OK - have tried all manner of repair, uninstall / reinstall, deleting thumbnail caches. In short anything that seemed reasonable to try and was suggested.
Nothing has worked for the x64 version of V5. Nor can I seem thumbnails in x64 WIP. By this I mean I see no rendered thumbnails of .3dm files when I look in a directory. And LandDesign still neither renders plant models or 2D blocks/
However, I can see some thumbnails of normal .3dm in the V5 x86 version when trying to open a new files. But of course LandsDesign does not work in x86....
Does this give some clues as to what is broken?
When I reinstall at the moment, many of my toolbar preferences remain, which suggests the old install is not completely "blown away". Is there something I have to do to get a truly clean, clean install?
The inability to see .3dm thumbnails more generally from within Rhino has become quite troublesome as I try to select designed components for insertion...