Second Life Import of PRIMS

If you haven't checked it out yet, this site gives quite a bit of information for what you need to do: second life sculpted prims wiki

If you are reasonably skilled in 3d modeling programs, you can do a Blender solution for free.

Personally, for general modeling work, I use Hexagon 2, it has DWG/DXF import which works with Rhino 4's export functions, and it has a sculpties export function which I have never used.

I would imagine the process would go like this:

Open file in Rhino 4, export as AutoCAD file DXF or DWG

Import DXF or DWG file into Hexagon then export as Sculptie,

Then do secondlife things to import and texture your new sculptie.

This video gives more information on that last step.

Hope that helps :)

You may also want to have a look at BrlCAD, another freebie (in addition to Blender) that allows for a variety of different import formats. I have a bit of trouble with 3D *.dxf or *.dwg conversions to other programs. For 3D, *.stl works fine, most 3D programs can import that. *.stp or *.brep are also pretty common formats that transfer easily between applications...