Dog riggin'

The great thing about rigging is that there isn't a right or wrong way to do it. In the end, a rig must satisfy a small list of requirements:
1. It must be fast.
2. It must be easy to use.
3. It must reach the needs of the scene.
and for an extra bit of fun
4. It must avoid gimbal lock.

When I was in college my instructor would show us examples of characters where the hands and face controls would be set driven keys. If it works for the scene, then there's no problem. I don't agree with this method, but it's not wrong. I prefer to not limit a rig by a min- and max- value. The problem with animators is that they like to push things beyond what is expected. What if, in some particular scene, the pose of the hand at its maximum finger travel didn't look right--the silhouette doesn't read. What if you needed to push that pose further to anticipate a really wild take? Oh....set driven key...."call the tech person and have him adjust the rig so I can get this pose!" Nah. That's not gonna get you invited on the next project.
I digress. Personal pet peeve about SDK's.

Today's bit of work involves another character I am not at liberty to share because I don't have the permissions to show copyrighted material. Sucks, I know. But the geometry can be anything, really. It's a small quadruped. On most mammals, the center of gravity is in the belly. On a person the belly is right above the pelvis, so it's a nice place to put the root joint in a rig. In a four legged creature, though it's different. Standing on four hooves, paws, or claws, you can lift any one leg and essentially become a tripod, you can wiggle your butt independent of your upper body, and you can wiggle your upper body independant of your bottom. You can sit on your haunches, and when you run you bend and twist and heave in some really interesting ways. The pivot for those actions is right in the belly area. Watching Gizmo here, it's interesting to notice where his stomach is. If you could put a tracker on his side, just in front of his hip, you'd notice that his vertical translation is quite steady. The same is noticeable on larger animals, such as Pudge. A slight sine wave pattern, yes, but in relation to the rest of his body it's practically static. This is a small dog's center of gravity, and an idea spot for a root joint.
The center, low joint is the root of this very unfinished rig. This will allow the animator (which will probably be me) to create a realistic walk cycle, sit, tail wag (which in small excited dogs ends up wiggling the entire butt), bend the forepart of the body down to retrieve objects and other such little doggie actions.

I think the next blog entry will be about those feet....but until then...