I've been using class-to-class spacing and templates. The copper pour usually fills perfectly according to the defined rules. In certain areas, I would like to override the class-to-class rules and have smaller spacings. So I define an area with "override within area / Track and Via styles..." set and another class-to-class rule for this area. A simple example is shown in the screenshot (design file is attached):
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The upper net (Net1) is member of Class1, the lower net (Net2) and the template are member of Class2. The regular spacing between Class1 and Class2 is 4mm. Within "3mm_area" it's 3mm.
I can't quite figure out the result. For some objects the new rules are applied, others keep the old spacings. For example: Why has Pad 2 of C2 4mm spacing and Pad 1 has 3mm spacing? And why is the spacing increasing back to 4mm at the right end of the track.
Does anyone have an explanation for this behaviour?
At the junction of a point where the spacing rules applied could be different such as an Area border, as in this example 3 mm or 4 mm spacings, then the larger will prevail. So for the right-hand track segment end, its Net Class dictates 3 mm spacing inside the area and 4 mm outside. However a short section of the track end is within 4 mm of the Area border and so under the influence of the external rules, so they apply. On the left-hand side the track segment traversing the Area boundary and the component pad 2 are within 4 mm, so they also receive the external rules.
This approach ensures the larger spacings apply in such cases and DRC will also be happy.
Posted - 03 Aug 2015 : 16:41:18
Template_and_Design_Rule_Override_Area.pcb