This node sets an attribute on each point or primitive in the selected
Group sequentially (for example, it would set the attribute on the first
point in the group to
0, the second point in the group to
1, and so on).
This differs from the built-in point/primitive number because this node only
sets the attribute for points/primitives in the selected group.
The group to set the attribute on.
Whether the group contains primitives or points.
The name of the attribute in which to store the index.