Does anyone know if there is a plugin available so that Autocad dwg files can be viewed in Opus?
If you can view the files within Internet Explorer then you may be able to add the dwg extension to the ActiveX Documents plugin to view them in Opus. (If it works in IE but not in Opus I might be able to fix it, although it would be hard since I don't have Autocad.)
If there's a QuickView viewer for them you may be able to use the Opus QVP plugin (available in the files section).
Otherwise you're probably out of luck.
Just came across this dwg Desktop and ActiveX viewer
Haven't tried it though.