I'm running a dual monitor system with an Nvidia card. The code will stop refreshing the screen when I do mouse moves after a few visits to any other rooms (switching to shader vs model vs render room etc.). I too have problems when working with models (especially with complex spline models). I was working on a chain the other day using a link I built in C3 as the starting point. The whole project turned goofy after that. Weird results when duplicating objects and all sorts of CRAZY behavior. You can also get the code to do all sorts of super weird stuff if you have to create gazillions of objects. I built a scaffolding once which had thousands of individual spars in it. After duplicating and moving bigger and bigger blocks of spars, it started forgetting where I had moved things and where stuff was. Restarting has almost always worked for me. I've ended up with corrupted files on rare occasion. To come full circle, the screen refresh thing is VERY tenacious (happens EVERY time I use the code but the moment it decides to kick in and the way it behaves is always somehow random). The worst part about it is that I can't reproduce it on command. If I could flawlessly reproduce the bug, I'd report it. -Kix

-Kix