[Archive] How to define the groups when the spacecraft surface is also the external boundary?

Message by Lianghai Xie:
I am new to the SPIS. Now I’m trying to study the charging of lunar surface. It is different from spacecraft, since lunar surface can also be an external boundary in the simulation. I defined a cubic as the computational volume, with one of the face as the lunar surface (spacecraft surface) and the others as the external boundary, but met the following error:
java.lang.ArrayIndexOutOfBoundsException: 15163
at org.spis.ui.ui2num.util.PenelopeIdToSpisId.(PenelopeIdToSpisId.java:90)
at org.spis.ui.ui2num.util.Ui2Num.buildNumTopFromUI(Ui2Num.java:264)
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$CallableCommand.call(DefaultBundleController.java:259)
at java.util.concurrent.FutureTask$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)
Is the external boundary must closed surfaces? However, i tried to define all the faces of the cubic as the external boundary, the error still exist. So, please tell me how to define the groups for such a case!

Message by Jean-Charles Mateo-Velez:
one face for the spacecraft + 5 other for external + volume for plasma is OK normally.