Differents interpolation between Statics and Variable files


I have a problem with the matching of the interpolation between the static and variable files. Currently I have matched the Axis Location parameter on all my Masters (3 upright, 2 italic) and on all my instances (9 upright, 9 italic). On some letters the interpolation is not linear and I have not done anything to get them otherwise. On the variable instance I tried to add an Axis Mappings but it did not change anything. The most problematic is on the Italic version. The horizontal of the ‘T’ doesn’t seem to bend until 700/1000 which also affects the spacing. On some letters like ‘B’ or ‘R’ even though the weight doesn’t seem to match, but the tilt seems to work. (On my capture in black the static file, in red the variable file).

I did not find a corresponding topic on the forum.
Does anyone know where this can come from?

Thanks a lot

Hi, which version are you using? In 3.2, try going to Font Info > Other and setting the font type to Variable. This should eliminate any interpolation discrepancies.

Hi thank you for your reply!
I’m on 3.1.2 and this seems to be the last update available to me.
In Font Infos - Other, I don’t have anything related to the variable…

You can enable beta versions by going to Preferences > Updates > Show cutting edge versions.

Note: Glyphs 3.2 is still very buggy, I recommend you keep one application called Glyphs 3.app (your current app) and a separate one called Glyphs 3.2.app in your Applications folder. You can download a separate Glyphs 3.2 app from this link (rename it to Glyphs 3.2 and move it to your Applications folder): https://updates.glyphsapp.com/Glyphs3.2-3175.zip

I did the update and set the font type to Variable but nothing changes… (except that it reveals a compatibility problem :slight_smile: )

How are you testing your exports?

On Adobe Illustrator and Indesign

Are you using the Adobe Fonts folder? Are you sure your updated exports are being read correctly by Ai and Id?

I install them directly in the font library by deleting the latest versions and restarting the software. I’m going to do a test this way.
Thank you

That won’t be enough. If you use Adobe software, it’s best to use the method I linked above, it is the only really reliable method of testing in Adobe apps. No app restarts required.

Thank you! I will test this method


I was able to create the Adobe file as explained, deleted the file from my font library so as not to create a conflict, but nothing changes.
I also created an HTML/CSS file to see if it was only from Adobe, but there is the same lag on the browser (chrome).

In that case, I’m afraid I cannot help any further. Georg or Rainer might be able to help, but from what I understood, in 3.2 this exact setting exists for the sole purpose of guaranteeing identical interpolation.

Have you tried removing the Axis Mappings custom parameter? Axis Locations should be the only method you use nowadays.

Yes I removed the Axis Mappings…
Thank you very much for your help, if I find a solution, or even if I understand why this effect exists, I will put it here.

Hi all,

Thanks for your input, @SCarewe. I just wanted to let you know that the reason for the differing angles in the stem and crossbar ends of the italic T were due to the font having a 5-master setup with the following masters:

  • Thin
  • Regular
  • Extrabold
  • Thin Italic
  • Extrabold Italic

As you can see, the regular-weight italic was missing. As I’m sure you can remember, Glyphs doesn’t handle such configurations well when generating the deltas in the variable exports, even though the static exports are fine.

This makes sense. Since the master between the two italics does not exist, the variable had to find a match. So we need to have the same number of masters for each axis. I understand better what happened now.

@tamirhassan @SCarewe thanks for your time.