The Fixed Point Error in 2D Animation and How to Fix It
In 2D animation, a frequent and harmful flaw is the fixed point or pinning. This occurs when an animator unintentionally anchors a limb or part of a character to a specific coordinate on the plane. The consequence is that that part stops moving naturally, destroying the physics and weight of the character. 🎬
What Causes the Fixed Point in a Character?
When a foot or hand gets stuck in the air, the rest of the body moves around that point. The result is that the character appears to slide or float, as it loses all visual connection with the ground. The posture becomes unnatural and the illusion of believable physical movement is completely broken.
Direct Consequences of Pinning:- The character loses its weight and seems weightless.
- The action of walking or running lacks force and realism.
- An evident disconnection is generated between the character and its environment.
A character with its feet literally nailed to the ground would have a very different problem and would probably need a carpenter, not an animator.
Techniques to Prevent the Fixed Point from Appearing
The key to preventing this error is to conceive the character's body as a connected system. No part moves in isolation. When animating a step, the leg, hip, torso, and even the arms must adjust their position to maintain balance. 🦵➡️🦾
Essential Tools and Methods:- Use clear and defined motion arcs for each joint.
- Constantly verify the character's spatial relationship with the scene elements.
- Take advantage of the onion skin tool to supervise consistency throughout the sequence.
- Draw reference keyframes that define the starting and ending poses of the movement.
Steps to Correct an Animation with Pinning
If the fixed point error is already present in the scene, it is necessary to readjust the entire trajectory. It is not enough to move the affected limb; all parts of the body linked to it must be reviewed to restore fluidity. ✏️
Normally, correcting involves redrawing several intermediate frames. For example, for a step, the foot must lift, advance in an arc, and land credibly. Reviewing the animation frame by frame, paying special attention to how the body's weight is transferred, is essential to reestablish the connection with the ground and give solidity to the movement.