Interpolation calculates values between known samples, such as the positions or rotations stored in animation keyframes.
What happens between two poses
If an object is at one end of a shelf at the start and the other end later, the keyframes alone do not describe every intermediate moment. Interpolation fills that gap. Linear interpolation of a position gives evenly changing values between two keys. A step or hold mode keeps the previous value until the next key, creating a deliberate jump.
The method affects the result
Curved interpolation can control how the value approaches and leaves a key. Different data types also need different handling: rotations are not always best treated like ordinary three-number positions. Core glTF animation supports STEP, LINEAR and CUBICSPLINE modes. Authoring curves may need conversion or sampling during export, so the exported movement deserves its own review.
Choosing an expressive transition
A museum reconstruction might need a precise, steady movement, while an animated illustration may benefit from a softer arrival. For a Painta asset, choose the interpolation that serves that intention and inspect the transition between clips or loops. Interpolation cannot invent missing artistic decisions: if an object should pause halfway, that pause needs to be represented in the animation.