Linked metrics are shown as out-of-sync in intermediate layers

I have some intermediate layers in glyphs that have linked metrics. In these layers the linked metrics shown as out-of-sync in the intermediate layers, because the metrics are interpolated.

This means I manually have to go into each layer, right-click the intermediate layer one-by-one, and choose Re-interpolate metrics. If I Update metrics for all layers the intermediate layers with be set with incorrect non-interpolated metrics.

This issue results in having a Glyphs file with several blue triangles with exclamation marks, and I can’t know for sure if the metrics are correct or not.

What I’d like to happen is that the linked metrics for intermediate layers are interpolated when I select a glyph and execute Update metrics for all layers.

“Update metrics for all masters” works correctly for me.

Am I misunderstanding it here?

  1. The interpolated metrics suppose to mean the correctly interpolated metrics for the coordinates of the intermediate layer – right?

If that is true, then I select the layer and select ‘Re-interpolate metrics’ to get the correct metrics on the layer.

Then I get this:

where the metrics are red because they are out of sync with the master. Updating the metrics:

Gives me:

With sidebearings that are incorrect for this designspace coordinate.

No. The metrics keys take the values form the linked to glyph at that design space location.

You are being ambivalent here.

Let me try to put it in other terms. In which case will I get the correct metrics for an intermediate layer?

  1. By selecting a glyph containing intermediate layers, and then executing ‘Update metrics for all masters’.
  2. By selecting each intermediate layer and executing ‘Re-interpolate metrics’.

If (1) is the correct answer, then what does ‘Re-interpolate metrics’ do? I can’t find anything about it in neither handbook nor your website.

“Re-interpolate Metrics” re-interpolates the metrics. It calculates the metrics based off the closest (intermediate) masters. This might result in different values than the ones obtained through a metrics key.

To update the metrics, click Update Metrics.

Clear as mud.

One of the two is wrong since both ways interpolate the metrics and yield different values.

“Update Metrics” doesn’t (shouldn’t) interpolate metrics. It does the same as clicking on the red arrows for out-of-sync metrics. What is maybe confusing you is that “for all Masters” doesn’t apply to intermediate layers (as these aren’t masters). You need to do those manually, or via a script:

for layer in Layer.parent.layers:
    if layer.isSpecialLayer():

Right. You helped me figure this out, thank you.

Interpolate: Interpolates between the glyph layers of the glyph I’m editing.
Linked metrics: Also interpolates, but between the glyph layers of the ‘master’ glyph.