Sequencer - Blueprint AI Assistant

Level Sequencer verbs: seq-list-tracks, seq-add-track, seq-add-section, seq-add-key, seq-set-range.

Verbs for creating and editing LevelSequence assets: listing tracks, adding tracks and sections, inserting keyframes, and setting playback ranges.

seq-list-tracks#

List all tracks in a LevelSequence.

Category: Read (focused)

Arg	Required	Description
`-asset=`	Yes	LevelSequence asset path

Examples:

-verb=seq-list-tracks -asset=/Game/Cinematics/LS_Intro

seq-add-track#

Add a track to a LevelSequence.

Category: Write (sequencer)

Arg	Required	Description
`-asset=`	Yes	LevelSequence asset path
`-type=`	Yes	Track type: `Float`, `Bool`, `Transform`, `Event`, `Audio`, `SkeletalAnimation`, `CameraCut`
`-binding=`	No	Object binding name (bind the track to a specific object in the sequence)

Examples:

-verb=seq-add-track -asset=/Game/Cinematics/LS_Intro -type=CameraCut
-verb=seq-add-track -asset=/Game/Cinematics/LS_Intro -type=Transform -binding=CameraActor
-verb=seq-add-track -asset=/Game/Cinematics/LS_Intro -type=Float -binding=PointLight

Notes:

CameraCut tracks do not take a -binding= because they reference camera actors via sections/keys, not a direct object binding.
Transform and Float tracks typically bind to a specific actor so the sequencer knows which object's property to animate.

seq-add-section#

Add a section (time range) to a track.

Category: Write (sequencer)

Arg	Required	Description
`-asset=`	Yes	LevelSequence asset path
`-track=`	Yes	Track index (integer, 0-based from `seq-list-tracks` output)
`-startframe=`	Yes	Section start frame
`-endframe=`	Yes	Section end frame

Examples:

-verb=seq-add-section -asset=/Game/Cinematics/LS_Intro -track=0 -startframe=0 -endframe=150
-verb=seq-add-section -asset=/Game/Cinematics/LS_Intro -track=1 -startframe=0 -endframe=300

Notes:

Frame numbers use the sequence's display rate (typically 30 fps). A section from frame 0 to 150 at 30 fps spans 5 seconds.

seq-add-key#

Add a keyframe to a section.

Category: Write (sequencer)

Arg	Required	Description
`-asset=`	Yes	LevelSequence asset path
`-track=`	Yes	Track index (integer, 0-based)
`-frame=`	Yes	Frame number
`-value=`	Yes	Keyframe value (parsed as string, same as UE property text format)
`-section=`	No	Section index within the track (defaults to 0)
`-channel=`	No	Channel index within the section (defaults to 0). Transform tracks use channels 0-8: Location X/Y/Z (0-2), Rotation X/Y/Z (3-5), Scale X/Y/Z (6-8).

Examples:

-verb=seq-add-key -asset=/Game/Cinematics/LS_Intro -track=0 -frame=0 -value="(X=0,Y=0,Z=200)"
-verb=seq-add-key -asset=/Game/Cinematics/LS_Intro -track=0 -frame=150 -value="(X=500,Y=0,Z=200)"
-verb=seq-add-key -asset=/Game/Cinematics/LS_Intro -track=1 -frame=0 -value=0.0 -channel=0
-verb=seq-add-key -asset=/Game/Cinematics/LS_Intro -track=1 -frame=90 -value=1.0 -channel=0

Notes:

For Transform tracks, the -value= can be a full struct (X=...,Y=...,Z=...) when setting all components at once, or a single float when targeting a specific -channel=.
For Float tracks, -value= is a single numeric value.
For Bool tracks, -value= is true or false.

seq-set-range#

Set the playback range of a LevelSequence.

Category: Write (sequencer)

Arg	Required	Description
`-asset=`	Yes	LevelSequence asset path
`-startframe=`	Yes	Start frame
`-endframe=`	Yes	End frame

Examples:

-verb=seq-set-range -asset=/Game/Cinematics/LS_Intro -startframe=0 -endframe=300

Notes:

This sets the working range shown in the Sequencer editor and used as the default playback bounds.

