FIGURE STRUCTURE / HIERARCHY

The BookStack4 figure has six bones/bodyparts in a chain:

Body > Stack > Book1 > Book2 > Book3 > Book4 > TopOfStack

The first bone/bodypart (Stack) and last (TopOfStack) have no associated geometry and all their parameters are fixed (force limits is set and the minimum/maximum limits are the same) and the dials are hidden. The reason for the 'Stack' bone is explained in post #67 of the HiveWire3D topic (basically the joint parameters are different for the first bone and I couldn't do what I needed) and the reason for the TopOfStack bone in post #66 of the HiveWire3D topic (basically ensures that a nested child stack will respond correctly when the thickness of the top book changes).

The remaining four bones are for the four books. Here's the hierarchy for a single figure:

and four a stack of two figiures, the second being parented to the TopOfStack bone of the first.

---

The 3Dcheapskate* occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.

*also available in ShareCG, DAZ, and HiveWire3D flavours (the DeviantArt and CGBytes flavour have been discontinued).