kevinpbuckley/sound-cues

Wrong skill for MetaSound assets? If the user asked about MetaSound, MS_ assets, or UMetaSoundSource, unload this skill and load the metasounds skill instead: manage_skills(action="load", skill_name="metasounds") SoundCue and MetaSound are completely separate systems — do not use SoundCueService for MetaSound tasks.

Sound Cue Editor Skill

Service Access

import unreal
svc = unreal.SoundCueService()

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Audio Flow Direction

Audio flows FROM leaves TOWARD root.

[WavePlayer] ──> [Random] ──> [Mixer] ──> [ROOT]
                                ^
                    [WavePlayer2] ──────┘

• connect_nodes(parent, child, slot) means: child provides audio INTO parent at that input slot.
• set_root_node(index) makes that node the final output (what you hear).

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Critical Rules

⚠️ Bool Properties — b prefix stripped in Python

UE strips the b prefix from bool UPROPERTY names in Python:

| C++ / UPROPERTY | Python attribute | |-----------------|-----------------| | bSuccess | success | | bIsRootNode | is_root_node | | bLooping | is_looping | | bStreaming | is_streaming |

⚠️ Node indices are positional and may shift

list_nodes() returns nodes in graph order — indices can change if new nodes are added. Always call list_nodes() to get current indices before connecting or modifying nodes.

⚠️ connect_nodes parameter order

# parent receives audio FROM child at slot
svc.connect_nodes(cue_path, parent_index, child_index, input_slot)

# CORRECT: WavePlayer(0) feeds into Random(1) at slot 0
svc.connect_nodes('/Game/MyCue', 1, 0, 0)

# WRONG: don't confuse child/parent order

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Workflows

Create a Simple SoundCue

import unreal
svc = unreal.SoundCueService()

# Create the asset (optionally wire an initial WavePlayer)
r = svc.create_sound_cue('/Game/Audio/SC_Footstep', '')
assert r.success, r.message

# Add a WavePlayer node
r = svc.add_wave_player_node('/Game/Audio/SC_Footstep', '/Game/Audio/Footstep_01', -250, 0)
assert r.success

# Set it as the root (output)
nodes = svc.list_nodes('/Game/Audio/SC_Footstep')
svc.set_root_node('/Game/Audio/SC_Footstep', nodes[0].node_index)

# Save
svc.save_sound_cue('/Game/Audio/SC_Footstep')

Random from Multiple Waves

import unreal
svc = unreal.SoundCueService()
cue = '/Game/Audio/SC_Footsteps'

svc.create_sound_cue(cue, '')

# Add 3 wave players
for i, wave in enumerate(['/Game/Audio/Step_01', '/Game/Audio/Step_02', '/Game/Audio/Step_03']):
    svc.add_wave_player_node(cue, wave, -400, i * 150)

# Add a Random node to select one
svc.add_random_node(cue, -150, 150)

nodes = svc.list_nodes(cue)
# nodes[0..2] = WavePlayers, nodes[3] = Random
random_idx = next(i for i, n in enumerate(nodes) if 'Random' in n.node_class)
for i in range(3):
    svc.connect_nodes(cue, random_idx, i, i)  # each wave into random

svc.set_root_node(cue, random_idx)
svc.save_sound_cue(cue)

Mixer (parallel blend)

import unreal
svc = unreal.SoundCueService()
cue = '/Game/Audio/SC_Ambient'

svc.create_sound_cue(cue, '')
svc.add_wave_player_node(cue, '/Game/Audio/Wind', -400, 0)
svc.add_wave_player_node(cue, '/Game/Audio/Rain', -400, 150)
svc.add_mixer_node(cue, 2, -150, 75)   # 2 inputs

nodes = svc.list_nodes(cue)
wave0 = next(i for i, n in enumerate(nodes) if 'WavePlayer' in n.node_class and i == 0)
wave1 = next(i for i, n in enumerate(nodes) if 'WavePlayer' in n.node_class and i != wave0)
mixer = next(i for i, n in enumerate(nodes) if 'Mixer' in n.node_class)

svc.connect_nodes(cue, mixer, wave0, 0)
svc.connect_nodes(cue, mixer, wave1, 1)
svc.set_root_node(cue, mixer)
svc.save_sound_cue(cue)

Volume / Pitch / SoundClass

svc.set_volume_multiplier('/Game/Audio/SC_Explosion', 1.5)
svc.set_pitch_multiplier('/Game/Audio/SC_Explosion', 0.9)
svc.set_sound_class('/Game/Audio/SC_Explosion', '/Game/Audio/SC_SFX')

