They can be referred to by their GUID.
To create a region node, use the Create Menu and Create region.
Region nodes can be clicked and dragged, and the shape can be changed by dragging any corner.
New vertexes can be created by using the Select and Translate Tool. Click and drag one of the small circles along the edge of the Region Node, to create another vertex.
Each region node can be color-coded by modifying the COLOR property in the Region Node's properties panel.
To delete a point, highlight it and click delete.
HSL functions on the client and server can return a random point inside the shape, or determine if a random point is or is not inside the node's space. Functions exist on both the server and client:
IsPointInRegion(regionNode as noderef, point as vector3) as boolean RandomPointInInRegion(regionNode as noderef) as vector3