Line tangent to end of Bezier curve

Using Grasshopper, I am able to extend a tangent line from the end of a simple Bezier curve. When I move the control points for the Bezier, the linear extension remains tangent. When I try to achieve the same thing directly in Rhino, the linear extension does not remain tangent when control points for the Bezier are moved. I have tried creating the extension in different ways, in this case Curve > Extend Curve > By Line. I note the 4 control points on the line segment and have tried to edit those without success.Tangent Line Extension.3dm (2.5 MB) Tangent Line (4.4 KB)

Hello - In Rhino, make a line in approximately the right place. Run Match with history enabled and match for tangency, with ‘match other end’ set to None.

Does that do it?


Hi Pascal -

Result is the same. Line still has those 4 control points and does not move with changes to the Bezier.


Hi Kevin - make sure not to set the Join checkbox in Match.

LineTangent.3dm (31.8 KB)


With your Control Point curve this works, but I need to use a Bezier/Handle curve and that does not work?

Hm - I guess I need an example - a curve is a curve once it is made, it does not really care how it was made - if you set up Match as I described, editing the curve should keep the line tangent…


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I guess I did not appreciate that about curves since Rhino provides multiple ways to create them, e.g., Control Point, Handle, etc. This will work fine for me now that I understand this. Many thanks!

Cheers - Kevin