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API Reference

Asset Lifecycle

| Method | Returns | Notes | |--------|---------|-------| | create_sound_cue(path, wave_path) | FSoundCueResult | wave_path='' for empty cue | | duplicate_sound_cue(src_path, dst_path) | FSoundCueResult | copy a cue to a new path | | delete_sound_cue(path) | bool | deletes the asset from disk | | get_sound_cue_info(path) | FSoundCueInfo | node count, root index, vol, pitch, duration | | save_sound_cue(path) | bool | saves to disk |

Node Creation — all return FSoundCueResult

| Method | Node Type | Special params | |--------|-----------|---------------| | add_wave_player_node(path, wave_path, x, y) | Leaf — plays a SoundWave | wave_path optional | | add_random_node(path, x, y) | Picks one child randomly | — | | add_mixer_node(path, num_inputs, x, y) | Blends children in parallel | num_inputs 1–32 | | add_concatenator_node(path, num_inputs, x, y) | Plays children in sequence | num_inputs 2–32 | | add_modulator_node(path, x, y) | Random pitch/volume variance | — | | add_attenuation_node(path, x, y) | Spatial attenuation (graph node) | — | | add_looping_node(path, x, y) | Loops its child | — | | add_delay_node(path, x, y) | Adds a delay before playing | — | | add_switch_node(path, x, y) | Routes by integer parameter | — | | add_enveloper_node(path, x, y) | Volume/pitch envelope over time | — | | add_distance_cross_fade_node(path, num_inputs, x, y) | Crossfades by distance | num_inputs 2–32 | | add_branch_node(path, x, y, bool_param='') | Routes by bool parameter; True(0) False(1) Unset(2) | optional param name last | | add_param_cross_fade_node(path, num_inputs, x, y) | Crossfades by named float param | num_inputs 2–32 | | add_quality_level_node(path, x, y) | One input per quality level | — |

Node Management

| Method | Returns | Notes | |--------|---------|-------| | list_nodes(path) | TArray<FSoundCueNodeInfo> | index, class, children, is_root_node | | connect_nodes(path, parent, child, slot) | bool | child feeds audio INTO parent | | disconnect_node(path, parent_index, slot) | bool | break a single input link | | set_root_node(path, index) | bool | sets cue output node | | set_wave_player_asset(path, index, wave_path) | bool | reassign wave on existing node | | remove_node(path, index) | bool | delete a node from the graph | | move_node(path, index, x, y) | bool | reposition a node in the graph | | get_node_property(path, index, prop_name) | FString | read any node UPROPERTY | | set_node_property(path, index, prop_name, value) | bool | write any node UPROPERTY |

Cue-Level Settings

| Method | Returns | Notes | |--------|---------|-------| | set_volume_multiplier(path, vol) | bool | — | | set_pitch_multiplier(path, pitch) | bool | — | | set_sound_class(path, class_path) | bool | — | | set_attenuation(path, att_path) | bool | att_path='' to clear | | get_attenuation(path) | FString | returns asset path or '' | | set_concurrency(path, conc_path, clear=False) | bool | conc_path='' + clear=True to clear all | | get_concurrency(path) | TArray<FString> | list of assigned concurrency asset paths |

FSoundCueNodeInfo fields

n.node_index      # int — position in list_nodes array
n.node_class      # str — e.g. "SoundNodeWavePlayer"
n.node_title      # str — display name
n.pos_x, n.pos_y  # float — graph position
n.is_root_node    # bool — True if this node is SoundCue.FirstNode
n.child_indices   # list[int] — indices of connected children (-1 = unconnected slot)

SoundWave Utilities

| Method | Returns | Notes | |--------|---------|-------| | get_sound_wave_info(sw_path) | FSoundWaveInfo | duration, sample rate, channels, looping, streaming | | import_sound_wave(file_path, asset_path) | FSoundCueResult | import .wav/.mp3 from disk | | set_sound_wave_property(sw_path, prop, value) | bool | set any UPROPERTY by name |

Common set_sound_wave_property property names:

| PropertyName | Type | Example value | |---|---|---| | bLooping | bool | "true" | | bStreaming | bool | "true" | | VolumeMultiplier | float | "1.5" | | PitchMultiplier | float | "0.9" | | SubtitlePriority | float | "100.0" |

FSoundWaveInfo fields

info.asset_path    # str
info.duration      # float — seconds
info.sample_rate   # int — Hz
info.num_channels  # int — 1=mono, 2=stereo
info.looping       # bool  (note: NOT is_looping — UE strips the 'b' only)
info.streaming     # bool  (note: NOT is_streaming)

FSoundCueResult fields

r.success      # bool
r.asset_path   # str
r.message      # str — human-readable status or error