Maybe it's just me, but after updating my assembly the updates don't seem to happen in the motion study that I have created previously. I can see the nuts and bolts there but when I save as an AVI i cant see the new hardware that I've just added in the video. This happens for both exploded animations and moving linear animations. Some of the animations are complex and a pain to setup again to see these updates. Is this a bug with SolidWorks or is there a way around this?