Principle curvature

Is there a way to generate the principle curvature curves of a surface ?

All of them? Only the ones through a specific point?

Yes at specific points especially the ones at the transition of curvature sign.

a very recent post

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Hi @dai_kandeel,

Make a C# script component that calls Surface.CurvatureAt.

Does this help?

– Dale

Thank You for your reply!
It shows an error but I think there is a component in GH SurfaceCurvature makes the same thing, right?
I wonder if I can draw 2 principle curves on the surface at a specific point .

Yes, I believe the Principal Curvature component does as I mentioned.

Can you explain this further?

– Dale

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I drew a point and got the closest point on the surface to get its uv values and then calculated the curvature .
I want to draw 2 curves on the surface at this point follow the curvature of the surface.
I still do not know too why it calculates v as 0 for the point on surface. (15.0 KB)

Using your trimmed surface: (685.3 KB)


A grid of surface points, color coded (green = positive, red = negative), with a choice of C¹ or C² (blue group): (691.4 KB) (DEPRECATED, see version ‘d’ below)

Added magnitude indicators: (696.5 KB)


Thank you so much !