I have a question: does roblox use interpolation buffer for all base parts or it’s being used only for parts that are descendants of character models?
To answer your question, yes.
Roblox interpolates all replicated parts, not just character parts. Any moving BasePart the server controls gets smoothed on the client. The difference is that characters get extra stuff on top of that, like prediction and humanoid smoothing, which makes them feel responsive but also means parts like the HumanoidRootPart can subtly rotate or shift while moving. Normal parts don’t do that, they’re just interpolated!
I stopped to understand then something. When we play any competitive games which use interpolation buffer for everything what happens they look fine (they feel smooth enough), but when we are doing server tweening (that uses interpolation buffer) it doesnt look good, why?
And what kind of smoothing is applied additionally? Where to read about it? I have never heard about it.