If History Depth is set to 1, only the current state is stored, i.e., the current state is simply passed through. If History Depth is set to 2, the current state (position 1) and the previous state (position 2) are stored.
History Level defines which one of the stored states the node outputs. To set the History Level, either pass the value to the node’s History Level port or, if the port is unconnected, enter the value directly into the Attribute Manager. If you set History Level to a higher value than History Depth, the node outputs the oldest stored state.
Different rules apply when using nodes such as the Object node, since these nodes are themselves able to output a previous state. In such cases, a History Level of 0 retrieves the previous state instead of the current state.
Use this setting to change the output node’s data type.