A double overlap can’t be used to cut out counter shapes.
You can try to us it as a mask (set in the lower sidebar panel; but make the path counter clock wise).
I make the path of component as counter clock wise and not set as mask. And set the component inside the actual letter size as mask. And I made sure the component is on the top layer. But the error message [Can’t convert to compatible TrueType curves. Glyph ‘E’ is not compatible.] pops up when I try export. Don’t know if I misunderstand.
I think the mask outlines is compatible since there wasn’t any error message and red highlight regarding to the component. Please check my project file and by the way I did all my testing on the E letter. New Font_Mask_Test.glyphs (128.6 KB)
Using the methods mentioned above, when I export the font, most letters containing this component would trigger the error [Can’t convert to compatible TrueType curves.].
However, the key point is that each time I export, random letters would not trigger this error while others do randomly without doing anything and just export 1sec later.
Everything is like randomly good to go and the next sec it doesn’t.
The Star components overlap in the Regular1 and 3 (not a great master names, pick something more descriptive). The “masks” will kind of apply a remove overlap and so you get quite different path structure.
I played around a bit and cap components are probably a better choice. Have a look at the “E” and “F”. New Font_Mask_Test gs.glyphs (131.0 KB)
It doesn’t fix the overlap issue. You need an alternate glyph for this.