Hi Michael,

I've had some time to get into MoI again and I had a thought while modelling, is it possible to manipulate a minimum three pole curve without changing it's length?

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Hi Danny, re: manipulate curve without changing its length -

No, there isn't really any way to do that currently in MoI- it's not something that comes naturally with NURBS.

Something like that would have to be implemented as a kind of constraint system that would take your edits and then decide how to extend or contract the curve in a post processing step to modify your modification...

It could be possible to make a system like that, but it would involve a fairly elaborate mechanism with various ways to control it, there isn't any kind of inherent way to limit a NURBS curve in such a way, the fundamental structure of a NURBS curve is that it's made up of control points and if you grab and move one of the control points it modifies the curve and the curve's length changes as a result.

That kind of physical property retention in response to applied forces is kind of more in the realm of physics simulation.

- Michael

Okay, thanks for the clear explanation Michael.

It's interesting that you say it could be possible, now I'm just wondering if there are any programs that can do this ?

Cheers

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

Thanks again Michael, it's not anything I need desperately and I don't have Rhino, I tend not to download/buy software that I know I won't use or not ready to use.

Cheers