Hi, > I think your next step in your plan of attack should be to test the > model without visualization, but in your loop main loop, before you > call schedule.step(), experiment with (1) a call to > Thread.sleep(MILLISECONDS_PER_TICK), and (2) a bogus call to > Thread.currentThread().isInterrupted() to see if either may be causing > the problem. (Sorry for the long delay in replying) In the end, I didn't take this any further - I just dropped the target frame rate and this worked better (at 15fps target I got about 12.9 actual). For my next project, I'll be writing my own Controller, but if I run into the same problem I'll posts details here. yours, rob -- Rob Alexander (E-mail: [log in to unmask]) Research Associate, Dept of Computer Science, The University of York, York, YO10 5DD, UK Tel: 01904 432792 Fax: 01904 432708