Can’t convert to compatible TrueType curves. Glyph “A” is not compatible

Hi, I’ve seen this post a few times but not quite the same issue.
I’m testing using live strokes for variable font, and have two axes, weight and width.
I’ve been exporting this as a GX successfully and just decided to try and add a Thin weight to the masters and instances by duplicating the regular master and changing the stroke and instances info accordingly. So the letters are duplicates of each other.
It’s super simple, the A only has two lines so it’s clear that the masters are all compatible, and the preview is rendering correctly at the bottom of the window.
But on export I get the error “Can’t convert to compatible TrueType curves.
Glyph “A” is not compatible.”
I have Enforce Compatibility Check on in the custom parameters.
Can anyone think why this is happening?

that happens when the conversion to Truetype fails. Can you send me your test file?

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Thanks Georg, sent to support@ FAO Georg

If you enable View menu > Show Nodes > Extra Nodes, You’ll see that in some masters there are no extreme points at the feet of the A. Inserting them would produce a small bump – but not doing it breaks compatibly. I need to think about this.

Thanks Georg

Hey Georg
I looked at the nodes on the strokes and it seems like the amount of nodes reduces as the stroke weight gets thinner… So the fatter ones have 4 nodes around the feet but the thin weight only has 3. Is that what you mean?

Yes, that is what I mean.

Great, glad I understand. I’m assuming not but is there a way to add extra nodes to parts of a live stroke? Paths>Add extremes isn’t relevant here right?

I am experiencing the exact same problem here. Either straight line or curve, round caps break compatibility. I hope it will get fixed…

You need to explain your problem a bit more.

@GeorgSeifert Hello Georg, I’m wondering how to insert an extreme point when I use stoke weights.

Can you send me that glyph?

Thanks for the file. The algorithm doesn’t produce compatible outlines in a few places. I’ll see what I can do about this. it is mostly about the extreme points in the round paths endings. Some ends have one and some have two.

Hi there
Did you find a solution for the Noods Problem? I Think i’ve got the same issue here…
I have two identical Path Lines just with different stroke with (Regular Master with a stroke of 100, Bold Master with a Stroke of 200).

Otherwise you recommend to convert the strokes into shapes?

I’m having the same issue. Although everything is compatible can’t export as variable font. 3 glyphs have corners like in this screenshot. I can’t delete them because they are vital to prevent kinks.
Screen Shot 2022-11-13 at 19.03.40

Can you show the corner in another master? This kind of construction is (currently) sadly not possible in variable fonts.

I see, Fontmake showed a similar error. I removed this corners and its working right now. Also, in UFO format the masters have different numbers of nodes.

Screen Shot 2022-11-13 at 23.11.43