Fusion provides general design rules based on common industry standards. You can change each rule's Minimum Value directly in the Design Rules dialog and adjust the preferred value in the right-side details view panel.
Fusion uses the design rule's Preferred Value in the following interactive workflows that support user-specific copper clearances, trace widths, and VIA drill sizes :
The Preferred Value cannot be smaller than the Minimum Value.
General Rules have the lowest priority and Fusion evaluates them last. They should have the smallest Preferred Value in their category. For copper clearance, trace width, or VIA drill size, Fusion uses the larger value between the best applicable rule's Preferred Value and the General Rule's Value.