Is it possible to split a curve in two?

I’m trying to draw a curve and split it at a given point. Is this possible with the existing tools?

I’d like to draw a curve, split it at a point, translate the second curve (e.g. 1.5 along +x axis) to insert a dart. The end result that I want is a the original continuous curve when the dart is folded out.

Would love any tips, including doing this type of dart insertion / seam trueing a different way.

If curve name is Spl_A1_A2, then:

Use one of the Segment curve tools, (Segment Simple Curve, etc.) depending on the type of curve, and select Spl_A1_A2.

To split at the the midpoint, enter this formula: Spl_A1_A2 / 2

More complicated example: To split the curve 7% past the midpoint: 1.07 * (Spl_A1_A2/2)


I am not quite sure what you want to do; but it is possible to insert a point into a curve and then move or flip that curve including that point; later on you can just take a part of the curve in your detail:

You have a frame with the curve and the point where you want to split the curve (here A5)

  1. click point intersect axis tool

  2. click on the curve, then on your point (here A5)

  3. select the angle the axis should have

Then you can move or flip or rotate the curve including the new point on the axis; here I took the move-tool:

  1. click move-tool

  2. select every point you want to include (here A, A4, A6 and A3) and the curve, press ctrl while selecting

  3. confirm with enter

  4. move for desired length and angle

The features change frequently; I think I have the build of 17. Nov of Version 0.6, I had shortly opened the repository after the encounter with the lengths again, unfortunately. There might be a new build out with different features as new versions come about every week - if you have the newest build you’d need to look and try if there is a differenc, sorry I can’t help you in that case.

You can also flip curves and points and rotate them, just play around with the tools :slight_smile: (maybe you do that in an extra file, not in your serious pattern).

edit slspencer was faster and gave you probably what you needed :slight_smile:

1 Like

@slspencer, @moniaqua many thanks for your quick reply! I understand the tool that lets you create a point along a curve. It’s pretty neat. However, i’m wondering if it’s possible to do is something like this:


In other words, is it possible to take an existing curve and split it apart by creating two equivalent curves (ostensibly with new control points)?

I tried to sketch out what i’m trying to do, in case it helps. The ultimate goal here is to make sure the resultant curve is smooth when the dart is folded out.

If it’s not possible to split curves, is the best way to get this effect as @moniaqua suggested — by translating the curve and then selecting the relevant points as necessary in the detail view? If so, how do you keep the draft from becoming cluttered with unnecessary lines?

I just tried it with the segment-tool, but if you move objects you will move the whole curve, not only a part of it.

Use the group-tool.


The whole thing with all groups visible:


And just one group invisible:


And, no, afik a group can not be moved or rotated at the moment :wink: But you still can select the points and objects of a group again to move them…

1 Like

Thanks! for these tips! super helpful.

At the moment, we have to suffer with the unnecessary lines.

@slspencer makes sense!

I found the suggestion of using groups to control the visibility of “extra” lines a great idea for what I need to do. Thanks @moniaqua

I successfully used the split curve tool on a simple curve the other day but for the life of me I cannot get it to work again. After i create the simple curve and then change to the segment curve tool i cannot click on the curve to segment it. Is this a known issue or am I doing something wrong? (screencap below)

Use the ‘Segment a simple curve’ tool: image


Group the lines… curves, etc and tun off their visibility.

1 Like

Dear community

I use the “segment a simple curve” quite often in order to mark “passmarks” or notches in the detail mode. my current issue with the tool is that the curve in detail mode will be interrupted when i divide it. (mostly i use a formula: spl_xy/z). when i collect the points from my construction i proceed clockwise in the following logic: corner point / curve(clockwise) / segment point / corner the result in detail is the following: corner point-curve-segment point-STRAIGHT LINE INSTEAD OF CURVE-corner point…

see the sreenshot at the segment point a109… 37

how do i avoid this?

Sorry for the rookie question…

1 Like

Hi & welcome @jan

No question is a rookie question and the reply will help you and many others in the future :slight_smile: So thank you for asking :slight_smile:

When selecting a point in the middle of a curve, you need to select the curve, the point and then the curve again, otherwise you will get the curve up to the point and then a straight line after it to the next point.


Since you have already created your detail, you can use the Insert Node tool under the Details tab on the left:


Here is a previous topic on using the Insert Node tool: Make changes to a pattern piece after it's made - #2 by slspencer

If you need any further help, please feel free to ask :slight_smile:

1 Like

thank you so much grace… thought i tried all the options; but not this one…

best jan

1 Like

Thank you Grace. I was trying to figure out a passmark in middle of a curve. This answered the question perfectly. I kept trying to add a node for my passmark but was getting a straight line. You are the best.


see my new youtube video of how to make a front twist dress pattern