Rigging and Skinning - Animating with Blender: How to Create Short Animations from Start to Finish - page 155

A Final Example of Fixing a Rigging Problem

While the problems you encounter dur-
ing rigging are too numerous to mention
in a single chapter (or even a single vol-
ume of a topic), I would like to present
you with one problem that I ran into and
show how I fi xed it. This is very typical
of the kinds of things you will run into,
and the framework for fi nding a solution
should be instructive.

In one of the shots of The Beast , the
mother kneels on the ground to pick up
the little fellow. In her kneeling position
(okay, technically it's a squat, but she's a
dignifi ed lady, so I won't say she was doing
that), the stomach area deforms poorly,
reducing her front-to-back depth to some-
thing like a few inches in real scale. The
effect is highlighted in Figure 9.48. Test
renders confi rmed that it would indeed be
visible in the fi nal product. I needed a way
to prevent the stomach from collapsing like
that when she bends at the middle.

Figure 9.48 The mother kneeling

One of the rigger's best friends when solv-
ing problems like this is the StretchTo
constraint. “Stretchy bones,” as I call them,
are great at adding structure to a rig.
Usually their root is placed wherever you
would like to anchor the deformation, and
the tip is placed on a controlling bone. In
this case, a new bone was added with its
root near the front of the lower abdomen,
about where a belt buckle would be. The
tip of the bone was placed at the tip of the
sternum. Figure 9.49 shows the new bone
in place. Notice that, as I was attempting
to solidify the structure of the abdomen,
the bone approximates the location of the
abdominal muscles.

Figure 9.49 A new bone is added to help control abdominal deformations