Fit function to 3D curve

Dear all,

I'm trying to find the function that fits scattered my 3D data. It is however important that it is a curve because my 3D data points represent a centerline of an irregular structure. The general fit function only fits a surface. I need the function of the centerline to define perpendicular planes on the centerline.

Is there someone who can solve this problem?

Thank you in advance.

[Rik]

If you have a 'walking' variable like t, you could hack the system by generating 3 fits for each coordinate. If you don't have a t, you may be able to model it, e.g. by measuring the Euclidean distance to a starting point.

But there is most likely a much better solution.