It is important to note that LogicalTopology is both the name of a namespace and the name of a class in the Autodesk.Map.IM.Data namespace. This means that this class must be fully qualified in your code (that is, always specified as “Autodesk.Map.IM.Data.Doc.Topologies.LogicalTopology” instead of simply “LogicalTopology”). One remedy is to add the following line to your code:
using Autodesk.Map.IM.Data.Doc.Topologies as TDDT;
You can then just write TDDT.LogicalTopology instead of the fully qualified name.