Grasshopper

algorithmic modeling for Rhino

# Torsion in GH

I found this Rhinoscript for determining the torsion of a curve at a given point . Can anyone convert it to a GH script for me?

'''
''' Description
''' Evaluate the torsion of a curve.
''' Parameters
''' crv - a string that identifies the curve to evaluate
''' t - a parameter of the curve within its domain
''' Returns
''' The torsion if successful.
''' Null if the torsion is undefined at the parameter.
'''
Function EvaluateTorsion(crv, t)

' Local variables
Dim data, d1xd2, numer, denom

' Default return value
EvaluateTorsion = Null

' Calculate the torsion
data = Rhino.CurveEvaluate(crv, t, 3)
If IsArray(data) And UBound(data) = 3 Then
d1xd2 = Rhino.VectorCrossProduct(data(1), data(2))
numer = Rhino.VectorDotProduct(d1xd2, data(3))
denom = Rhino.VectorDotProduct(d1xd2, d1xd2)
If denom > 0 Then
EvaluateTorsion = numer / denom
End If
End If

End Function

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### Replies to This Discussion

Translated to the best of my abilities. I don't know if the result is actually correct though.

--

David Rutten

david@mcneel.com

Attachments:

As always, David, your willingness to assist is above and beyond. =)

Are you still going to add a torsion component into GH in the future?

I can certainly add this as a component. Do you think many people would use it?

--

David Rutten

david@mcneel.com

I added both a Torsion and a Derivatives component. Dropdown only as these are pretty darn geeky.

--

David Rutten

david@mcneel.com

Sweet! Really taking on Mathematica now man! ;D

I definitely can't attest to anyone else, but I WILL be using these!

by kgm

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