Hi All,
I’m new to all this, and spent quite a while trying to figure out the polygon function in Eagle to create a ground plane on my PCB. It was frustrating and I got nowhere… all I got were boxes, nothing would fill!!!
I located a quick tutorial that shows how easy it is… once you know how!
http://www.muzique.com/schem/eagle.htm
Hope it helps you fellow beginners!
Mart.
awesome - thanks for sharing that site
Just in case that link goes cold I’ll repeat it here…
This is done by using the Polygon tool in Eagle. Click on the Polygon button and a new menu will popup directly above the pc board layout. This is the parameters that will be used for the polygon that will be drawn on the board. Make sure that the bottom layer is selected, which will be the far left item of the new menu.
Before we draw the polygon, a couple of the default values need to be changed. The width of the line should be changed to 0.008 The Isolate value, which is how much space will be between the groundplace polygon and the other non-grounded elements needs to be selected. On the current version of Eagle it defaults to 0 which is not useful. I select 0.016 or sometimes 0.024 for the Isolate value.
To make the groundplane, we rename the polygon to the same name that is used for the traces connected to the ground pad. If you have changed the name as taught earlier in this article, it will be called GND. To rename the polygon, we go to “Edit” on the top menu, then “Name” from the dropdown list. Now click on the blue polygon line and the box will popup that allows you to enter a new name for the polygon, which we will enter as GND.
There will be another popup box to confirm that you want to connect the polygon to GND, so select it from the choices and hit the OKAY button. The groundplane should automatically fill the bottom layer of the pcb as shown here. You can hit the F2 key to refresh the view and cleanup any stray bits.
If the groundplane does not appear, click the Ratsnest button on the sidebar. Should it still not appear, you likely do not have the polygon and the ground traces using the same name. Did you rename “S1” as instructed in an earlier paragraph?
Note that the pads for all of the components that were connected to ground are now isolated but tied to the groundplane with short copper traces. The components that are not grounded are isolated electrically from the groundplane by a clear space around each pad and trace, which will be the width that was selected in the “Isolate” menu item.
I know this topic is old and has been covered a number of times more recently in other threads on this Forum,
but i think it has always been in the EAGLE manual… 
You can download a pdf of the tutorial also:http://www.muzique.com/schem/groundplane.pdf
Here are some really good Eagle cad video tutorials. Download them for the best quality. http://tangentsoft.net/elec/movies/
I didn’t want to create a new thread for what is probably a pretty easy question.
I created my own capacitor device and stuck it in my own library. I gave it >NAME and >VALUE text on the symbol.
When I place an already created capacitor from the rcl library, the name comes up as C1, C2, C3, etc for each new capacitor I place. When I place the capacitor that I created with a device name of “C” the C shows up in the Value spot and U$1 is showing up for the name spot. I know this is pretty simple but it is hard to figure a good search term that will reveal this. Maybe I should just dig into some more manuals?
Crap, I was looking at 2 threads and meant to put this post in this
viewtopic.php?t=13912&highlight=name+value+eagle
thread, sorry guys.
Yes, you should read up.
However, it’s very easy and hard to miss. Go into the lib editor, open up the package. Notice the button labeled “prefix” and take it from there.
Ah yes, thank you very much.