Creating Points on Min/Max Curvature?

Is there a tool in Rhino that indicates points along a curve where the curvature is at its minimum and maximum bends? The CurvatureGraph function is helpful in visualizing this but using ExtractCurvatureGraph only generates a set of 1 degree curves and no easy way to correlate this back to points on the original curve.

Similarly, is there a tool that extracts isocurves at minimum/maximum curvatures from a surface as visually indicated by the CurvatureAnalysis function?

Thanks for any help on this.



Mostly never mind but I would still like to know if it’s possible to extract points/curves from the CurvatureAnalysis function based on min/max values. Also doesn’t seem like Curvature marks maximum curvature points, just minimum.


i believe ExtractMinMaxRadiusPoints will do

Hi Jack -

The white points mark the maximum curvature points in a portion on the curve where the curvature starts to decrease in both directions from the points.

Yes - you are correct. I had that backwards re. min/max curvature.


Hi Jack - the Curvature command will also show you inflection points.


I’m not seeing an ExtractMinMaxRadiusPoint command anywhere - not in Rhino docs at least. Is this a built in command?

Hi Jack - does it work if you type the whole thing?
In V7, testExtractMinMaxCurvaturePoints
It seems not to be a test command in V8 but also not properly documented.


i dont see that command in v7 for instance, maybe thats the issue? maybe a new command in v8

@Jack_Billet yes that came with Rhino afaict

edit: strange thing is that you can not copy that command even in v8, it says unknown command, but it autocompletes

testExtractMinMaxCurvaturePoints doesn’t show up in v7. Not only that, it yields 0 google search results.

The only mention of ExtractMinMaxCurvaturePoints I can find is from a post @encephalon made back in November.

Sorry, it is ExtractMinMaxRadiusPoints - still not documneted as far as I can see- and testExtractCurvaturePoints and testExtractInflectionPoints are the test commands.


:smiley: now its getting really peculiar, in my v8 for mac it is called ExtractMinMaxRadiusPoints.

it is indeed only in v8 as far as i can tell.

It’s not peculiar, I am just home sick and not paying enough attention.



ok i am not going to ask indiscreet questions but it almost sounds like you are on a rocket around the moon… well good luck for your landing in that case :vulcan_salute:

FWIW, none of those commands work here in Rhino 8. Y’all are probably running a Pascal plug-in. Get well :beer:

Well, I thought of that before getting involved but I did not see anything in my heap. Ah - it is in the Garage plug-in from Dale F


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