Hi, I am trying to reconstruct some Background and Trident MC files with the attached (Holly's) steering file. It worked for me well few months ago, but now I am getting this exception Do you have any clue what is the problem. Rafo java.lang.NullPointerException at org.hps.recon.tracking.MaterialSupervisor$SiStripPlane.setOrigin(MaterialSupervisor.java:274) at org.hps.recon.tracking.MaterialSupervisor$SiStripPlane.<init>(MaterialSupervisor.java:142) at org.hps.recon.tracking.MaterialSupervisor.buildModel(MaterialSupervisor.java:78) at org.lcsim.recon.tracking.seedtracker.SeedTracker.detectorChanged(SeedTracker.java:175) at org.lcsim.util.Driver.detectorChanged(Driver.java:171) at org.hps.recon.tracking.TrackerReconDriver.detectorChanged(TrackerReconDriver.java:129) at org.lcsim.util.Driver.detectorChanged(Driver.java:171) at org.lcsim.util.DriverAdapter.detectorChanged(DriverAdapter.java:86) at org.lcsim.util.DriverAdapter.recordSupplied(DriverAdapter.java:72) at org.freehep.record.loop.DefaultRecordLoop.consumeRecord(DefaultRecordLoop.java:832) at org.freehep.record.loop.DefaultRecordLoop.loop(DefaultRecordLoop.java:668) at org.freehep.record.loop.DefaultRecordLoop.execute(DefaultRecordLoop.java:566) at org.lcsim.util.loop.LCSimLoop.loop(LCSimLoop.java:151) at org.lcsim.job.JobControlManager.run(JobControlManager.java:424) at org.hps.job.JobManager.run(JobManager.java:29) at org.lcsim.job.JobControlManager.run(JobControlManager.java:182) at org.hps.job.JobManager.main(JobManager.java:18) ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the HPS-SOFTWARE list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1