Some time ago I raised a similar topic in this [post](https://forum.freecad.org/viewtopic.php?f=8&t=57812). I'd love to see Nim working with Freecad too.
Nonetheless, I thing it will require a lot of effort (from my naive point of view). How to add an add-on is explained [here](https://wiki.freecad.org/Workbench_creation/en). But I think that it will require bindings to huge libreries: * The UI is done with Qt. * The 3D related UI is done with Coin3D. * The CAD engine is based on OpenCascade. I worked a lot on OpenCascade. You can find [occt.nim](https://github.com/mantielero/occt.nim) useful for this activity. We have seen in the forum some progress in the Qt front with [nimqt](https://github.com/jerous86/nimqt). I think Coin3d bindings would be needed. It would be interesting to have a Geometric Constrain Solver in Nim too. The low hanging fruit could be some bindings to Solvespace's constrain solver. I hope somebody takes this to the right level (I don't have enough knowledge). I wish we could do things like `cadquery` in nim too.
