I am using the 90 day trial of Rhinoceros 5 right now and version 0.3.45.179 Beta of RhinoBIM.
I have some members that are curved with a constant radius, and I want to translate them over to SAP2000 v17 for analysis. I've tried exporting to an IFC and CIS/2 without any success. The only thing that I've been able to do is convert the curves into short, straight polylines and use a .dxf, which gets the geometry over to SAP but with a lot of little members.
Is it possible to translate curved members into SAP from Rhino?
I don't believe that rhinoBIM has implemented aspects such as revolved or swept members into their IFC export (whilst these are included in the coordination model view representation, very few software actually use them).
In this case, even if RhinoBIM exported it, SAP2000 will default the member to straight. For your interest, I've attached a file that includes a curved member to test.
As an alternative, you can consider using the geometry gym toolset that I develop. Using grasshopper, you can collect the path curves from the rhino document and directly assign SAP2000 frame elements from this. If they are nurbs, there are also tools in my plugins to rationalize to arc segments. You can also assign other attributes such as loads, releases etc etc. I also do have IFC tools (Rhino, GH and SAP2000) that can utilize these attributes including arc members if you need them.
There's some demonstration and explanations here