It’s not really possible to pin a side of the surface to the spine, I think. I have done page curls with the deform node in action, but it only worked for simple things like a page curl or sticker labeling sort of things, for me.
I had had an alembic from the 3D department once that I could import into action but it’s long lost now.
Its setup using a page curl i made a few years back for a page being ripped off, but it found if it animate the end point of the deform animation to line up exactly with the edge of the page, and have a slight rotation at the start then i get the exact look i was hoping for.
Now i just need to figure out the number of pages to put in the book!
That’s a trick I tried (and failed). The important thing was to keep the page from stretching while I was doing the deform animation. I had ex-bicubics as well so maybe that further complicated my setup.
This makes me wish for Houdini Engine in Flame. They already have such a thing for Unreal Engine where the Houdini artist creates a setup and exposes parameters for realtime interaction in Unreal Engine.