Hi Danny,

> now I'm just wondering if there are any
> programs that can do this ?

It seems like you might find it in some physics simulations where they try to model the behavior of rope for example.

Sometimes the curves in those kind of simulations are only made up of line segments though and not control point curves.


There is a command in Rhino called FixedLengthCrvEdit that you could try, it has a kind of constrained editing (kind of mush a single point picked on the curve to some other general direction or something like that) but maybe it would do what you need?

- Michael