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I don't think there is a built in way to do this, but is there a workaround?

If I just auto route, the ground connections are routes as well, but I want to use a ground plane primarily for the ground connections.

If I draw the ground polygon first, and then auto route, none of the signal air wires get routed (is there a say to allow the 'carving up' or the ground plane like this)?

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  • \$\begingroup\$ I'm not too familiar with EAGLE specifically, but can you manually route the GND traces first, then run auto-route? Or will that override your manual traces? \$\endgroup\$ – Jim Apr 18 '18 at 17:23
  • \$\begingroup\$ If I understand correctly, you don't want a ground plane. If you had a ground plane, there wouldn't be a problem, but it sounds like you want every other signal on there as well? \$\endgroup\$ – pipe Apr 18 '18 at 17:26
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    \$\begingroup\$ What exactly are you trying to achieve? Are you after a board where one layer is a GND plane with as little incursions from other tracks as possible and as far as possible all other tracks on a different layer. If yes then the approach I take is to leave GND till last route everything else with short stubs from SMT pins to vias into the GND plane layer. I finally draw and pour the polygon once all other tracks are routed. I'm not familiar with Eagle but that's my general approach. Some packages let you colour the 'air wires' by net so it is easy to see which routes to initially ignore. \$\endgroup\$ – Warren Hill Apr 18 '18 at 18:43
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    \$\begingroup\$ Also you will get a better PCB if you route manually. \$\endgroup\$ – Warren Hill Apr 18 '18 at 18:44
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    \$\begingroup\$ Can someone please make a wiki article on WHY NOT TO USE THE AUTOROUTER? \$\endgroup\$ – DerStrom8 Apr 18 '18 at 20:03
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If I draw the ground polygon first, and then auto route, none of the signal air wires get routed

That is the problem you should be solving (and/or asking about). If you draw a ground plane your ground wires should get routed. This suggest there is something wrong with your ground plane.

Also routing the ground wires as last is a bad routing strategy. You want to have excellent ground. I would prefer to route my ground first!

(By the way great example of an xy-problem.)

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Last time i used eagle is 2009. If i remember correctly, this is how to do that.

Autoroute everything. Then, run. "rip gnd". It should then remove all your gnd connections. (Assuming you used GND as your ground)

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