Object Snap or Osnap for short, is an AutoCAD command primarily use to specify precise locations on objects, from your drawing. Therefore this command works to make your drawing more accurate and reliable. For example, you can use an object snap to draw a line to the center of a circle, or to the midpoint or endpoint of any polyline segment.

I think it is safe to say that, most of the advance AutoCAD users, knows how to use AutoLisp, they might even know how to do a routine by themselves as well.  Just like some of my colleagues, back in the previous company that I’ve been work with. Some of my colleagues there are AutoLisp fanatics, they even develop an AutoLisp routine of their own. And I can even say that I know how to do a AutoLisp routine, albeit not that complex as some of my colleagues does.