hey!
is it possible to open a rhino4 model with a rhino3? cause i want to model in rhino4 on my laptop, but i want to render it with the computers of the school, en they still use rhino3…
let me know!
grtz
Save as a Rhino 3 file.
If you are looking for only rendering purpose, save in any format other than *.3dm (rhino format)… 
I think this should work.
ADD
http://www.coroflot.com/Abhinav_Dapke
You cau easily open rhino4 file in rhino3, even without saving in r3 format. It just tell you that some information will be skiped during loading, but do not worry, because these are only layers and material settings.