The strangest thing…I would have thought that the 1st Radius would be in the 1st Angle direction and the 2nd Radius would be in the 2nd Angle direction - which is how it worked on the back armhole curve. But the diameter lengths are switching around:

I’ve tried changing the Angle at the bottom, but that only turns my curve around the centre point.

If I switch the 2 Radius formulas, then it works fine:

Duh! ok, I figured it out… The Ellipse is always drawn from 0 degrees all the way around to 360. And it’s only the Line of the Ellipse that is drawn from the one angle to the other.

I’m going to leave this on here in the How to… section so that others may find it

Then, the first radius value should have the decription "Radius at 0°/180° "
and the second radius should have the description "Radius at 90°/270° ".
A simple find-and-replace patch should do this …

The Ellipse is drawn from Rotation angle to Rotation angle, the Line/visible portion of the Ellipse is drawn from the First angleusing the Rotation angle as the zero point to the Second anglein relation to the Rotation angle.

So, in the given example, if the Rotation angle had been set to AngleLine_z8_A17 then Radius one would be Line_z8_A17, First angle would be 0° (or AngleLine_z8_A17-AngleLine_z8_A17) since it would be the same as the Rotation angle, Radius two would be Line_A15_z8, & Second angle would be 45° (or AngleLine_A15_z8-AngleLine_z8_A17)

This is one of those rare occurrences where 0° can be somewhere besides “+X”

Hi and nice to see you here, @bernt. Yes, I figured it out but put left it here so that others will find it if they have the same problem.

Yes, you can move the 0° at the bottom Rotation Angle. In which case, 0° can be wherever you want it to be, which will slant the ellipse on its axis accordingly.

I’ve been experimenting with it to do the armhole curves, but I’m afraid I’ll need a few other tools to work with it.