Keepout and Restrict

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Contents

Overview

Keepout, and restrict polygons are powerful tools at your disposal as a PCB designer. Keepout is used when you don't want components placed within an area, like edges of a board, or where your heatsink will be placed.

Restrict polygons make sure the specific copper layer cant be placed within the polygon. We use them to keep other traces away from noise sensitive traces and parts. Both keepout, and restrict together are used to keep part, and copper away from metal standoffs on our Sick of Beige cases.

How to use

Create a polygon with one of the layers described below, covering an area for which you need keepout, or restrict.

Creating Eagle Polygons

Special Layers you could use

tKeepout / bKeepout

When a component contains a keepout layer on its perimeter, the DRC checks if there are overlaps with your keepout polygon. If there are overlaps, you will be informed about it through the error report.


Eagle-wiki-keepout restrict-ovelapping-keepout.png

Keepout errors

Eagle-wiki-keepout restrict-standard-board.png

Keepout clearance for components overlaps

tRestrict/bRestrict/vRestrict

These layers check for overlap of top copper, bottom copper, and vias when running a DRC with “Check Restrict” toggled under Misc. Tab in DRC. Also informing you about overlaps in the DRC error report.

Eagle-wiki-keepout restrict-part-with-overlapping-restrict.png

Restrict errors

Eagle-wiki-keepout restrict-DRC window.png

DRC window, Miscellaneous Tab

Eagle-wiki-keepout restrict-cleared-out-plane.png

This will also cut through, or prevent power planes. Great for protecting noise prone areas.

Conclusion

You can turn-off tKeepout/bKeepout layers under View>Display/Hide Layers to bypass the check.

Restrict will still be checked even it's layer is off, you should un-check it in the DRC menu if bypassing is required.

Eagle-wiki-keepout restrict-DP-logo.png

Here’s an interesting use of Restrict layer. You could etch away your logo or text using restrict..