Zones and Copper Planes¶

Copper zones (fills / pours) cover a board area with copper — typically used for ground planes or power planes. This is a standard practice in professional PCB design.

Why Use Zones?¶

Ground plane — reduces EMI noise and improves RF signal integrity
Power plane — reduces voltage drop on power rails
Larger copper area → lower impedance → better heat dissipation

What Is a Zone?¶

Board with GND zone (top view):

┌─────────────────────────────────────────┐
│ ░░░░░░░[R1]░░░░░░░░░░░░░░░░░░░░░░░░░░░ │  ← GND copper fill (░)
│ ░░░░░   ┊  ░░░░░░░   ┊  ░░░░░░░░░░░░░ │
│ ░░░░░  [U1] ░░░░░  [C1] ░░░░░░░░░░░░░ │
│ ░░░░░   ┊  ░░░░░░░   ┊  ░░░░░░░░░░░░░ │
│ ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ │
└─────────────────────────────────────────┘

Legend:
  ░ = GND copper fill
  ┊ = clearance gap around pads on other nets
  [R1] = footprint (GND pads connect directly to the fill)

Each zone has:

Property	Description
Net	The net name (e.g. `GND`, `VCC`)
Layer	Copper layer (e.g. F.Cu, B.Cu)
Priority	Higher-priority zones override lower ones where they overlap
Clearance	Minimum gap from pads and traces on other nets
Outline	The polygon you draw to define the zone boundary

Quick Ground Plane¶

The fastest way — use Fill GND Plane:

Go to Tools → Fill GND Plane
WireFrame automatically:
- Reads the board outline from Edge.Cuts
- Creates a GND zone covering the entire board interior
- Computes clearance gaps around all pads and traces not on GND
- Connects GND pads directly into the fill

Before Fill GND:              After Fill GND:
  ┌────────────┐                ┌──░░░░░░░░░░░┐
  │  [R1] [C1] │                │░░[R1]░[C1]░░│
  │            │                │░░░░░░░░░░░░░│
  └────────────┘                └──░░░░░░░░░░░┘

Creating a Zone Manually¶

Select a copper layer (e.g. F.Cu) in the Layer panel
Use the Draw Polygon tool to draw a closed polygon boundary
Assign zone properties:
- Net name (e.g. GND)
- Clearance (e.g. 0.2 mm)
- Priority (default: 0)
WireFrame computes and renders the copper fill

Zone Priority¶

When two zones overlap, the zone with the higher priority wins:

Example — VCC island inside a GND plane:

┌────────────────────────────────────────────┐
│ ░░░░░░░░░░ GND (priority 0) ░░░░░░░░░░░░ │
│ ░░░░ ┌──────────────────┐ ░░░░░░░░░░░░░░ │
│ ░░░░ │ ▓▓▓ VCC (p=1) ▓▓│ ░░░░░░░░░░░░░░ │
│ ░░░░ │   ▓▓▓▓▓▓▓▓▓▓▓   │ ░░░░░░░░░░░░░░ │
│ ░░░░ └──────────────────┘ ░░░░░░░░░░░░░░ │
└────────────────────────────────────────────┘

Priority guidelines

Ground plane → priority 0 (lowest)
VCC island inside the GND plane → priority 1
Zone nested inside VCC → priority 2, and so on

How Zones Interact with Nets¶

Situation	Result
Pad on the same net as the zone	Pad connects directly to the fill (no ratsnest)
Trace on the same net passing through	Trace connects to the zone
Pad on a different net inside the zone	Clearance gap is maintained around the pad
Trace on a different net inside the zone	Clearance gap is maintained around the trace

Editing Zones¶

Property	Editable
Net name	✅ — in Properties panel
Layer	✅
Priority	✅
Clearance	✅
Outline (vertices)	✅ — drag vertices to reshape the boundary
Cutouts	✅ — add excluded shapes inside the zone