Discrepancy in the geolocation of an IFC file (ifc2x3 or ifc4x) created by exporting the digital model using Civil 3D when the projection uses units in US Survey feet

Description

When an IFC file is created by exporting a Civil 3D model with an assigned coordinate system that uses US Survey feet, there is a slight shift in the geolocation when compared with the original Civil 3D feature class and the IFC features. 

The preceding image of ArcGIS Pro shows the coordinate system assigned in Civil 3D using US Survey Foot units.

The image above shows the offset between a feature class exported from an IFC file versus the original Civil 3D feature class.

Cause

IFC files do not support US Survey foot units.  

Solution or Workaround

The IFC file must be georeferenced to update its position, as described in the ArcGIS Pro help document: Georeference BIM data.