Minimum room size?

[mikeinsverige]

Revit Arch 2011
I am putting in rooms for the shafts so they can be labeled and coordinated throughout the project. One shaft is very small, and it appears that it may be too "small" to be a room object...is this possible?
The attached image shows the view after I moved the wall just a little bit, and it appears that the room size just passed the threshold and became too small. One moment before, the room was properly enclosed, but no longer. The threshold size seems to be about 0.7sm or about 1 SF.
Now, I have tried this in a new blank project, and a room can be any size, down to nearly 0.
But why in my project does the room become "not enclosed" upon reaching a certain size?

[mikeinsverige]

No thoughts yet on this one? Did I not explain it clearly?

[Dimitri Harvalias]

Mike,
it appears to be somewhat arbitrary.
When using room separation lines the minimum size seems to be limited to about 1sf. When using walls it appears to have some relationship to the wall thickness used.
See the attached image.
If walls are 150 wide then the minimum dimension of the room is 150. If some of the walls are 300 and some are 150 then it bottoms out about 85mm. If all the surrounding walls are 300 then I can get it down to virtually nothing.
Odd. Perhaps one to ask the factory?

[mikeinsverige]

Wow, I never thought about it depending on the wall size. Here I have 95mm (3.5") shaft wall so that may be exacerbating the situation then.

[Mike Sealander]

Check your sliver space setting and whether rooms are computed from center of wall, et.c

[mikeinsverige]

I adjusted the sliver settings but could not see a difference in how the room was affected. I am not sure how to check where Revit is calculating the room boundary. I assumed it was always at wall faces.

[Dimitri Harvalias]

You can set where Revit calculates from the room and area settings (the small arrow on the bottom of the room and area tab on the ribbon)
I didn't notice a difference adjusting those settings either. I believe the sliver space only comes into play when exporting to GBXML to tell Revit which enclosed areas should be ignored when calculating spaces.

[s.kamyab]

Hello,
I also changed the room Computation Height in type properties of the level , no luck.
Also replaced all walls with room separation line and unchecked walls to be not "room bounding", no luck again.

Cheers

[luke.s.johnson]

http://whatrevitwants.blogspot.com/2011/10/revit-minimum-room-size.html

[Basam Yousif]

We came across this issue last year. Upgrading an old project from Revit 2008 to 2011, caused room schedules to become much shorter. When investigating, we realized that all "small" rooms we had for fire closets and the like are no longer listed. Testing proved that rooms of area below 0.4 sq.m. do not function properly. We shared this with Autodesk and they confirmed that a bug existed and promised it to be addressed.

[mikeinsverige]

We got Revit 2012 recently, so I just tried this room size thing out again. Still, the room bottoms out around 0.1 square meters.

So, I have these three shafts in my project which will always say "not enclosed" ???

[SangHoon Hwang]

Is there any clear answer?
My guess is that the throat value of these problem is distance between wall center lines.
What if one room has a center line width approximately 1ft or shorter, then room area could not be placed into that room area.
It might be a limitation of revit program itself.
Even If so, I couldn't find the way to change that value.

Anyone has a good answer?

[Alfredo Medina]

I think the limit is the shortest length of a room's boundaries. It cannot be less or equal to 6".
I kind of agree with Revit in that a space that is smaller than 6.1" x 6.1" is not a room. :)
But any room whose shortest side is even slightly larger than 6" does create a room and does display its area in a schedule.
(Revit 2013 OneBox)

[pcelicamaja375856]

I managed to solve this issue by using model-in-place walls instead of regular walls. it worked for very small shafts.

[rbcameron1]

I was able to get it down to 4 1/4" X 4 1/4" before it cracked and gave me a warning. At that point I would start rethinking how I intend to use the room (either physically or schedule-wise) and re-design it to be more suitable. (see attached)