Python - Selecting exterior faces of walls from linked file

Hi All,


I am trying to select exterior faces of walls from a linked file and am running into some problems. This is part of a script intended to select doors within a linked file, then find the walls the doors are hosted to, and then place a family instance hosted to a chosen face of the host wall. Everything else is going smoothly, but I am running into problems with the exterior face of wall selection.


I have tried the following to select the exterior face:


<span style=“color: #75715e;”>#Get the side faces</span>
sideFaces = HostObjectUtils.GetSideFaces(walls[i], ShellLayerType.Exterior);
<span style=“color: #75715e;”>#access the side face</span>
refFace = (Doc.GetElement(sideFaces[0]).GetGeometryObjectFromReferencesideFaces[0])


However, this throws an error (Name ‘HostObjectUtils’ is not defined).


Has anyone had success selecting faces of walls from a linked model within Dynamo via nodes or Python / calling methods from the HostObjectUtils class? Any help is greatly appreciated.

Attached is a file demonstrating the error in question (The error should be repeatable with any Revit file with a file with doors linked in).