# Draw Curve With Constant Length

Hi there
how can I draw an Arc with constant length and with different radius of arc in GH? in Arc component in grasshopper when I change the Radius, the length of arc will be changed. I want to have the constant length.

Math!

`s = 2 π r (θ/360°)` (if θ is in degrees)

The length of the arc is directly related to radius and angle of the arc.

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thanks @Joseph_Oster and @seghierkhaled , i think it’s better i say that i want a curve, because, i want with change of radios , the curve go more curved. i want to have a curve with the constant length and with various radios and constant start and end points

In other words, you want a spiral. Search the forum for “spiral”:

https://discourse.mcneel.com/search?q=spiral%20category%3A2

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sorry, unfortunately it didn’t work to me.

If an approximation with the catenary is not enough for you, you should explain better what you want, since what you have said can be interpreted from having no solution to having infinite solutions.