Align curve on TWO curves

Hello guys,

I would like to align a polygon curve alongside TWO other curves. Unfortunately there is only a command to align and clone the shape on ONE curve. My goal is that the polygon curve would rotate/ interpolate and align with the blue and the green curve (see second image).

How is this possible? Is there a plugin for this?
Sorry to bother you, I’m just starting to learn Rhino.


I think I follow what you’re looking for but correct me if I misunderstand. Do you want to have the ends of the white polylines touch the green and blue curves? Can you post the 3dm file as well? I have some ideas but don’t want to lead you down the wrong path if the geometry is actually different than what I think it is.

Hi Brian

I want the end of the white polyline to touch only the green line, but go through the blue curve (it can go beyond or stop before the blue line).

One Idea I had was to first align the white polyline on the green curve. And afterwards iterate and interpolate each copied polyline to align with the blue one or blend between several manually aligned items.

I have attached the file for you.

Does this work for you? I lofted a surface (Loft) between the green and blue curves and then used the Pull command to pull the polylines to it. The kinks in the surface cause some division for any curve that hits those areas. For those issues, I’d probably use CageEdit instead of Pull with a line as the control object drawn between the ends of the zig zag polyline in that area, then adjust the straight line control object’s end point to a Near Osnap on the blue line. alignment problem_bjames.3dm (203.4 KB)

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Hi Johannes - see if this quick & dirty Python script helps - use RunPythonScript or -RunPythonScript “Path to py file”. The script assumes, for now, that the curve direction of the polylines points from the first reference curve (green in this case) towards the second reference curve. (1.1 KB)


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Thank you so much Brian! This methods works great.

Also thanks to Pascal. The script works great for the alignment of a single polyline to the two curves.

@J3D - this one will do all of the curves at once. Pre-selection should work, for the curves to move. (1.2 KB)


Thank you! This is also a great introduction to Python :relaxed: