Rhino .3dm earlier versions
To save a model as an earlier Rhino file:
From the File menu, click Export Selected or Save As.
In the dialog box, in the Save as type box, select the Rhino version.
In the File name box, type a filename.
When saving Rhino V4.0 files to Rhino V2 files, the following changes take place:
Objects that contain non-NURBS geometry (spheres, cylinders, arcs, circles, etc.) are converted into NURBS objects. Sometimes this results in some less precise trimming curves. In particular, some geometry does not round trip V4 to V2 and back to V4.
Layers, materials, and object attributes are saved in simpler V2 formats.
Point clouds are exploded into single points.
Blocks are exploded into their component geometry.
The following data is not saved:
Annotation.
Render meshes and analysis meshes.
History information
Advanced texture mapping information.
Custom display information.
User data.
When saving Rhino V4.0 files to Rhino V3 files, the following changes take place:
V4.0 layers, materials, and object attributes are saved in simpler V3 formats.
The following data is not saved:
History information.
Advanced texture mapping information.
Custom display information.
User data.