Files with 3dh extension can be usually be found as special maps saved in the 3D highway base map format.
There is one other file type using
the 3DH file extension!
.3dh - SeisWorks horizontal time-slice format
3DH file extension - 3D highway base map
What is 3dh file? How to open 3dh files?
File type specification:
File extension 3dh is used for 3D highway base maps from Survey by New York State Department of Transportation.
The 3D highway base map is probably some sort of specialized engineering format.
This 3dh file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.
