Add curve in polilyne 3d with dynamo

hello guys

i have a 3D polyligne that i got points from this polyligne by dynamo (see the first picture), now i want to realize curves with these points, (see the second picture red line on Z plan ). is it possible ?

thank you for you help


hi @dr.hybride,

This is very well possible with Dynamo!
Could you maybe in depth explain how you want these curves to look? What are the input parameters for these curves?

If you want a straight line you can use the Line.ByStartandEndpoint node.


thank you for you help

attached an other picture for more explanations. for help to creat this curve or line i can to creat a line with known lenght at the middle of two points, but i dont know how?

Hi @dr.hybride,

You could create a local coordinatesystem at the 0.5 parameter of each line and then place a point at the left or right at the desired distance, now you have for each curve a startpoint, midpoint and endpoint and you can create an arc by three points :slight_smile:

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Assuming you have the curves from the polyline in Dynamo already:

  1. Polycurve.Curves
  2. Curve.PointAtParameter where the curves are the curve input, set to @L1, and the parameter is a list defined as 0, 0.4, and 1 (a code block of 0…1…#3 will work).
  3. Geometry.Translate to move the sublists of points by the desired distances down. Distances should be three values in a list, woth the first and last number being the same (ie: [0,3,0];). Be sure to set both lists to @L2 so that things move correctly.
  4. Use an Arc.ByBestFit node to draw the arc.
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thank you very much but i am bloked for placing the point left or right at the desired distance, attached the pitcure where i stopped , how is called the node ?
thank you

@dr.hybride is this what you are looking for?


yes, very good job thank you very much,
can you take a picture of whole dynamo screen please ?
just an other question, can we change independently the diameter’s curve ? it will be perfect.


You could input a list of distances for the offset distance


@dr.hybride here is the script.

Arcs.dyn (23.5 KB)


i don’t know how much i can thank you.
it’s perfect
just a other question,can we change independently the diameter’s curve?

Do this.

So instead of a single number slider for the Point.ByCartesianCoordinates node, create a list of diameters that you want. The list will need to have the same number of indices as the number of arcs you are creating. So if you have 2 arcs and want to have diameters of 5 and 10, then it would be a simple code block with this:


That’s just one approach - there are many ways to make a list of numbers :slight_smile:

thank you very much
you are the best.

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