This node lets you blend multiple nCaches of the same type. For example you can use the cacheBlend node to blend two fluidShapeCache nodes. An cacheBlend is automatically created and added to your scene when a fluid effect has more than one enabled nCache. See cacheBlend.
Input Weight values let you increase or decrease the amount of influence nCache nodes have on their simulation and they also let you specify how those simulations are blended.
If your nCaches overlap in time, then their Input Weight values determine what percentage of each nCache’s simulations are used by the fluid object during playback. When an nCache node’s weight is 1.0, it is blended with the current nCache and other caches and it fully contributes to the simulation during playback. When an nCache node’s weight is 0.0, it is not blended with the current object’s other caches and it does not contribute to the simulation during playback. You can animate your nCache node’s weights to help smooth the transitions between blended simulations.
Also, nCache weights are normalized such that when overlapping caches have the same weight, then the caches equally contribute to their simulations in their blend regions on playback.
For more information on nCache blending, see Blend and set the weighting of nCaches from the Attribute Editor and Blend nCache clips.