Hello Xavier,
I could find time to add unit-based scaling to AI, unit based scaling is already available in wings version 2.3 of EPS and SVG if you can export or convert to those formats. Wings itself is unitless but the wings unit could be assumed to be 1cm. The EPS/SVG scaling units available are pt, pc, in, mm, cm and some others. The default scaling of "100pt" in the SVG import dialog can be changed to "1cm". Then 1cm shapes on the document should import consistently to 1 wings unit, assuming the SVG itself has physical dimension information.
I actually have a DXF importer in the works but it isn't ready as there are some bugs at the moment.
I could find time to add unit-based scaling to AI, unit based scaling is already available in wings version 2.3 of EPS and SVG if you can export or convert to those formats. Wings itself is unitless but the wings unit could be assumed to be 1cm. The EPS/SVG scaling units available are pt, pc, in, mm, cm and some others. The default scaling of "100pt" in the SVG import dialog can be changed to "1cm". Then 1cm shapes on the document should import consistently to 1 wings unit, assuming the SVG itself has physical dimension information.
I actually have a DXF importer in the works but it isn't ready as there are some bugs at the moment.