Polygon tool to define scatter areas inside Vantage

When you decide to go full vantage for end result it is very time consuming to go back to max, vray, sketchup to make easy objects for defining the scatter areas. This would be especially helpful when scattering forest areas in large area projects or at least thats the "problem" I ran into. Making simple polygons or surface objects in Vantage would be a great help. Or even an vertex editable polygon object loaded from cosmos would do if you can add/delete vertexes.