Design Rules categories

Fusion organizes design rules into categories. Each category checks a specific aspect of your design, such as copper clearance, trace width, or annular ring width. All categories are enabled by default and run during both checking levels:

Live DRC: Runs automatically at the end of any interactive workflow when the design changes, so violations appear as you work.
Manual DRC: Runs when you start a check, either with the DRC command or by clicking Check Design Rules on the rules toolbar. Manual DRC reviews the entire design at once.

Rule types

Each category is either unary or binary, based on how many objects it evaluates:

Unary: Checks a single object against a parameter, such as the width of one trace or the annular ring of one pad.
Binary: Checks the relationship between two objects, such as the clearance between two copper areas.

Rule categories

Category	Description	Type
Copper Clearance	Minimum spacing between copper objects on different signals.	Binary
Components Exclude Clearance	Minimum spacing around component keep-out areas.	Binary
Solder Mask - Silkscreen Clearance	Minimum spacing between silkscreen and solder mask openings.	Binary
Board Outline Clearance	Minimum spacing between copper and the board outline.	Binary
Drill Clearance	Minimum spacing between drilled holes.	Binary
Copper - Restrict Clearance	Minimum spacing between copper and copper keep-out areas.	Binary
Via Restrict Clearance	Minimum spacing between vias and via keep-out areas.	Binary
Unconnected Lines	Flags connections that are drawn but not routed.	Unary
Drill Size	Minimum drill diameter for holes and vias.	Unary
Copper Width	Minimum width of copper traces.	Unary
Acute Angle	Flags trace angles too sharp to manufacture reliably.	Unary
Air Wire	Flags unrouted connections between pads.	Unary
Wire Stub	Flags short dangling trace segments.	Unary
Matched Signal Lengths	Checks that grouped signals meet length-matching requirements.	Binary
Teardrops	Adds and checks teardrop shapes where traces meet pads, vias, or wider traces. Reports spacing and fit issues as warnings.	Unary
Annular Ring	Minimum copper ring width around drilled holes in pads and vias.	Unary
Solder Mask Opening	Size of the solder mask opening around pads and vias.	Unary
Stencil Opening	Size of the stencil opening for SMD pads.	Unary

Some categories use a Minimum value for manufacturability and a Preferred value for design intent. The Preferred value drives automatic behaviors in interactive workflows, while the Minimum value determines when Fusion flags a DRC error. Categories where only manufacturability matters, such as Annular Ring, Solder Mask Opening, and Stencil Opening, use a Minimum value only.