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Changing the Default Via? Add more via choices to the design?

split63

 I'm using Allegro PCB editor 16.01.

I would like to change the current board via to another via.   By selecting a via on the board and then right clicking, I'm given the choice to "Modify design Padstack" by entering in new parameters.  However, I would prefer to globally change the current via to another existing via padstack, currently in the padstack library.  How is this done?  

How do you set the default via?

Also, in the fanout creation/option screen, you can select the via you want to use when creating fan-outs.  However, only the current via shows up and there is no option to add/use other vias.  How do I add more existing vias to the design so that they will appear on the list of choices?

 

Thanks

  • redwire

    Be sure to get to know the Constraint Manager (CM) before getting too deep into Allegro.  Vias are setup via the CM.  You can select vias by net class, default, board region, etc.. Very powerful.

    You can globally or individually replace the via in use by Tools->Padstack->Replace

     

  • Ejlersen

    Hi, 

    Inside Constraint Manager select Physical, Physical Constraint Setup and click the via cell for the Default PCS. All nets pointing to this constraint set will then inherit the new via settings.

    In the Nets, All Layers you'll be able to change what constraint set is being used.

    Notice that the constraint manager is a very strong tool and it just takes a little time to learn the concept of using it.

    In the Physical Constraint Set section you setup constraints sets.

    • A Constraint set is a placeholder for a specific set of constraints (widths, via types etc.).
    • You can create as many constraints sets as you want.

    I often prefer to compare constraint sets to types inside Office. Selecting a specific type gives you the font, text size etc.

    In the Nets section you specify what nets should refer to what constraint sets

    • All constraints from the constraint set will be inherited by the nets refering this constraint set
    • Changing a constraint value in the constraint set will change it for the nets refering to the constraint set 
    • Exceptions are overrides which are marked in blue, they will never inherit anything from constraint sets. You can restore the inheritance behaviour by (clear) or deleting the value of the particular field

    I hope this helps

  • split63

     Thanks,  Constraint Manager was the answer

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