of the roof.
I guess, since the room originates on the level... and roof is on the level... the room is “trapped” inside. I know the feeling… Sometimes I feel trapped in Revit. :)
I clearly spent WAAAY to much time on this. But, I can't help it... I LOOOOVVVVEEE Revit problems. It's kind of a stimulant that the logical mind just eats up. BTW, if you make the Main Roof not "bounding" the level acts as the base bounding plane for the room and the Upper Limit is what you set in the room parameters so the room displays correctly. That's what I would suggest as a fix for this particular problem, but that won't work if the room on the floor below is relying on the roof to be a bounding element. Cheers!