Exclude glyphs from customParameters InterpolationWeightY?

Is there a way to exclude certain glyphs from customParameters InterpolationWeightY? Characters which are circles (period, dotaccent, copyright etc.) deform into ovals.

No, That is not possible.

would be good though. As I mentioned, for circles.

Is there a work-around for this?

Not without a big change to the whole interpolation code.

The only way I found is to insert a intermediate and distort the outline, so that the interpolation is correct in the end.

By the way, when a customParameters InterpolationWeightY is included, it has no effect unless I close the glyphs file and reopen it. I think this is a bug.

Secondly, the blue zones don’t get changed accordingly. They are wrong when a customParameters InterpolationWeightY is included.

What do you mean? This works fine for me. The preview is immediately updated with the correctly interpolated instance.

There were some cases that the interpolation would not update. I fixed those.