Polygons inside cutouts inside polygons

Reece R. Pollack wrote:

I'm laying out a board with a ground pour over layer 1. To do this

I've created a polygon that follows the board contour, named it GND,

and set the rank to 6. That works as expected: pins and pads

connected to GND on the schematic automatically connect to the pour

with thermals.

 

In a couple of small areas I want to exclude the ground pour. If I

create a polygon on layer 1 as a cutout I can route nets within it,

but signal polygons placed inside the cutout don't get processed

regardless of rank....................

 

That's correct as described in HELP/POLYGON/Polygon Cutout

 

...............How can I exclude the ground pour while still being able to

create

polygons in the area?

You can make the GND pour have a clear area in the centre by not creating a

simple square polygon around your board but by defining the outer  and inner

edges of the polygon connected by a thin canal. All defined as one polygon.

Think of it as a land locked lake with a small canal to the sea.

When you ratsnest you will see the canal. This you get rid of by moving one

side of it towards the other but if you place the centre of the polygon wire

on top of the other you will get illegal polygon warnings so you have to

stop just short of it.. It is best to make the alternate grid 'finest. so

you can get really close. Your polygon will have wire widths, say 10mil , so

overlap by half this and you will be safe.

HTH

Warren

--

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Reece R. Pollack wrote:

I'm laying out a board with a ground pour over layer 1. To do this

I've created a polygon that follows the board contour, named it GND,

and set the rank to 6. That works as expected: pins and pads

connected to GND on the schematic automatically connect to the pour

with thermals.

 

In a couple of small areas I want to exclude the ground pour. If I

create a polygon on layer 1 as a cutout I can route nets within it,

but signal polygons placed inside the cutout don't get processed

regardless of rank....................

 

That's correct as described in HELP/POLYGON/Polygon Cutout

 

...............How can I exclude the ground pour while still being able to

create

polygons in the area?

You can make the GND pour have a clear area in the centre by not creating a

simple square polygon around your board but by defining the outer  and inner

edges of the polygon connected by a thin canal. All defined as one polygon.

Think of it as a land locked lake with a small canal to the sea.

When you ratsnest you will see the canal. This you get rid of by moving one

side of it towards the other but if you place the centre of the polygon wire

on top of the other you will get illegal polygon warnings so you have to

stop just short of it.. It is best to make the alternate grid 'finest. so

you can get really close. Your polygon will have wire widths, say 10mil , so

overlap by half this and you will be safe.

HTH

Warren

--

Viewed / responded via the newsgroup at

news.cadsoft.de

On 06/27/2013 04:14 AM, Warren Brayshaw wrote:

Reece R. Pollack wrote:

I'm laying out a board with a ground pour over layer 1. To do this

I've created a polygon that follows the board contour, named it GND,

and set the rank to 6. That works as expected: pins and pads

connected to GND on the schematic automatically connect to the pour

with thermals.

 

In a couple of small areas I want to exclude the ground pour. If I

create a polygon on layer 1 as a cutout I can route nets within it,

but signal polygons placed inside the cutout don't get processed

regardless of rank....................

 

 

That's correct as described in HELP/POLYGON/Polygon Cutout

I was just hoping I'd either read it wrong, or there was some trick I

hadn't discovered. sigh

...............How can I exclude the ground pour while still being able to

create

polygons in the area?

 

You can make the GND pour have a clear area in the centre by not creating a

simple square polygon around your board but by defining the outer  and inner

edges of the polygon connected by a thin canal. All defined as one polygon.

Think of it as a land locked lake with a small canal to the sea.

 

When you ratsnest you will see the canal. This you get rid of by moving one

side of it towards the other but if you place the centre of the polygon wire

on top of the other you will get illegal polygon warnings so you have to

stop just short of it.. It is best to make the alternate grid 'finest. so

you can get really close. Your polygon will have wire widths, say 10mil , so

overlap by half this and you will be safe.

Thanks for taking the time to respond. I'd considered something like

this, but it's just too much trouble for what I need.

I think I'll post an idea in the Suggestions group for supporting

subtractive polygons.

-Reece