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


What’s wrong with what you are showing right now? I don’t see any errors. Please be clear about what exactly you need. If necessary provide a diagram…

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.

I think you may be looking for Curve.TangentAtParameter …

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If I understood you correctly, if you get the CoordinateSystem of the curve with the node “Curve.CoordinateSystemAtParameter” and then get it’s axis you’ll have it for each point at the parameter you’ve set (0…1). I am just not sure which axis you should get, but I guess it is XAxis. For this you’ll need to use the node “CoordinateSystem.XAxis” (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 line…which is actually technically wrong since tangent should touch the curve at one point only…just 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 :slight_smile:

All lines (curves for generalisation) have tangents and normals. Even straight lines have tangents; you’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 ‘touch’.

Ps: That wiki link states:

For example, in the two-dimensional case, the normal line to a curve at a given point is the line perpendicular to the tangent line to the curve at the point.