Layer Maps

A layer map controls how layers are translated between input and output formats. It lets you rename layers, change colors, set visibility, define 3D properties, and filter which layers are exported.

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 — 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

Each row maps one input layer. Columns are comma-separated, with no header row:

input_layer,output_layer,comment,color,visibility,elevation,material,extrude,stack,thickness

Column Reference

Column	Type	Description
input_layer	string	Layer name or number from the imported file
output_layer	string	Layer name or number for the exported file
comment	string	Comment to apply to the exported layer
color	color	Display color — hex RGBA (#rrggbbaa) or color name (Blue, Red, etc.)
visibility	bool	Whether the layer is exported (true/false, 1/0, on/off)
elevation	real	Bottom Z-value for 3D export, in picometers
material	integer	Material identifier for 3D export
extrude	bool	Whether the layer is extruded in 3D
stack	bool	Stack this layer on top of the one below (mutually exclusive with elevation)
thickness	real	Layer thickness for 3D export, in picometers

Note

Strings containing commas must be quoted: "Metal 1, upper". Boolean values accept 1/0, true/false, or on/off.

Example

1,,,Blue,true,,,false,true,10000000000
2,,,Yellow,true,,,false,true,5000000000
3,,,Magenta,true,,,false,true,5000000000
4,,,Cyan,true,,,false,true,5000000000
5,,,"#ffc000",true,,,false,true,5000000000
6,,,"#ff00cc",true,,,false,true,10000000000

This maps GDSII layers 1–6 with custom colors, all visible, stacked with specified thicknesses.

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

Using a Layer Map

In the GUI

1. In the export options, check Apply Layer Map
2. Click Browse and select your .csv file
3. Proceed with export — the mapping is applied automatically

From the Command Line

linkcad.exe -i design.gds -o output.dxf `
  --layer-map LayerMap.csv --apply-layer-map

Legacy CLI Syntax

linkcad -LcApplyLayerMap=true -LcLayerMap="LayerMap.csv"

Tips

• Omit columns you don’t need — trailing commas are fine: 1,Metal1,,Blue,true
• Set visibility to false to suppress a layer during export without deleting it
• For 3D export, elevation and thickness are always in picometers (10⁻¹² meters)
• Use stack=true for layers that should be placed on top of the previous layer instead of at an absolute elevation