The chest looks better with the sternum rotated, but will it still look OK without the rotation? Let's test.

That'll work. What about a full backward stretch with rotations at both the base of the spine and at the sternum? You need to examine a full body view to see if it's working. Both front -

and back.

We can live with this. But we must also try the opposite bend in which the head, the sternum and the spine are all rotated forward. This requires moving the hips first to keep the character's balance. A number of minor vertex weighting tweaks are need to get a passable result. It's far from perfect, but further adjustments to suit this pose will certainly damage what we've already got.

This has been a serious lesson. Character setup can never be taught as a "paint-by-numbers" tutorial. One can only teach an attitude and a discipline because, after all, this is an artistic endeavor. Your results can never be perfect. Even if you have unlimited time to work on a setup, you will reach stages in which you are forced to make compromises.

The key is a willingness to work methodically, from larger regions to smaller ones. You must develop a feel for how bones work together, and be willing to test every adjustment you make in all directions, both locally and in the context of larger rotations.

We'll finish up with the arms and legs next time.