Acceleration or forces vs Bezier curves

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Pauvres_honteux
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Acceleration or forces vs Bezier curves

Post by Pauvres_honteux »

@Chris_G,
I had some thoughts in; Re: Sketcher: Bezier curves 162042

Abdullah replied with a suggestion to check your script/macro; Re: Sketcher: Bezier curves 162072

you wrote; Re: Sketcher: Bezier curves 158220

any thoughts around my thoughts? ;)
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Chris_G
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Re: Acceleration or forces vs Bezier curves

Post by Chris_G »

Hi,
I am probably not very qualified to answer to this.
But I have read that roller coasters, train "roads", are designed so that they minimize curvature ( that is, I think, centrifugal acceleration ).
The comb plot included into the Sketcher BSpline curve tool can indeed help visualize the curvature flow.
In that case you'll want to model your curve with lowest possible variations of the comb plot.
But that is "freehand" design, while the projects you are referring, are, I think, solved by accurate calculation.
Chris
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Pauvres_honteux
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Re: Acceleration or forces vs Bezier curves

Post by Pauvres_honteux »

Okey, I understand what you write.
What do you say about the possibility to show a value per "vally" and "peak"? It really would go a long way, anyway! ;)

As a bonus one would see, by a glance, if two geometric elements have the whished for transition between them.
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Chris_G
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Re: Acceleration or forces vs Bezier curves

Post by Chris_G »

I'm not sure that the numerical values of the curvature are really meaningful in curve design usecase.
I don't even know what is the unit of a curvature value.
In my comb plot tool, the curvature values are scaled according to the edge length.
So, indeed, if you want to compare the comb plots of 2 edges, they need to share the same scale factor.
So you can either select multiple edges to create a unique comb plot object for all of them.
Or you can select several comb plot objects and apply a common scale factor to all of them :
CombPlot.jpeg
CombPlot.jpeg (12.26 KiB) Viewed 1300 times
And it is also possible to select an existing comb plot object and additional edges and run the tool again, so that the additional edges are added to this existing comb plot.
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microelly2
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Re: Acceleration or forces vs Bezier curves

Post by microelly2 »

Chris_G wrote:I'm not sure that the numerical values of the curvature are really meaningful in curve design usecase.
The inverse of the curvature is the radius of a circle arc approximation of the small curve segment at a point.
It makes sense to lower bound this radius if you bend the material and want not to break it.
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