This is just a player animation engine I made for my future mods; Partially because I couldn't find compatible libs for some odd reason.
At the very moment it, it works in tangent with a blockbench extention, along side a pre-rigged steve model, to create animations for the player(s); The extension handles the parent-child relationship of the body and the arms and head bones (yes, that new blockbench feature). It also supports multiplier along with an API for easier use alongside a full Documentation for using and how it works in general. Only caveat is that it still doesn't support other forms of frame interpolation except linear.
The best use cases for this mod is when you need simple animations and don't want to overcomplicate yourself with configuration since all you need is to simply register (details in the repo)