Practical example: camera fly-through sequence#

Create a LevelSequence with a CameraCut track and a Transform track that moves a camera from one position to another over 5 seconds (150 frames at 30 fps).

Using batch (recommended)#

curl -X POST http://localhost:7850/baa/v1/batch \
  -H "Content-Type: application/json" \
  -d '{
    "defaultAsset": "/Game/Cinematics/LS_CameraFlythrough",
    "operations": [
      {
        "verb": "seq-set-range",
        "args": { "startframe": "0", "endframe": "150" },
        "id": "range"
      },
      {
        "verb": "seq-add-track",
        "args": { "type": "Transform", "binding": "CameraActor" },
        "id": "camTrack"
      },
      {
        "verb": "seq-add-section",
        "args": { "track": "$camTrack.trackIndex", "startframe": "0", "endframe": "150" },
        "id": "camSection"
      },
      {
        "verb": "seq-add-key",
        "args": {
          "track": "$camTrack.trackIndex",
          "frame": "0",
          "value": "(X=0,Y=0,Z=200)",
          "section": "0"
        }
      },
      {
        "verb": "seq-add-key",
        "args": {
          "track": "$camTrack.trackIndex",
          "frame": "75",
          "value": "(X=250,Y=100,Z=250)",
          "section": "0"
        }
      },
      {
        "verb": "seq-add-key",
        "args": {
          "track": "$camTrack.trackIndex",
          "frame": "150",
          "value": "(X=500,Y=0,Z=200)",
          "section": "0"
        }
      },
      {
        "verb": "save"
      }
    ]
  }'

Using commandlet (no HTTP server)#

# Step 1: Set playback range
"C:\Unreal\UE571Source\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" \
  "C:\Unreal\ProjectLeyline\CombatDemo\CombatDemo.uproject" \
  -run=BlueprintAIAssistant \
  -verb=seq-set-range \
  -asset=/Game/Cinematics/LS_CameraFlythrough \
  -startframe=0 -endframe=150 \
  -nullrhi -nosplash -nosound -unattended

# Step 2: Add transform track bound to camera
"C:\Unreal\UE571Source\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" \
  "C:\Unreal\ProjectLeyline\CombatDemo\CombatDemo.uproject" \
  -run=BlueprintAIAssistant \
  -verb=seq-add-track \
  -asset=/Game/Cinematics/LS_CameraFlythrough \
  -type=Transform -binding=CameraActor \
  -nullrhi -nosplash -nosound -unattended

# Step 3: Add section spanning full range
"C:\Unreal\UE571Source\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" \
  "C:\Unreal\ProjectLeyline\CombatDemo\CombatDemo.uproject" \
  -run=BlueprintAIAssistant \
  -verb=seq-add-section \
  -asset=/Game/Cinematics/LS_CameraFlythrough \
  -track=0 -startframe=0 -endframe=150 \
  -nullrhi -nosplash -nosound -unattended

# Step 4: Add start keyframe
"C:\Unreal\UE571Source\Engine\Binaries\Win64\UnrealEditor-Cmd.exe" \
  "C:\Unreal\ProjectLeyline\CombatDemo\CombatDemo.uproject" \
  -run=BlueprintAIAssistant \
  -verb=seq-add-key \
  -asset=/Game/Cinematics/LS_CameraFlythrough \
  -track=0 -frame=0 -value="(X=0,Y=0,Z=200)" \
  -save \
  -nullrhi -nosplash -nosound -unattended

Note: For the commandlet approach, prefer using the batch verb with a JSON manifest file instead of multiple separate launches. Each commandlet launch loads the full editor (30-60 seconds), so batching saves significant time.

Tips#

List tracks first. Before adding sections or keys, run seq-list-tracks to see existing track indices and types.
Use batch for multi-step operations. Building a sequence typically involves multiple verbs (add track, add section, add keys). Batch them to avoid repeated editor startup costs.
Frame numbers use display rate. The default display rate is typically 30 fps. Frame 150 = 5 seconds at 30 fps.
Channel indices for Transform tracks. Channels 0-2 are Location X/Y/Z, channels 3-5 are Rotation X/Y/Z, channels 6-8 are Scale X/Y/Z.
Save after writes. Sequencer write verbs modify the asset in memory. Use -save on the last verb or add a separate save operation to persist changes to disk.