Those occasionally using Google SketchUp may have noticed that the import function for .dxf files has vanished in the latest free version (v7.1). Why this should be I’m not sure (maybe Google’s licence to give it away free expired?), but getting those pesky old abandonware .dxf files — many of which seem to be low-poly — into SketchUp can still be done. Just install this free plugin (AllowDWGImportInSketchUp7.msi Windows installer).
To be frank though, it’s not usually worth the round-trip to 3Dxchange. Putting the .dfx into SketchUp, then the resulting .dae into MeshLab, usually results in a final .3ds file that iClone’s 3DXchange just refuses to load. A sad end for a file format that was apparently supposed to be about “enabling data interoperability” among different software packages.