The Axes you define overwrite the axes names in the masters. So if you have Weight and Optical Size, you need to put the optical size interpolation in the Width fields.
Thanks!
But now as I try to remove the values from the Custom Field (I had a third Axis) I get an error message: The value cannot be empty.
This happens both on the masters and on the instances.
Same here, the second slider does not work.
By the way, will Glyphs be able to export CFF-based variabele fonts? Any particular reason to only do TTF for now?
There is a bug that the default master needs have the smallest axis value. @Natanael, set your optical size masters to 200 (instead of zero) and it will work. I’ll fix this.