Yep the export is already done! I used TinkerCAD a ton for things ways more complex than it should be used to, so even when I use more advanced CADs at this point I tend to think in SDF terms. For many things it's faster and more natural than extruding, rotating, ... But the fact is, the engine behind TinkerCAD is quite good, but there is little interest for AutoDesk to compete with its own Fusion360, so TinkerCAD is left forever as a children / beginners tool, without the more advanced stuff that could implement.