First off let me say that I'm not sure this is a bug in mason or a problem 

with my implementation.  Basically I have agents that exist in 3d space 

and in a network (visualized by SpatialNetwork3D). Each of these agents 

has the ability to create/destroy links to other agents in the network as 

the simulation progresses.  My problem is two-fold (though I expect they 

are very much related).  



First -

When the simulation is running, the network object is being updated 

correctly however the edges that are being visualized seem to only be 

edges which were present when the simulation began (some type of edge 

portrayal update problem?).



Second - 

After some time running the simulation for a given (not consistent) number 

of generations I recieve this error



Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

 at sim.portrayal3d.network.SimpleEdgePortrayal3D.getModel

(SimpleEdgePortrayal3D.java:129)

 at sim.portrayal3d.network.NetworkPortrayal3D.updateModel

(NetworkPortrayal3D.java:90)

 at sim.portrayal3d.FieldPortrayal3D.getModel

(FieldPortrayal3D.java:182)

 at sim.display3d.Display3D.updateSceneGraph(Display3D.java:1142)

 at sim.display3d.Display3D$16.run(Display3D.java:1085)

 at java.awt.event.InvocationEvent.dispatch(Unknown Source)

 at java.awt.EventQueue.dispatchEvent(Unknown Source)

 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown 

Source)

 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)

 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown 

Source)

 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)

 at java.awt.EventDispatchThread.run(Unknown Source)



I'm not able to attach source code, but I will provide as much requested  

additional information that I can. 



Thanks so much for your help,



Jesse St. Charles

Oak Ridge National Laboratory

Applied Software Engineering Research Group