# Segmenting a ring into three pieces in Inkscape

I‘m trying to re-create these shapes in Inkscape, namely the white lines:

I could trace this image, but I'd like to know if there's a clever, and more accurate, way for re-creating the shapes.

For context, it’s for a capacitive touch wheel design (page 40).

I will explain how to make one central element. The rest ist straightforward, I hope.

1. Create three concentric circles with equal differences between their diameters (e.g., 200, 250 and 300).

2. Create a vertical line that is as least as long as the biggest circle’s diameter.

3. Centre that line on the circles.

4. Duplicate that line and rotate it by 120 °. You should now have something like this:

5. Create a spiral (F9); size and position do not matter.

6. Set the spiral’s parameters as follows: turns: 2.0; divergence: 0.0; inner radius: 0.0. It should now look like a circle.

7. Paste the biggest cirle’s size to the spiral and center the spiral on this circle. The spiral should now run along the outer border of that circle.

8. Set the spiral’s divergence parameter to some value that allows you to see it’s features. Now adjust the turns such that the spiral starts at the top of your circle (marked by one black line). Then adjust the divergence such that the spiral’s intersection with the other black line is just on the outer border of the middle circle. Finally adjust the inner radius such that the spiral ends shortly after that intersection. The result should look like this:

9. Repeat step 5 to 8 one level of circles lower with a spiral going into the other direction (mirror it):

10. Select your spirals, object to path, combine.

11. Select your straight lines, increase their width radically (say to 50), stroke to path and union. Make sure that the result is in front of the spirals.

12. Select this result and the spirals, cut path.

13. Remove those pieces of your spirals that were covered by the straight lines and combine the rest:

14. Edit paths by nodes, select the appropriate endpoints and join selected endnodes with a new segment:

• Thanks. I'm fairly advanced with Inkscape, but this is a great technique I wouldn't have come up with ;) Commented May 13, 2015 at 21:35