They apparently actually do have some completely hand-drawn sequences, but I expect the bulk of the animation will be 3D, with appropriate 2 - 2.5D surface shaders. For 3D, they'll probably go pose to pose, with the computer interpolating some things (like physics for floppy ears, say) and the animator manually tuning the intermediate poses for walks and interactions.
Most major 2D animation packages (ToonBoom, Moho, etc.) also have robust integrations now for mixing with real sets ( _everybody_ liked Who Framed Roger Rabbit...), but it doesn't seem that they used them too much.
They apparently actually do have some completely hand-drawn sequences, but I expect the bulk of the animation will be 3D, with appropriate 2 - 2.5D surface shaders. For 3D, they'll probably go pose to pose, with the computer interpolating some things (like physics for floppy ears, say) and the animator manually tuning the intermediate poses for walks and interactions.
Most major 2D animation packages (ToonBoom, Moho, etc.) also have robust integrations now for mixing with real sets ( _everybody_ liked Who Framed Roger Rabbit...), but it doesn't seem that they used them too much.