Forums Technical Discussion Is there any way to convert polygon to nurbs curve without a sharp corner?

Is there any way to convert polygon to nurbs curve without a sharp corner?

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bao007fei
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Is there any way to convert polygon to nurbs curve without a sharp corner?

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anon_user_40689665
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see attached,
use carve before convert.

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bao007fei
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cpb
see attached,
use carve before convert.
Thank you for help. It solve the problem partially. But it's hard to give me a perfect shape, like a perfect circle.
If there is a way to give result like the picture below. That'd be best.
Edited by bao007fei - 2019年3月9日 14:27:00

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Jim Rutherford
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try the fit sop…with interpolation
Edited by Jim Rutherford - 2019年3月9日 21:00:25
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DSpider
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1. Drop a “Circle” node.
2. Change the “Primitive Type” to “NURBS Curve”.
3. ???
4. PROFIT!
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bao007fei
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Just a simple example…
The point is I want to figure how to to convert a polygon to nurbs curve and keep the shape clean. No sharp corner and point variation. Just use the polygon points to generate a smooth, clean and closed nurbs curve.
Thank you all but the solutions above aren't robust enough.
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Jim Rutherford
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fit doesn't work?
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bao007fei
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Jim Rutherford
fit doesn't work?
It give the shape but bigger than I need.
I actually want to keep the points stay at their origin and get blue nurbs.

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Jim Rutherford
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okay…I think you can do what you want with a python sop using createNurbsCurve with the point positions…
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bao007fei
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Jim Rutherford
okay…I think you can do what you want with a python sop using createNurbsCurve with the point positions…
I'll check that. Thanks for the clue.
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Jim Rutherford
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another way would be to make a nurb circle with same number of points and wire your polygon into an attributeCopy sop and match the P
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bao007fei
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Jim Rutherford
another way would be to make a nurb circle with same number of points and wire your polygon into an attributeCopy sop and match the P
Wow. This is what I need. Simple and clever.Thank you very much.
Edited by bao007fei - 2019年3月11日 04:34:41

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OdFotan
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I go with the attribute copy method also,

But what is happening here under the hood? Is there nothing to detect, debug or solve such a thing? Why is one point completely near the curve and while all the other points keep a distance from the curve? By what is that controlled? By something the user could acces? or something hidden?

It seems so random and inexplicable, uncontrollable, like a bug or something.
Edited by OdFotan - 2021年5月4日 08:55:41

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tamte
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in the original file append Basis SOP, change U Parametrization to Uniform and you should get expected result
Tomas Slancik
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OdFotan
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Thanks, let me try that..

edit: it doesn't do it:
Edited by OdFotan - 2021年5月4日 16:48:40

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Denis Zaika
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Sorry for necroposting, just ran into a similar problem. It's easily solved with unclamp option in ends:sop, and uniform parametrization in basis:sop.
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