On 2012 and have run into a problem with curved lines...all curved lines circles etc. The intial draw properly but later when I go back to that portion of the drawing they are converted to rough lines...not a curve anymore segments of straight lines...cant seem to prevent if from happening. Any help would be appreciated.
And you won't prevent it from happening either. That's how AutoCAD and the graphics work together. There's nothing wrong with your circle or arc when you see it this way, however, and you can regenerate the display (REGEN) and it will display accurately again. If you want to select or join something to the nearest point on a curve that is displaying with chords AutoCAD will select the curved object even if it doesn't appear that way.
Check VIEWRES setting, I keep mine at 500, others like to bump it all the way to 20000. Either way at some point you may have to hit REGENALL.
Also check to make sure SHADEMODE is set to 2D.
These settings can be found under Options (op on command line) > Display tab > Display Resolution. You can customize arc and circle smoothness, etc. on a per drawing basis. You should incorporate the changes you make into your drawing template so all new drawings are set the way you want them by default.