Hi!
I am a complete and utter n00b when it comes to electronics and PCBs… but I am trying to learn, and I was looking at the sparkfun bi-directional logic shifter (https://www.sparkfun.com/products/12009) Eagle files and no matter how I watched I could not understand how the Ground is connected to the rest of the PCB.
I know I am missing something, but I don’t know what… I would like to learn thought so if anyone out there could enlighten me I would be very happy 
On the schematic, notice that ground is connected to each connector. This is also obvious on the PCB if you click on “X” (ratsnest).
davep238:
On the schematic, notice that ground is connected to each connector. This is also obvious on the PCB if you click on “X” (ratsnest).
Aha, so basically the entire bottom of the PCB is one big ground. I was very much confused by the “X” part at first… but that was easily explained once I found the “Ratsnest” button which looks much more like a molecule than an X.
If I understand this correctly this is a fairly simple board… but DAMN that drawing is complex with all the layers. I am crazy impressed by anyone doing this for a living.
How come that the ground connection was not visible until you chose rats nest? Is it something that is “implied” when you do a PCB?
Lol… also how do I get rid of the rats nest once I have pushed the button?