Outputs the number of elements in the set. For example, if your data set contains the positions of the points on a mesh, the value returned will be the number of points on the mesh. The filter set size corresponds to the size of the set when filtered.
A data set can be filtered with some nodes such as Filter, If, Select, or Raycast. For example, if you insert the Get Set Size to the "If True" branch of an If node, it will return the number of elements that have succeeded the If node condition.
