# Curvature Graph?

The picture below contains some question.
Thanks in advance for everybody, who can help.
tibor
ps: and if You see the “V” parameters, one is Periodic degree, the other is Closed degree…what is the different and how can I convert one of them into the other? …thanks

1 Like

Hi rajznyolc -

If you make a closed curve using the Curve command with Sharp=Yes and Sharp=No you can see the difference between non-periodic and periodic - basically, periodic curves and surfaces have seams which cannot develop a kink - they are always smooth across the seam. Use MakePeriodic/MakeNonPeriodic to convert between the two. Periodic curves have ‘extra’ control points that wrap around the curve at the ends - the curve or surface overlaps itself in both directions- you don’t get to see these though - you only see and interact with the parts ending at the seam location.

Rational curves and surfaces have point weights that vary - use the Weight command to see and edit point weights on a circle (rational) and a curve from the curve command, (or a Circle modified using Rebuild).

The curvature of the Rhino surface appears to be continuous to me - it does drop to zero at the seam, but as far as I can see it remains continuous- that is, the outer graph line is not broken.

-Pascal

2 Likes

Dear Pascal,

thank You very much…I understood everything and solved the problem.

(T-Spline created a non-periodic surface and played a trick on me…I created (the darker blue part) manually a (rebuilded) surface, which was periodic.)

Thank You again, You helped me a lot.

Regards,

tibor

Date: Wed, 19 Nov 2014 15:59:04 +0000

From: steve@mcneel.com

Subject: [McNeel Forum] [Rhino for Windows] Curvature Graph?

November 19

Hi rajznyolc -

If you make a closed curve using the Curve command with Sharp=Yes and Sharp=No you can see the difference between non-periodic and periodic - basically, periodic curves and surfaces have seams which cannot develop a kink - they are always smooth across the seam. Use MakePeriodic/MakeNonPeriodic to convert between the two. Periodic curves have 'extra' control points that wrap around the curve at the ends - the curve or surface overlaps itself in both directions- you don't get to see these though - you only see and interact with the parts ending at the seam location.

Rational curves and surfaces have point weights that vary - use the Weight command to see and edit point weights on a circle (rational) and a curve from the curve command, (or a Circle modified using Rebuild).

The curvature of the Rhino surface appears to be continuous to me - it does drop to zero at the seam, but as far as I can see it remains continuous- that is the outer graph line is not broken.

-Pascal

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#### Previous Replies

rajznyolc

November 19

The picture below contains some question.

Thanks in advance for everybody, who can help.

tibor

ps: and if You see the “V” parameters, one is Periodic degree, the other is Closed degree…what is the different and how can I convert one of them into the other? …thanks

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