[Archive] What about this error

Message by Alexandru Cornogolub:
Hi,
what about this error:
Stacktrace:
java.lang.NullPointerException
at spis.Vol.VolMesh.ThreeDUnstructVolMesh.mapToInternalNodeIndexing(ThreeDUnstructVolMesh.java:2293)
at spis.Vol.VolMesh.ThreeDUnstructVolMesh.mapToInternalNodeIndexing(ThreeDUnstructVolMesh.java:2380)
at spis.Vol.VolMesh.ThreeDUnstructVolMesh.setInternNodeNumbering(ThreeDUnstructVolMesh.java:2465)
at spis.Solver.Poisson.ConjGrad3DUnstructPoissonSolver.init(ConjGrad3DUnstructPoissonSolver.java:341)
at spis.Solver.Poisson.ConjGrad3DUnstructPoissonSolver.(ConjGrad3DUnstructPoissonSolver.java:185)
at spis.Top.Simulation.SimulationFromUIParams.init(SimulationFromUIParams.java:933)
at spis.Top.Simulation.SimulationFromUIParams.(SimulationFromUIParams.java:438)
at spis.Top.Top.NumTopFromUI.(NumTopFromUI.java:157)
at org.spis.ui.ui2num.util.Ui2Num.buildNumTopFromUI(Ui2Num.java:355)
at org.spis.ui.ui2num.command.NumTopFromUICommand.run(NumTopFromUICommand.java:162)
at org.spis.ui.ui2num.command.NumTopFromUICommand.run(NumTopFromUICommand.java:52)
at org.keridwen.core.messaging.AbstractCommand.execute(AbstractCommand.java:200)
at org.keridwen.core.messaging.DefaultBundleController$CallableCommand.call(DefaultBundleController.java:260)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Does someone know what it means?
Thank you,
Alex

Message by Christian Imhof:
Hi Alex,
when does this error message occur? If it is occurring in the simulation initialization I think it is most probably connected with your CAD model. It is important in the modeling process that you exclude your satellite geometry from the volume. This can be done in GMSH when you are defining the volume you are asked to define holes in the volume. In this process step you have to define your satellite model as a hole in the volume. If you do not define your geometry in this way the numeric gets confused since there are “boundaries” in your volume where none should be. You are defining your satellite surfaces which are a boundary for the numerical kernel but these boundaries then do not coincide with the boundaries defined in your simulation volume.
I hope this helps.
Greetings
Christian

Message by Alexandru Cornogolub:
Yes I had a problem in the geo file.I had another problem. In order to get a more slowly varying mesh I defined an intermediate physical surface but it seems that this doesn’t work…
Alex

Message by Christian Imhof:
Hi Alex,
I understand what you are trying to do and I think this should be possible in SPIS. If you want to refine your volume mesh you can define more than one volume in GMSH. So define an inner volume with an intermediate to dense mesh on the external boundary and then another larger one where the mesh gets coarser. The boundary surface between these two volumes has not to be defined as a physical surface. Just then mark both volumes in the physicals definition to belong to the same physical volume group. In a simulation where I have modeled in such a way the tool worked well. I think it is the additional physical element which has in principle no meaning to the numeric kernel which is causing the trouble.
Greetings
Christian

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