The current setup for Sean used an Elongated Box setup. This setup worked but had been tricky to use for players to get around tight spaces.
I've experimented with a couple of different setups and script versions until I got the behaviour working the way I had in mind. Sean is now using a Complex AI Collider setup which allows her to Weasel around corners easily while doing body bending.
The end result is now a much better experience for players and allows them to weasel around indoor areas and winding spaces easily. There will be a couple of situations where Sean will be the only one able to enter certain spaces. So think twice if the path ahead is the only one you can use to solve a situation. Your Partner could be able to open up completely new path.
The video below contains 3 sections. The first one shows how the setup works. The second and third one is an artificial dragon parcour I've set up in a generated room to test the setup.
Next time around I'll be really talking about generation scripts, promised :D
It's mind-boggling how you got all this working on a custom from-scratch engine. Fantastic job my friend!
Actually it's possible because I've made an engine flexible and powerful enough to do this without source code access required.