I’m not sure as I’ve never done it myself, but I can think of two approaches:
- Have an animation for the character pre-made and set up the bookshelf and book so they’re positioned and sized perfectly to fit the animation. Before the animation starts, play another one and position the character in the exact spot needed to make the animation fit.
- Still run a position-the-character-in-the-right-spot animation in front of the bookshelf, but then use inverse kinematics to allow more flexibility in how high or far to the side the character can reach for other books. If the book is far enough that it looks weird when animating, then animate moving the character closer first. If the books is too low, then the character’s lower half (blend per bone) crouches. if it’s too high, they stand on tiptoe.
This sounds pretty difficult. I am sure I missed something but I hope you can figure it out or if someone on here knows.