I’ve had this idea for years and I finally have functional software that I can use with opentoonz!
The idea is to simplify lip synchro-lipsticks, expressions, and head movements when a character speaks.
It is not so important in 4232, but in series type productions, television programs or streaming of high demand, the lip synchro-lip and the expression sheet is what takes a lot of work and to a large extent can be done by the voice actor when recording the dialogue.

In this video you can see how the character imitates the positions of the head and the expression.

Contrary to a classic rotoscope that tries to imitate movement, this one tries to create an “expression sheet” creating less or more animated movements that can be adjusted to the character.