At 03:42 PM 9/10/2010, you wrote:
On Sep 10, 2010, at 1:01 PM, DJ Delorie wrote:
> I figure we need each layer to specify:
>
> * type (copper, silk, mask, anti-copper, keepout, etc)
There are no types, there are only properties.
The conductors may not be copper. I've even worked with a board that
had two different conductive materials on the same physical layer.
Wouldn't that by definition then be two different physical layers,
just like the solder mask and silk screen are two physical
layers. The fact that they connect without vias doesn't mean to me
they are the same physical layer. I've worked with boards that had
buried resistors. The resistors were a layer of conductive material
that had a controlled resistivity in contact with a copper
layer. The resistors were considered a separate layer.
The support layers are also not always FR4. The board I noted above
had different numbers of layers in different places, and the support
layers weren't all the same material and thickness.
Sounds suspicious. Are you sure you aren't talking about an assembly
with boards and a case? Bolts aren't normally considered vias. ;^)
Rick
_______________________________________________
geda-user mailing list
geda-user@moria.seul.org
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user