Here's an oldie but a goodie, which may be of interest to browsers-by:
"Across the Great Divide: Making the Leap from 2D to 3D"
http://www.simplisticpictures.com/learn3d.html
Kevin G.
—
[I]Kevin Geiger
Director & Co-founder
The Animation Co-op
http://www.animationcoop.org/[/I]
I like to draw the analogy of working with puppets in balistic gelatin.
It's like 3D puppet animation without all the gravity and electrical and set problems.
The difficulty comes from the fact that you can't reach in and grab it.
No grabbing. But you don't need to use wires and surface gauges to figure out the next pose.... you don't need to flip switches to get particular lighting effects....You don't have to worry about old armature problems, like legs collapsing under the bodies weight or the whole puppet collapsing over.
But like drawn animation, you can make keys and breakdowns and the more you define the spaces, the better the animation.
Happy Trails,
Eric HEdman
animation-story-design-art