The simplest bridge is a wrapper around Gaea.Swarm.exe. The wrapper prepares the input files and variable values, launches the build, then imports the exported files into the host application.

This page describes the shape of that wrapper. For the full argument reference, see Command Line Automation.

1. Prepare the terrain

Build the .terrain file in Gaea first. The bridge should start from a graph that already builds successfully, with the needed outputs configured in Build Options.

Expose anything the bridge must control:

• input file paths, such as a File node's Filename property
• output paths, such as an Export node's OutputPath property
• artist controls, such as erosion amount, snowline, or mask strength
• build choices that should become Build Profiles or Regions instead of ad hoc graph edits

See Managing Input and Output for the required File and Export node setup.

2. Copy a known-good command

Open Commands and use Copy Command Line. This gives you the exact file path and current variable values for the terrain as Gaea understands them.

Use that copied command as the first working version of the bridge command before replacing values programmatically.

3. Pass bridge values with a variable file

For bridge code, --vars is usually easier to manage than a long list of inline variables. Write a JSON or text file for each run, then pass that file to Build Swarm.

{
  "InputHeightfield": "D:\\Bridge\\input\\terrain.r16",
  "OutputHeightfield": "D:\\Bridge\\output\\processed_terrain",
  "ErosionStrength": 0.45
}

The names must match variables in the .terrain file. Output paths bound to an Export node in Explicit mode should omit the extension; Gaea adds the extension from the selected export format.

4. Run Build Swarm

Use Gaea.Swarm.exe for the build step. A typical bridge command uses a terrain file plus a variable file:

Gaea.Swarm.exe --Filename "D:\Bridge\Processor.terrain" --vars "D:\Bridge\run-vars.json"

If the bridge needs a specific build setup, add the profile or region used by that workflow:

Gaea.Swarm.exe --Filename "D:\Bridge\Processor.terrain" --profile "BridgeFinal" --vars "D:\Bridge\run-vars.json"

5. Import the result

After the build finishes, the host application should check that the expected files were created before importing them. Keep the bridge's output folder predictable and unique per run, especially if multiple builds may run in parallel.

For more complex integrations, preserve the command, variable file, and build reports with the host application's logs. That makes it much easier to reproduce a failed bridge run outside the host application.