Layer Maps

Layer maps define how layers are renamed, renumbered, merged, or filtered during conversion. They are especially useful when converting between formats with different layer conventions (e.g., GDSII numeric layers to DXF named layers).

LinkCAD supports two layer map file formats: JSON (recommended) and CSV.

JSON Format

JSON layer maps use a schema-validated format with richer metadata. This is the recommended format for new projects.

{
  "$schema": "https://schema.linkcad.com/layer-map-v1-schema.json",
  "version": 1,
  "units": "um",
  "layer_map": [
    {
      "input_layer": "METAL1",
      "output_layer": "M1",
      "order": 1,
      "comment": "Metal 1 layer",
      "color": "#FF0000",
      "visibility": true,
      "elevation": 1000,
      "thickness": 500,
      "material": 3,
      "extrude": true
    },
    {
      "input_layer": "VIA1",
      "output_layer": "V1",
      "order": 2,
      "color": "Blue",
      "stack": true,
      "thickness": 200
    }
  ]
}

Root Fields

Field	Required	Description
$schema		Schema URL for editor validation
version		Schema version (must be 1)
units		Unit for elevation and thickness values — nm, pm, um, mil, point, mm, cm, in, m, ft
layer_map	yes	Array of layer mapping entries

Entry Fields

Field	Required	Type	Description
input_layer	yes	string	Source layer identifier
output_layer		string	Target layer identifier
order		integer	Display order (JSON only — not available in CSV)
comment		string	Description or note
color		string	Layer color — hex (#FF0000) or X11 name (Red)
visibility		boolean	Whether the layer is visible
elevation		number	Z-coordinate, scaled by units (not allowed when stack is true)
thickness		number	Layer thickness, scaled by units
material		integer	Material index
extrude		boolean	Whether to extrude this layer in 3D export
stack		boolean	Stack layers automatically (mutually exclusive with elevation)

Tip

The JSON format supports order for controlling layer display order, which is not available in CSV layer maps.

CSV Format

CSV layer maps are plain-text files with comma or semicolon delimiters. Each row defines one layer mapping.

Columns

#	Column	Description
1	input_layer	Source layer identifier (required)
2	output_layer	Target layer identifier
3	comment	Description or note
4	color	Layer color — hex or X11 name
5	visibility	true or false
6	elevation	Z-coordinate in database units (picometers)
7	material	Material index
8	extrude	true or false
9	stack	true or false
10	thickness	Layer thickness in database units

Example

METAL1,M1,Metal 1 layer,#FF0000,true,1000,3,true,false,500
VIA1,V1,,Blue,true,,,,false,200
POLY,P1,,#FFFF00,,,,,,

Fields may be quoted. Both comma and semicolon separators are accepted.

JSON vs. CSV

Feature	JSON	CSV
order field	yes	no
Unit scaling for elevation/thickness	yes	no (always picometers)
Schema validation	yes	no
Structured metadata	yes	no

Merging Layers

Map multiple source layers to the same target to merge them:

1,METAL
2,METAL
3,METAL

Filtering Layers

Only layers listed in the map are included in the output. Unlisted layers are dropped.

Using Layer Maps

GUI

1. Load a layer map from the Layer Map panel
2. Assign mappings by editing the table
3. Apply during conversion

Command Line

linkcad.exe -i chip.gds -o chip.dxf `
  --layer-map mapping.csv --apply-layer-map --quit

Python

import linkcad.plugin as lp

# Layer maps can be applied programmatically in tool plugins

Tips

• Layer maps can be created from the GUI and saved as CSV for reuse
• Use consistent layer naming conventions across projects
• The map file encoding should be UTF-8
• See Layers for more on layer management