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

Load a layer map from the Layer Map panel
Assign mappings by editing the table
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