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orbingol / NURBS-Python

Object-oriented pure Python B-Spline and NURBS library
https://onurraufbingol.com/NURBS-Python/
MIT License
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Nurbs equally spaced points #99

Closed andreabonacini closed 4 years ago

andreabonacini commented 4 years ago

Hi, i'm using the Nurbs.curve class and i would like to get a set of equally spaced evaluated points over the curve, possibly as a function of an imposed delta (or sample size). Is it possibile? Regards, Andrea

orbingol commented 4 years ago

Evaluated points are equally spaced on the parametric space (UVW) where the evaluation happens. It might or might not be equally spaced on the XYZ space.

andreabonacini commented 4 years ago

So, is there a function inside the NURBS library in order to compute equally spaced samples on the XYZ space? The input of the function i would like to be progress step previewsly defined in the XYZ space

ebo commented 4 years ago

@andreabonacini, are you referring to arc-length parameterization of the NURB? ie. if you have a curve that is 6" long, and you evaluate it a 1" that it is 1/6'th of the way along the curve, or are you referring to something else?

andreabonacini commented 4 years ago

I was referring to if there was a method that takes as input a constant velocity (or a progress step) in order to obtain in output the parameter values that allow to have equally spaced points (cartesian coordinate) along the NURBS. Obviusly the parametrization u would not be equally spaced.

Anyway, for that purpose i successfully implemented my own algorithm of a constant feed rate. This solved the problem for me.

ebo commented 4 years ago

I would be interested in looking at it if you would be willing to share.

On Jul 28 2020 7:22 AM, Andrea Bonacini wrote:

I was referring to if there was a method that takes as input a constant velocity (or a progress step) in order to obtain in output the parameter values that allow to have equally spaced points (cartesian coordinate) along the NURBS. Obviusly the parametrization u would not be equally spaced.

Anyway, for that purpose i successfully implemented my own algorithm of a constant feed rate. This solved the problem for me.

orbingol commented 4 years ago

Anyway, for that purpose i successfully implemented my own algorithm of a constant feed rate. This solved the problem for me.

I think we can close this issue.