The value depends on the movement of the object into Y direction. Every pixel the object moves into Y direction increases the value a little bit. Once end is reached the value is reset to begin. In contrast to
Anim_Y the value always moves towards end, not depending on whether the object moves upwards or downwards.
See the
animation documentation for further explanations of the animation system.
PlayAnimation("Lift", 5, Anim_AbsY(0, 0, GetAnimationLength("Lift"), 25), Anim_Const(1000));
Plays the animation "Lift" in slot 5 and superimposes any other potential animations played in slot 5. The animation is playdethe faster the faster the object moves into Y direction. After it moved 25 pixels the animation has been played from its beginning to its end and will be restarted.