Path Incompatibility in variable font – only when exported

Hey guys. I have a 16-master font file (currently with a single glyph, /E, for testing purposes). (If 16 masters sounds excessive, I’d love to hear suggestions for minimising the number of masters!). I have 4 axes; weight, contrast, slant and bell (see: bell bottom scripts, such as Brandyscript.)

My paths in the Glyphs Edit view appear to be compatible in every way. Path direction, shape order, number and type of nodes, etc. All instances/interpolations work correctly in the Instance Preview window in Glyphs. The issue arises in Illustrator (and AxisPraxis etc. Anywhere after the font is exported).

Any slider combinations when sticking to Weight: [0] (Thin) work well. However, the closer I get to Weight: [100] (Black), the more jumbled the paths become (as shown below):

When turning on “Show Master Compatibility”, you can see that some path segments get highlighted yellow, whilst some are green (I recorded a quick screen recording to demonstrate). I have meticulously ensured that everything is compatible, so I’m not sure what else to do, or how to know what Glyphs is telling me with the yellow paths.

Screen recording:

Any suggestions? Thanks :pray:

Here is my .glyphs file: (8.7 KB)


You have 4 axes? There is a problem in Glyphs when you have a maters for all slider at max. I’m working on it.

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No probs, thanks!

Just to be clear, (though I’m sure you got this) the problem only exhibits itself outside of Glyphs, from the exported .ttf file, in use in Illustrator/Axis Praxis etc. The interpolation, even with all sliders (value boxes in the Instances tab) maxed out, happens correctly inside of Glyphs.

Glyphs uses a different interpolation mechanism. There is a problem with generating the deltas (that is how the different masters are stored in a variable font).

Ah I see. Thanks for the info. No rush of course, but do you think this fix will be available in the next update?