Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

How to model a building with a core (stairway, elevator shaft,...) surrounded with a corridor (a space inside a space) in OS?

asked 2016-04-08 04:10:01 -0500

DavidFGG gravatar image

updated 2016-04-08 04:42:07 -0500


my model is a multistorey building, which has offices spread next to the envelope of the bulding and in the core (actually 2 cores) of the building it has a corridor arround other spaces (restroom, elevator shaft,...). To better understand the situation see the picture bellow.

Top wiew.JPG

So when i model the building core, i have to make a space inside a space. And here comes the problem, because the floor and the roof of the bigger space are extended across the whole surface of the bigger space, I get two floors and two roofs at the place of the smaller space. And in my case I have vertical shafts from the bottom to the top, which are divided by the roof and the floor of the biger space (see image bellow).


When i dellete the surfaces (which devide my shafts), they just come back the next time i open the model. Also i have problems with the boundary conditions. ( See imagees bellow).

Bundary coditions.JPG

Boundary conditions 2.JPG

Is it possible to make a space with a hollow core without the roof and the floor just overriding the hollow core? And if, can i put a smaller space in the hollow core of the bigger space?


p.s. Sorry for the long text, but i want to make my problem as clear as possible.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2016-04-08 08:48:36 -0500

Adam Hilton gravatar image

updated 2016-04-08 09:46:11 -0500

Yes. You have to remove the piercing geometries. In EnergyPlus/OpenStudio every interior boundary has to be made up of two co-planar surfaces from two different spaces. When you are piercing through one space with another, you aren't satisfying this condition. It will cause incorrect intersecting and surface matching when using the OS routine. As for the fix, see the following...

Here I have made a small mockup of what I think represents your problem. Observe the exterior bounded surfaces that should be interior. image description

Enter into the space where you'd like the hollow center and trace with the pencil where the piercing geometry intersects the plane of your active space. Do this on both the ceiling and floor surfaces of the space (I've only shown the ceiling). image description

Now in x-ray view in the same space of interest, draw lines the with pencil tool again connecting the four corners of the ceiling and floor rectangles to create walls. You should have something to the following effect. image description

Delete the two rectangles and BAM, hollowed out space. image description

A quick intersect and surface match operation reveals our success. Note that I only did the top space, You can still see the errors in the bottom space. image description

Hope that answers your question.

EDIT: You'll need to add additional lines to ensure that every surface is "closed". I like to keep all my surfaces square, so I commonly take the approach seen in the following graphic. Or as David suggests in the comment, corner to corner would also work.

image description

edit flag offensive delete link more



Keep in mind that no base surface, either in OpenStudio or EnergyPlus, can have a hole in the middle. In your picture of the hollowed out space above you have a doughnut shape roof and floor. You need to split the roof and floor up into at least two separate shapes that don't have a hole on their own, even though the combined result is a hole. Typically you might draw lines from the outer conners to the inner corners, resulting in 4 trapezoid surfaces.

David Goldwasser gravatar image David Goldwasser  ( 2016-04-08 09:30:04 -0500 )edit

Ah yes, an oversight on my behalf. I added an edit to my answer. Thanks for the catch.

Adam Hilton gravatar image Adam Hilton  ( 2016-04-08 09:46:52 -0500 )edit

OK. Tnx adhilton for your ilustrational answer, and David for your addition. This works now,

DavidFGG gravatar image DavidFGG  ( 2016-04-08 10:31:16 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools



Asked: 2016-04-08 04:10:01 -0500

Seen: 2,458 times

Last updated: Apr 08 '16