# What algorithm is mostly used to interpolate animations?

Because DCC tools supports very many options, we resample the animation curve splines, but I think it still need to be interpolated. I think there's some de facto standard for this animation interpolation. Or no interpolation. Can I know what's the mostly used interpolation method?

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The most common form of interpolation is linear interpolation.

However, in the case of animating curve splines, another common one is spline interpolation.

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In general, you should have an interpolation function f of any kind that satisfies: f(0) = 0; f(1) = 1; f(x) is continuous for all 0 < x < 1 (this can obviously be relaxed if you want jumps); 0 <= f(x) <= 1; and f(x) increasing for 0 < x < 1 (unless you want goofy effects).

Ones that are computationally easier to do are preferred. For example, one may use f(x) = 3x^2 - 2x^3 instead of f(x) = sin(pi x). Both of these have roughly the same shape over the unit interval.

Once you decide on your interpolation function, then simply compute A * f(x) + B * (1 - f(x)) to interpolate between the two values.

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