I'm also looking to convert a SketchUp file to a solid. (I think currently it's a wireframe, but for mold design / quoting apparently it needs to be a 3D solid model.)

Is there any way of doing this without expensive software? (with free/open source plug-ins?)

I've found ways to convert the SketchUp into STEP, IGES, STL, Parasolid, and had someone else convert it to .SLDPRT in SolidWorks; but apparently that's all still wireframe.

I looked at SUSolid (http://www.susolid.com/) , but I'm not sure if it will do what I want, and I don't want to spend the money on it in case it doesn't.

I also looked at Mesh to Solid from Sycode (http://www.sycode.com/products/mesh_to_solid/)- has anyone used this? It's $20 for 7 days; if it works well, that's not bad; but it might be a total waste if it doesn't work well. (And with several revisions possible over the course of a month or two, that gets pricey as well.)

Any suggestions? I'd like to convert my SketchUp design into a solid 3D ACIS (.sat) model, that I can then convert to .STEP, .IGES, etc. with CAD Exchanger. (which seems to work quite nicely)