Get Key Indices (start/end with alpha from start) with input parameter Time, NumKeys from % from StartKeyIndex, meaning (CurrentKeyIndex(float)-StartKeyIndex)/(EndKeyIndex-StartKeyIndex) by this Start-End, it will be between 0-(NumKeys-1), not number of Pos/Rot key tracks The FramesPerSecond parameter must be the sample rate of the animation data, for example 30.