Why don't you use a layer specific keep-out track? Place a skinny track 1
mil or so between the pads and when you pour the polygon, it will avoid the
area between the two SMD pads.

Tony



> -----Original Message-----
> From: Jenkins, Charlie [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, November 21, 2001 10:35 AM
> To: 'Protel Users Mailing List'
> Subject: [PEDA] How to use objects as keepouts?
>
>
> I noticed at some point that a keepout check box was added to the fill
> properties.  I have long wanted to place a top or bottom only keepout in
> between certain surface mount pads such that copper pours were prevented
> from filling in between pads that had a layer specific keepout.
>
> Unfortunately to make the keepout layer-specific the fill that will be
> turned into a keepout must be on a single side layer, like Toplayer or
> Topoverlay.  Unfortunately the fill must be associated with a conductive
> layer to prevent polygons on that layer from over-running the
> fill-made-keepout.  This now leaves a chunk of copper in between
> the pads in
> place of the pour.  Better but not what is needed.
>
> I thought of using very thin traces in the form of a rectangle with no net
> to block the migration of the pour. Of course there would have to be a set
> of rules written to keep the DRC happy.
>
> Ideally we could make an all-sides keepout fill be layer specific by
> selecting the desired layer in a "Constrain Keepout to a Specific Layer"
> pull down but that does not exist yet.
>
> Does anyone have any better ideas how to keep pours on a given layer from
> passing through certain pads.  The solution should be able to be
> saved with
> the footprint and should not involve using larger clearance rules.
>
> The reason for this requirement is to keep the copper from between surface
> mount pads when using circuit board routers to prototype SMT boards. Since
> solder masking is typically not used with this type of prototype, copper
> under components like caps and resistors can lead to shorts from paste
> reflow.  The selective keepout would prevent the polygon from
> getting under
> some of these small components.
>
> Charlie Jenkins, Pioneer

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