# How to identify the orientation of façade elements in IFC?

**URL:** <https://forums.buildingsmart.org/t/how-to-identify-the-orientation-of-facade-elements-in-ifc/4452>\
**Category:** IFC2x3\
**Tags:** ifc2x3\
**Created:** [October 25, 2022, 2:53pm UTC](https://forums.buildingsmart.org/t/how-to-identify-the-orientation-of-facade-elements-in-ifc/4452 "2022-10-25T14:53:19Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![pbourreau](https://avatars.discourse-cdn.com/v4/letter/p/3ab097/32.png) [@pbourreau](https://forums.buildingsmart.org/u/pbourreau)\
**Post date:** [October 25, 2022, 2:53pm UTC](https://forums.buildingsmart.org/t/how-to-identify-the-orientation-of-facade-elements-in-ifc/4452/1 "2022-10-25T14:53:19Z")

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Hi everyone,  
I am trying to extract with a simple Python script the façade elements (I am focusing on Walls and Windows only) according to their orientation from an ifc2x3.  
I am struggling in finding information on how to identify the orientation of an element. My idea woud be to first identify External IfcWalls (i.e. IfcWindows) and then to access another attribute or property them provides the orientation.  
It seems to me that the TrueNorth associated to a project is the entrypoint to my problem.  
Thanks!

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**Author:** ![aothms](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@aothms](https://forums.buildingsmart.org/u/aothms)\
**Post date:** [October 31, 2022, 1:31pm UTC](https://forums.buildingsmart.org/t/how-to-identify-the-orientation-of-facade-elements-in-ifc/4452/2 "2022-10-31T13:31:43Z")

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Hi Pierre (assuming it’s you),

For exterior elements, you might want to have a look at [GitHub - opensourceBIM/voxelization\_toolkit: Voxelization Toolkit for (IFC) Building Models](https://github.com/opensourceBIM/voxelization_toolkit) it comes with a predefined script to extract elements [voxelization\_toolkit/\_\_init\_\_.py at master · opensourceBIM/voxelization\_toolkit · GitHub](https://github.com/opensourceBIM/voxelization_toolkit/blob/master/python/voxec/ __init__.py#L136-L147)

For orientation it’s easiest to look at the IfcWall Axis representation that gives you the direction of the wall in 2D.

I’m not sure how often TrueNorth is correctly specified these days. I guess it’s superseded mostly by IfcMapConversion in IFC4. But in practice I guess on the average model these days neither are specified reliably.