These blog posts will be getting shorter from now on as the deadline looms… they will probably be more frequent though.
Yesterday and this morning I have been rigging. The first was the nuclear pore rig, tedious but relatively straightforward, the most complicated control being a “move arm” set driven key to speed up animation.
The mRNA rig was more of a challenge and much more interesting. I initially followed a DT tutorial for a snake rig using an IK Spline, but it was really hard to smooth the weights in a way that would get the sinuous look that I wanted. So I tried a Wire Deformer, which was nice and smooth but apt to stretch.
I eventually figured out how to combine the two – I bound a curve to the IK spline, then made this curve the Wire Deformer, as its length was limited by the joints, preventing stretching.
Cell Shading 
Unless you particularly need to animate the big long snake thing, you could turn the curve of the IK spline into a hair curve and have it simulate. If you’re in 2013 or above, you’ll have access to nHair which is a delight to work with.