This film was pretty fun. There was lots of cartoony expressive animation to work with, which sometimes caused some headaches, but every shot was full of life.
I created scripts for the characters to set up parameters for their fur to get rid of the areas where the fur would pass through their various clothing styles by default. This helped me get to the shot-specific problems more quickly.
I also developed and animated a "hood up" to "hood down" approach for Alvin that let his hood transition smoothly from pose to pose.
There was a lot of classic Technical Animation challenges on this film. Simon's glasses usually had to be re-animated to sit better on his face fur. And as each character was animated into extreme poses their fur had to react accordingly; folding down as cloth moved over it and puffing back out when the cloth moves off.
On Theodore especially I troubleshot rig deformation issues and fixed some muscle popping that happened frequently.