Trying to Rig opening book, Weights not unweighting


Hey there!

I’m doing the training from FXPHD Motion Graphics Production Techniques course and I’m at the part where they are rigging an opening book. They are using an older version of C4D so the weighting tools have changed slightly, he’s using “erase” mode but I believe I should be able to use add(+cntrl)/subtract or absolute(+cntl) modes to get rid of weights which does work but not all the time.

The book is set up to only open one way with 3 joints. First joint starting at the bottom of the spine, Second Joint at the top of the spine, Third joint across the top cover.

When I rotate Joint 1 and 2 to open the book the bottom cover rotates with it because it has 100 weight influence on those joints still for some reason.

If anyone knows why I can’t unweight the third Joint from the back cover let me know, I have attached 3 images to hopefully give you a better understanding of what’s going on.

1.png = blue cover shouldn’t be weighted but I can’t get rid of it
2.png= rotating spine joint and back cover goes with it
3.png= rotating front cover joint makes back cover move with it