Koen / Jonas is there a way to add a custom spring-curve by extending Framer's animator class using a module?
Please excuse my naïvety, I've really no idea if that's possible or not.
Yes you could. Depends on what exactly. If you inspect the source for simulators you should get some idea. But I can add some hints if you share you plan :-)
I've tried using SpringRK4Animator (https://github.com/koenbok/Framer/blob/b22d277d13618b6507f38f40db2626416536955c/framer/Animators/SpringRK4Animator.coffee) as a module-template, but an error pointed me to some app resources and so I gave up rather quickly ... ;)
So my current plan is to write a traditional module first to see if it works well enough that way ... otherwise I'll certainly come back to your offer :)