# Vector Normal? From Orgin?

Hi Fourm,

I was investigating how to Display the Vector normals of a surface. Attached is my clustered Vector Display for a brep, but I had another thought as I was thinking about vectors - how might you retrieve the normal direction of the points from a circle?

Best regards,

Vector Normal Help.gh (9.6 KB)

It will the the tangent vectors + or - 90 degrees. Or you can use perp frames and extract the x or y vector of each plane.

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Hi Michael,

I have the Frames perpendicular to the curve, do you have any idea how I could rotate the frames to face outward?

No need. Deconstruct the plane, then plug the x vector result into a reverse vector component. This will be your normals.

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The Reverse Vector Component Doesnâ€™t output any new frames. If for example, I wanted my Frames to point away from the Crv, rather than perpendicular to it, is there a way to rotate them accordingly?

Best regards!

You just need a vector. Why do you need the frame if the goal is to make a normal vector? If you want to rotate the frame then there are many rotation components. If you want to flip the plane there is a flip plane component. But again, if you just need a vector then you just need to get the planes x vectors and reverse them.

You can use Derivatives and you Get 4 vectors

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Why donâ€™t you just use the â€ścurvatureâ€ť-component? It gives you the curvature vector at a specific point on a curve.
Just be aware that it doesnâ€™t work on linear curves

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Curvature tends to flip along the curve based on curve direction (concave / convex), for a circle it is fine.

Derivatives works in the case of a circle but not a free form curve for normal, in this case it works.

See here some comparison where:
Perp Frames (Green) will go all inward or all outward because they are zero-twisting).
Curvature (Blue) is sometimes in the other direction based on curvature concavity or convexity.
Derivatives (Red with labels) wonâ€™t find this normal.

Compare.gh (12.4 KB)

Anyway, they all work for pure circles, just some info to be aware of.

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I create this python component to find perpendicular lines (and other vectors) with flip direction option on different curves, it will appear in Curve >> Division

New Divide.ghpy (32.5 KB)

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I suppose this exercise helped me do this in 3D on a surface, this was something I tried (kind of works). Iâ€™m sure there is a better way to do this - or control objectâ€™s rotation based on itâ€™s normals vs. the normals from the points.

I used perp frames to orient objects from the normals.OrientObjectbyNormal.gh (211.4 KB)