Recently I asked Lukas Schneider (https://www.revolvertype.com/)
whether he would be interested to script a small tool in Python that (live) visualizes the construction of cubic Bézier curves in one’s own type design –for educational purposes. I prefer this a little bit more than demonstrating the construction with/on an a more or less arbitrary shape. With such a tool students (and educators) can explore and demonstrate the construction using their own letter forms in their preferred font editor.
I was not surprised that Lukas almost immediately started to script. Not only do I know him as a highly talented and proliﬁc type designer, he has also become a very experienced Python scripter. In the past years we worked together on the LS Cadencer and Cadenculator (https://www.revolvertype.com/tools/)
and also on some proprietary consistency tools for the font production.
The tool in question shows the De Casteljau’s method to construct cubic Bézier curves (one can ﬁnd a lot of information about its origin and the math behind it on the web). Also it can reveal how the resolution of the contour is deﬁned, as shown in the image above.
The De Casteljau
tool is available for RoboFont and Glyphs from Github:https://github.com/luke-snider/de-casteljau/archive/master.ziphttps://github.com/luke-snider/de-casteljau-for-GlyphsApp/archive/master.zip
Installing is simply done by double-clicking on the (unzipped) extension. In Glyphs it should show up as De Casteljau
in the ‘Edit’ menu and in RoboFont under the same name in the ‘Extensions’ menu.