For some reason I could not reply on previous post. But happy to disagree with you on SDF feasibility for real-time, Sascha. My friends at Gray Marchers just did this, all models done with SDF Modeler.. https://graymarchers.github.io/demonscene/DEMONSCENE.html
Took me a second to connect the dots. I think there was a misunderstanding. I don't think it's impossible in general, but the way SDF Modeler's splines are evaluated wouldn't really be suitable for real-time use.
You could, for example, simplify the problem by breaking the cubic curves into two quadratics.
Cheers,
Sascha