Wrong height of IfcWindow?

edited July 28 in General

When I look at OverallHeight for sloping roof windows I get the projected height i Z and not the actual height of the window and wonder how to get this value? In the image the window should be 1010 mm wide and 1600 mm high.


  • It looks like it's giving you the angled Z axis height (529mm) and not the length (1600mm)
    That's my guess, that it takes the height from the bounding box not the window geometry, so in this case your bounding box isn't angled, I'm not sure how to fix it though, maybe check representations and edit/ rotate the bounding box if you can?

  • @Max possible to upload a parred-down version of your file, here?

  • Sure, I experience the same in every imported IFC-file including the Revit demo model.

  • Can you share the IFC file? The IFC file 'is' the native file for BB. If it's just the Blender file, that crucial connection is broken.

  • MaxMax
    edited July 28

    I can not share this model but the RAC basic sample file have the same problem when I open it in Blender. The window should be 1180 mm but overallheight is about 380mm.

  • OverallHeight is a standard attribute of an IfcWindow element. I think it is set by your exporting application rather than generated by IfcOpenShell on import.

  • MaxMax
    edited July 28

    Thanks, never thought of that. I have gotten many IFC-models generated by Revit and ArchiCAD and they have the same problem. Is there a way to get the actual width and height from BlenderBIM?

  • Nothing comes to mind :(

  • ..also, for unknown reason, OverallHeight is not an IfcWindowType attribute, so you have to find all your IfcWindow elements and reassign each of them even if they are typed

  • edited July 28

    Is there a way to get the actual width and height from BlenderBIM?

    Seems like it wouldn't be that involved to write a script that translated the IfcBoundingBox/XDim and IfcBoundingBox/YDim values into the IfcWindow's OverallHeight and OverallWidth attributes. Would only work for rectangular windows, obviously.
    ping @Coen since he's on a roll. ;)

  • I think it will only work if the object was rotated in local space and its transforms not applied, which unfortunately seems to be the case here since the origin of the object is far off from its logical rotation point

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