Create air volume model

I am trying to find a way to create a closed volume representing the inner side of walls, floor and roof in Rhino inside Rebit and wonder of somebody have some ideas? The Revit file might not contain any rooms or spaces and geometry should be as simple as possible. Inner walls and floors should be ignored.


Pollination is that best at this that i’ve seen, they are activity developing these tools for better integration as well.

Thanks a lot, yes, I really like Pollination but since it is in Beta and that I do not know the availability or license form of this plugin in the future I would like an alternative method.

What is the expected output geometry wise? tolerances for the volume? Corners, Sharp edges?

I assume you are trying to do this on multiple projects in an automated fashion.

The tolerance is quite crude, 1-2 dm is fine in plan. Preferable the geometry should be as simple as possible, for the attached image I would prefer two boxes, one with 6 sides and one with seven (2 for the roof). If not I will have to clean it up manually afterwards. The method will be used in multiple projects but there will it will be a semi automated process to verify the input and if possible, the level of detail.

The biggest challenge seems to be incoming Revit file variations possible. Not everyone is going to put Interior Walls on the Interior for example.

Assuming disorganized Revit files it would require a few GH definitions:
Figuring out which Walls are exterior.
Which Floors/Roofs to Keep, there may be cases where people are using floors as roofs.

As well as more traditional GH problems:
Identifying the correct faces to keep (inner only)
Extending the Surfaces to create a Boundary Volume.

I think we safely can assume that the Revit-files are highly disorganized. I am thinking of a semi manual method where I select a few enclosing surfaces (bottom floor, roof and a few falls) and this is extruded into a bounding volume. Still, no idea how to do this. I guess AI could be trained as well but that is even more difficult.

One other idea I have is to automaticly fill the building with rooms and merge these. Also, no idea how to do this.

That’s actually where i was heading.

Revit does a great job filling up the space via a Room Element.

The quickest way to accomplish this is one Room Element, making sure it goes to the bottom and top.

To get the not rectangle shapes you need to calculate volume for the room.

This quickly creates a simple brep of the entire volume

Thanks, I want a single volume even if there are a number of exsisting rooms and spaces in the model, is there a way to create this without editing internal walls and room bounding lines?

Yes, there is an Revit API method that can help here and we are working on getting a component out based on it to do just this. We’ll reply to this post once it’s in the Daily Build Wip Rhino.Inside.Revit.

This would be the best thing since sliced bread. Thanks.

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Looks like beams are not included when calculating room volume.
I created a simple model with single room and couple columns and beams in it. When calculating room volume geometry, it doesn’t include the beams when filling the room. So we end up with this.

But this is what I want to have. Other than doing solid difference, I wish there was a way to achieve it. Any updates on this?


I’m not seeing that Beams can be room bounding, although concrete beams might be able to.

Concrete beams are also not room bounding. I ended up getting their geometry and adding them as Ceiling Direct Shapes.

Nice work-around!

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I plan to use the air volume model to perform thermal simulations. Usually columns and beams are described as thermal bridges due to the complex heat flow and should not be included in the air volume. For comfort models, CFD and daylighting they should probably be included and therefore it would be great to have the option to include them or not.