Extra routing room by suppressing pads

[brian]

I'm laying out a 16-layer board that calls for unused pads to be
suppressed on layers 3-14. I'm accomplishing this by using the
"Internal Layer - optional" checkbox in Padstack Editor and the
"suppress unconnected pads" checkbox in the Manufacture-Artwork dialog
in Allegro. What I would like to do is use the extra room given by
suppressing the unused pads for routing. Is there a way to only show
the used pads during routing? Ideas of how this could be done (but I
don't know how to implement any of them) include turning each pad on or
off by layer (labor intensive), setting all pads "off" until connected
on a particular layer (or starting with a small pad and then oversize
the pad if a connection is made) or somehow backannotating from the
gerber files.

It seems a big waste to have all that extra room to go unused. Thanks
in advance for your help. I'm using Allegro version 15.2.

brian

 

[daytripper]

On 8 Mar 2006 09:43:57 -0800, "brian" <brian.heeter@navy.mil> wrote:

I'm laying out a 16-layer board that calls for unused pads to be
suppressed on layers 3-14. I'm accomplishing this by using the
"Internal Layer - optional" checkbox in Padstack Editor and the
"suppress unconnected pads" checkbox in the Manufacture-Artwork dialog
in Allegro. What I would like to do is use the extra room given by
suppressing the unused pads for routing. Is there a way to only show
the used pads during routing? Ideas of how this could be done (but I
don't know how to implement any of them) include turning each pad on or
off by layer (labor intensive), setting all pads "off" until connected
on a particular layer (or starting with a small pad and then oversize
the pad if a connection is made) or somehow backannotating from the
gerber files.

It seems a big waste to have all that extra room to go unused. Thanks
in advance for your help. I'm using Allegro version 15.2.

brian

Unless these are associated with blind or buried vias, you still have to avoid
the *drill diameter*, plus tolerance (positional plus deflection) anyway.

And depending on your reference layer clearances/antipad diameter, you'd at
best be routing lines over voids on the reference planes.

Hell, son, I *shoot* designers for that! ;-)

I may be missing something (it's a bit late here, I just flew back from 10
days in Exuma and I'm still wound up like a top but this sounds like a
low-payback/high-DRC headache looking for a place to happen...

Cheers