.3DV

.3DV

3D Canoma file (MetaCreations Canoma (Wikipedia's Canoma history)).

.3DS

.3DS

3D Studio binary format file (Draw3D).
3D Studio mesh file (Autodesk 3DStudio Max and many other 3D applications).

.3DMF

.3DMF

3D Meta File (Apple Quickdraw 3D and 3D editors/viewers (Wikipedia's Quickdraw history)).

.3D2

.3D2

CAD 3D version 2 file (Antic Publishing's/Tom Hudson's Cyber Studio CAD 3D program for the Atari ST (Cyber Studio Wikipedia page) and many other programs).

.3D

.3D

Draw3D version 2 format file (Draw3D).
CAD 3D file = See .3D2 file (Antic Publishing's/Tom Hudson's Cyber Studio CAD 3D).