# Create a vector a long line

Hi all,

i have these series of curves and i want to create a vectors along these curves in order to be able to create a circle based on that vector which will be a normal vector for circles

Thanks

Whatâs wrong with what you are showing right now? I donât see any errors. Please be clear about what exactly you need. If necessary provide a diagramâŚ

is there a node can give the normal vector along a specific line?

Normal is a vector that is perpendicular to a surface. There is no such thing as line normal. https://en.wikipedia.org/wiki/Normal_(geometry)

I think you may be looking for Curve.TangentAtParameter âŚ

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If I understood you correctly, if you get the CoordinateSystem of the curve with the node âCurve.CoordinateSystemAtParameterâ and then get itâs axis youâll have it for each point at the parameter youâve set (0âŚ1). I am just not sure which axis you should get, but I guess it is XAxis. For this youâll need to use the node âCoordinateSystem.XAxisâ (or YAxis/ZAxis)

@Andreas_Dieckmann I might be wrong but there is no tangent to a line. OP has a polyline in that image. Any tangent line will return a line that is equal to the input lineâŚwhich is actually technically wrong since tangent should touch the curve at one point onlyâŚjust saying.

@ricardoperucci yeah, I think you are right. I have no clue what the OP wants, but I can guess that he wants a perpendicular plane or a Coordinate System at line, and then extracting X axis from it, which would be a line perpendicular to an input line. There is no guarantee as to direction of such line which would be dependant on input line direction itself.

Haha @Konrad_K_Sobon, should have worn my glasses

All lines (curves for generalisation) have tangents and normals. Even straight lines have tangents; youâre right that the vector is the line itself (colinear), however tangents are defined from a parameter on the curve and an algebraic expression, not by what they âtouchâ.