Screen recording of the Split Face sliders in Illustrator (placeholder)
How it works
A line at the chosen angle divides the face into two parts and the second part is repainted in its own colour. Ridges turn the line into a zigzag or wave whose true trough-to-peak height stays equal to Ridge size at every roundness. The gap is a band along the line that can be filled or cut straight through the 3D walls.
What you can adjust
Part 2 colourNone / TC1 / TC2 / Black / White / spot; default Black
Gap fillon/off, with its own colour; off cuts the band through the extrusion
Still live text
Split Face is applied as an Illustrator live effect, so the text stays editable. Change the word, the font, or any slider afterwards, and save the result as a Graphic Style to reuse it.