@crysislinux another very good area for some nice documentation.

Currently, the 2D curves are based on Bezier curves. And the IO libraries convert various curve definitions into bezier curve definitions.

SVG paths can define bezier curves as well.

You'll find lots of online tutorials on how to create bezier curves. And hopefully, you will be able to apply some of those examples within JSCAD.

P.S. 3D bezier curves are called NURBS.