the weight of animation
this calculates the blend weights for one curve.
weights are distributed so that the top layer gets everything. if it doesn't use the full weight then the next layer gets to distribute the remaining weights and so on. once all weights are used by the top layers, no weights will be available for lower layers anymore unity uses fair weighting, which means if a lower layer wants 80% and 50% have already been used up, the layer will not use up all weights. instead it will take up 80% of the 50%.