The node outputs the index of the closest element to itself. See #102387 for the original design. This is different from the Sample Nearest node in two important ways: * It does not have a geometry input, instead the geometry is taken from the field evaluation context. * The node can exclude the "current" element from the search. * The group id input can be used to build subsets of elements that only consider each other as neighbors and ignore elements with other ids. Pull Request: blender/blender#104619