Project file

A Showmesh project is a JSON-formatted .imsn file. The engine loads, normalises, migrates, and saves it using atomic writes and a journal.

Top-level structure

{
  "schemaVersion": 1,
  "name": "My show",
  "resources": [],
  "outputs": [],
  "connections": [],
  "triggers": [],
  "cueLists": [
    { "id": "main", "name": "Main", "cues": [] }
  ]
}

Field	Contents
schemaVersion	Document schema version; not the protocol revision
resources	Media and text sources
outputs	Display, NDI, Spout, or null outputs
connections	Currently OSC output connections
triggers	MIDI Note/CC transport mappings
cueLists	Cue lists; the editor currently uses the first list

Minimal video cue with an action

{
  "id": "cue-video",
  "number": "1",
  "name": "Opening video",
  "type": "video",
  "target": "res-video",
  "playMode": "onceHold",
  "preWait": 0,
  "postWait": 0,
  "continueMode": "none",
  "durationSec": 0,
  "actions": [
    {
      "id": "fade-in",
      "type": "transition",
      "property": "video.opacity",
      "from": 0,
      "to": 1,
      "durationMs": 1000,
      "curve": "sCurve",
      "trigger": { "type": "onPlay" }
    }
  ]
}

An empty action target means the owning cue.

Safe editing

1. Prefer the editor; the engine is the only document writer.
2. Stop the engine before unavoidable hand editing.
3. Make a copy.
4. Keep IDs unique and do not rename parameter IDs.
5. Validate JSON syntax.
6. Open in Showmesh, inspect migration warnings, and save under a new name.
7. Rehearse the entire show.

Migration

On load, the engine converts legacy fadeInSec, fadeOutSec, tracks[], and completionAction data into visible actions where possible. Migration is idempotent. A legacy track with a relative destination may remain on the old execution path.