As one of the Solvespace maintainers I have a few comments: 1) You don't want just 2D constraints, 3D is better. If you were writing in C++ I'd say just take our constraint solver (Like Dune3D did). Since you're loving Rust, I can point you to the work of Michael F Bryan who wrote one in Rust and blogged about it here: https://adventures.michaelfbryan.com/posts/constraints-part-... I think his code is over at gitlab.…
You just told the developer of a non-open source project to take your GPL code. That is a recipe for a copyright dispute.
The first line of the article says "We're building a new open-source CAD program"