Obtaining geometry that represents walls and window placement

Hey guys, I am struggling today with the gh Revit components.

What i want to access is a geometry that represents the gap in a wall created by windows, doors, etc, like that outlined below in yellow.

Wall → Host Inserts → Element Parts Geometry returns geometry of the door/window, but it usually includes door, frame and other geometries, all of which are ineffective for representing the open space in the wall. Creating a bounding box around one or all of the elements also fails to accurately represent this open space.

How else can I obtain a brep that accurately represents these spaces in the wall? Any suggestions?

Caught me as i’m about to head out the door. I’ll look into this again, but in the interim here is a quick GH solution

re-opening.gh (9.5 KB)

Hi @nglynn,

If you need something more accurate on curved or slanted walls try this.

RiR-WallOpeningsGeometry.gh (27.0 KB)

Hey Kike, thank you for the clever solution. It had crossed my mind to try using boolean operations but I have been struggling to get my lists and trees in order.

I notice this definition works best with a single wall and two or more elements. I’d like something a bit more robust that can work with as many walls and elements as I throw at it. Putting my head to understanding how that works and making necessary changes now…

Any leads, advice or explanation as to how that can be accomplished? Thanks for your time!


Hey thanks Japhy, I thought this was an interesting solution and definitely a good concept to understand for other potential use.

After running some purposefully convoluted test cases through, I noticed the definition sometimes picked up points from other walls, selecting an incorrect face from which to create a union box. I suspect the closest points component is to blame here and that I could solve the problem by more correctly structuring my data trees…

Please send tips or suggestions my way… Cheers!


re-opening.gh (22.1 KB)

Yeah, that’s a little tricky when it comes to branching when you get two opening.

Sorry, this gets pretty grasshoppery but will work on conditions with no walls, one opening or multiple.

re-opening2.gh (15.9 KB)