The behavior of the granny and associated family of knots are a great example of the role of directional friction and twist in knots.
Despite looking almost identical, the square knot is a fairly good secure knot, while the grief knot is about as insecure as a knot can get, and comes apart with even the slightest movement.
I find this ‘constructive cogging’ effect fascinating.
So I am interested in developing some friction for this, as I’ve never really seen the phenomenon simulated before except by making a complex mesh of the rope as a solid. The torsion resistance is possible with the beam elements, but the directional friction would require adding something new (and I think it would also need a distinction between static and dynamic friction).