Curve tool with a fixed length


Hello, It would be nice to have a “Simple curve” tool with one fixed point and a fixed length to create a seam with two pieces of the same length. Perhaps the tool need a line or axis for the calculation of the sencond point.

Force length of a spline to be equal to x?

Hi @bernt, yes, that would be great :slight_smile: but the simple curve is created with handles that determine the depth and direction of the curve and, therefore, changes the length of the curve-line, so a line or axis wouldn’t help. One would have to constrain the handles to some sort of norm which would remove the magic of creating your own curves. I’ve thought and thought… I just can’t see how this can be done.

Here I’ve created a simple curve and a line that is the length of the curve: Curve-Line.val (1.1 KB)

As you can see that by playing with the handles of the curve, the line gets shorter or longer. So this would work if you were trying to add a flare effect to a seam, but it wouldn’t work in the case of a bra cup… Unless one created it with an arc… because with an arc, the handles are proportionate to the full circle and can be portioned off.

Eeeu! Like I said, I’ve thought and thought. :slight_smile:


Hi @Grace, I know this is not an easy task … :wink:

In my pattern I use a calculated point with the difference of the curves that should have the same length. (armscye)


Yes, one needs to find a ‘very simple’ yet ‘very scientific, mathematical way’ to do this that can be translated into C++ and will work in all situations without having to create a bunch of nodes to work from. And I’m afraid, my little pea-brain just can’t see the big picture of how to do this.

Perhaps you can explain (in detail with pictures) exactly how you do this - including an example. Then we can figure it out and perhaps one of the programmers will come up with something. :star_struck:


Please continue this discussion on

THIS thread. There is clearly a need for a tool that is will support what one could do by laying a french curve or other tool on the paper to draw or measure and create a point. If anyone can post diagrams or instructions about the manual methods they use that will be helpful in designing such a tool.

thank you