Interpolation Problems – Dekink


I’ve got a problem with the interpolation in the version 1218. I’ve got a six masters setup. Instances are made in 5 widths and 10 weights. For the most part all instances look good and I’ve started adding additional masters for individual glyphs (the Brace Trick). The problem appears when i tried to fix the appearance of the number 2.

Here’s how it looks, I’ve marked the problems:

When I add a master to fix the Condensed Thin instance, the problem on the Condensed Regular instance remains:

Then I add another individual master, and this happens:

If I turn off the CondThin individual master things look better, but the problem with the CondThin instance returns:

Any ideas what’s going on? I’ve tried the 1075 version and it doesn’t make this problem, but I really wouldn’t want to go back to old versions. I’ve checked all 6 masters and there are no kinks anywhere and the paths are compatible.


Adding new masters will not fix this. This is a kink. They usually appear where two curves connect diagonally. but also when a diagonal line and a curve connect. The proportions of the diagonal line and the tangent handle need to be the same in all masters.


I’m not sure I understand this. Do you mean (for example) if in one master the line is 10 points long and the tangent handle is 6 points long, in another master if the line is 20 points long, the tangent should be 12?


Yes. Or keep the angle in sync.


See the MM tutorial about ‘keeping your outline compatible.’


OK, although I’ve been using the dekink script many times I obviously did not understand fully how it works. Thank you @GeorgSeifert and @mekkablue, now I get it. And the MM tutorial explains it perfectly. Although I read it more than once in the past couple of years, this bit of information about keeping things proportional somehow eluded me.


If it is static fonts you are exporting, you could add the RMX Dekink Only function as custom parameter. Very short handles and segments will always be problematic though.


I know that, but I prefer to have full control of the final shape. Turning on that custom parameter kinda feels like “hey I can’t solve this problem but let’s click the auto button and hope for the best”. :grin:


The outcome of the parameter is predictable and verifiable. You can double check the resulting shape in the preview area, so you do not give up control over your shape. I would give it a try.