Apply teardrops to a 2D PCB

Use Design Rules to add teardrops on a 2D PCB.

1. On the Rules toolbar, click Rules > Design Rules .

2. In the Design Rules dialog, click General Rules.

3. Select a teardrop rule in the list. Select Enabled for each connection type you want:

   • Via Teardrop
   • PTH Pad Teardrop
   • SMD Pad Teardrop
   • Trace-to-Trace Teardrop (Taper)

4. In the parameters panel for the selected rule, set Length and Width:

   • For Via Teardrop, PTH Pad Teardrop, and Trace-to-Trace Teardrop (Taper), both values are percentages of the object size. For vias and PTH pads, the object size is the via or pad diameter. For trace-to-trace connections, it is the width of the wider trace.
   • For SMD Pad Teardrop, Length is a percentage of the trace width at the pad. Width adds the specified percentage to the original trace width. At 0%, the teardrop width equals the trace width. At 100%, it is twice the trace width.

5. Set the remaining options for the rule as needed:

   • Curved Sides: Draw teardrop sides with arcs instead of straight segments. When a curved side cannot be drawn safely, Fusion uses a straight segment instead.

   • Auto-Generate: Add teardrops automatically for every qualifying connection. When Auto-Generate is off, teardrops are added only for wires whose Teardrop property is On.

   • Adjust to available space:

     State	Behavior
     On	Fusion places the largest teardrop that fits and reports adjustments in the Warnings tab of the DRC panel.
     Off	Fusion skips teardrops that do not fit at the requested length and width. Skipped connections can also appear as warnings.

   • Ignore Violators:

     State	Behavior
     On	Fusion places the teardrop and reports a copper clearance error.
     Off	Fusion skips teardrops that would cause a clearance violation.

6. Apply teardrops to connections:

   • Turn on Auto-Generate to add teardrops to all connections that match the rule.

   • Or select a wire. In the Inspector, set Teardrop:

     Value	Behavior
     Auto	Follows the rule Auto-Generate setting.
     On	Adds a teardrop when the connection matches an enabled teardrop rule.
     Off	Does not add a teardrop.

     The Teardrop property appears on all wires, but it affects only wires that connect to a via, PTH pad, SMD pad, or wider trace.

     Note: Teardrops do not appear when they would violate clearance and Ignore Violators is off.

7. Review teardrop results in the DRC panel after you edit the board or run a design rule check.

8. In the Warnings tab, check for adjustments, skipped teardrops, or curved sides that fell back to straight segments. When Ignore Violators is on, clearance problems appear as errors. Select an entry to locate the connection on the board.