At Toonfic, we have always been captivated by a singular creative challenge: how do you take rigid, mathematical 3D structures and make them feel as warm, organic, and spontaneous as classic hand-drawn cell animation? The answer lies not just in the rendering engine, but deep inside the skeletal rigs. Typically, 3D mechanical models are locked to strict joints. But to make characters like our beloved robot series smile, run, and interact with believable emotion, we developed a proprietary squash-and-stretch rig model.
THE SCIENCE OF SQUASH & STRETCH IN 3D
Squash and stretch is the most critical of the 12 basic principles of animation. It gives the illusion of weight and volume to a character. While easy to draw on paper, translating this to 3D rigging requires calculating complex volume conservation formulas in real time. If a character squashes flat, its sides must dynamically expand outwards to maintain the exact same mathematical volume.
We aren’t just animating metal blocks. We are animating hearts wrapped in custom shaders. The rigidity must completely vanish the second a character experiences joy.
— SORA KIM, LEAD RIGGER & CREATIVE DIRECTOR
BRIDGING MODERN PHYSICS WITH CLASSIC TECHNIQUE
To make characters like the Robo-Chums feel nostalgic yet state-of-the-art, our tech-artists stack custom deformation layers over traditional joint hierarchies. This secondary animation track handles details like cheek-puffs when speaking, soft antenna wiggle, and elastic eye-scaling that matches camera positions. This is how we ensure that no matter the angle, every render makes you smile.
