after i creat some viewports from 3d saved view to generate some for my presentation sheet, the viewports keep disappeared after i changed to other saved view or other sheets. what i can do is go to the original 3d saved view firstly(only need to open), and then shift back to the presentation sheet, all viewports will come back again. anyone knows why?
and sometimes the viewports do not automatic updated, which means something missed. so, i have to re-creat the viewport again from the same saved view scene. why? thanks