Trace width was used to define the copper, but shapes and keep-outs were used for the actual connections. Of course, it was
static copper that did not yield to outside influence. Satisfying that guy (who left every day at noon!) was a pain but I came
out of it able to control the copper to his liking. He basically wanted proof that it could not be designed any other way than
what was stipulated. I've used those lessons over and over for design verification.
Figure 5. Selecting the appropriate rules for a region happens as you create the shape. Defining what that means in terms of spacing falls on
the selections seen here and made in the Referenced Spacing Cset of the Region tab of the Spacing Constraint Set worksheet.
It's hard to overstate the importance of getting the right amount of space for each situation. Prior to fabrication, the entire
panel is a solid sheet of copper. The process in the factory is to etch away the parts we don't need. What we're creating in the
factory is the air-gaps more than the metal. If we're doing an additive process, well then the air gaps still matter. The numbers
may shrink so we'll be even more vigilant in that case.
6 www.cadence.com
Controlling Air Gaps Using OrCAD X and Allegro X Tools
