Offset Curves Problem

Hi Everyone,

I am trying to offset curves perpendicular to a complex shape geometry. Unfortunately, I might not using the right process because the curves are offset in the XY plan, not perpendicular to the surface.

Anyone for some help?


Rémy (218.7 KB)

You can use offset surface and pull curve


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Or offset the curve points along the surface normals and rebuild the curves when you are done.



This is perfect!

Thank you guys!

@seghierkhaled @diff-arch :+1:

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OffsetNormal would be command to use in Rhino. It directly offsets a curve on a surface in the direction normal to the surface.

This would be a perfect addition to Pufferfish

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I try to refrain from solutions like this in Pufferfish, not that it doesn’t get the job done but, it is not true to what it should be any time you have to interpolate a new curve via control points you lose accuracy in knots compared to the original (even if it’s a small degree). It should be like my tweens which use nurbs math as opposed to control point or division point interpolation to keep high precision. If the command exists in Rhino as OffsetNormal then maybe @dale can expose it in rhinocommon so it can become a gh component. This way we can always trust the results.


isnt it this one?

Seems so. There you go, just toss it into c# script component, but it says there it may not be accurate.

I guess that Rhino’s “Fin” command is quite similar except it produces a surface.

There may not be an exact NURBS curve for the offset of a NURBS curve normal to a NURBS surface. Also note that a curve on a surface of a NURBS surface my not be an exact NURBS curve, and correspondingly a NURBS curve which is considered to be on a NURBS surface may not lie exactly on that surface.