[JAVA3D]

[Liu Samuel]

hi all,
There is a NullPointerException occured when I attempted to detach a BranchGroup from 
the locale, there is a collision detection behavior serves as a child of the 
BranchGroup. The call trace is:

java.lang.NullPointerException
        at 
javax.media.j3d.TransformGroupRetained.getCurrentChildLocalToVworld(TransformGroupRetained.java:1029)
        at 
javax.media.j3d.TransformGroupRetained.getCurrentChildLocalToVworld(TransformGroupRetained.java:1025)
        at 
javax.media.j3d.TransformGroupRetained.transformBounds(TransformGroupRetained.java:1000)
        at 
javax.media.j3d.WakeupOnCollisionEntry.updateCollisionBounds(WakeupOnCollisionEntry.java:410)
        at 
javax.media.j3d.GeometryStructure.processCollisionDetection(GeometryStructure.java:866)
        at 
javax.media.j3d.GeometryStructure.processMessages(GeometryStructure.java:214)
        at javax.media.j3d.StructureUpdateThread.doWork(StructureUpdateThread.java:83)
        at javax.media.j3d.J3dThread.run(J3dThread.java:250)

Seems to be an internel exception. Why? Bug of j3d collision detection? Any 
walkarounds?

Many many many thanks for your help:-)

Liu