When attempting to import a LandXML file created from StormCAD V8i into AutoCAD Civil3D, the file does not import properly and the following error appears:
"A pipe or conduit had an unsupported geometry."
This can occur due to a known issue with AutoCAD Civil3D. Apparently Civil3D does not support a trapezoidal channel for import from an XML file. The conduit type will need to be changed in the StormCAD file to a supported geometry type. It can then be exported to an XML file and imported into Civil3D.
Error importing a LandXML file from StormCAD into Civil 3D "A pipe or conduit had an unsupported geometry"