🧠 Brains complement: IF an unreal-engine-skills-manager tool (external MCP) exists in this session, call it with {action: "load", skill: "actors-and-components"} for UE domain knowledge on this topic — correct APIs, architecture, best practices — and treat it as the rubric for any review / "best practices" question. If no such tool is available (e.g. running under Claude Code or Codex without that MCP), skip this line entirely and proceed with this skill alone — do NOT attempt the call.

Level Actors Skill

🔀 Engine owns the basics now. In the Unreal 5.8 consolidation, listing / finding / spawning / moving / transforming / selecting actors moved to Unreal's native toolsets — ActorTools, SceneTools, and EditorAppToolset (selection, camera, PIE, screenshots), reachable via call_tool. Equivalently you can drive unreal.EditorActorSubsystem / unreal.LevelEditorSubsystem directly from execute_python_code (shown throughout below). VibeUE's ActorService was trimmed to only the delta the engine doesn't provide: transform lock (set_actor_lock_location), absolute-transform flags, preserve-scale-ratio, viewport camera framing (get_actor_view_camera / calculate_actor_view / set_viewport_camera), and full property dumps (get_all_properties). ActorService.add_actor / set_property / get_property no longer exist — use the engine toolsets or EditorActorSubsystem for spawning and property edits.

Critical Rules

� Creating a "Basic" Level Requires new_level_from_template, NOT new_level

When the user asks to create a new level (especially "Basic", "Default", or with a sky/floor), always use new_level_from_template:

subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
# ❌ WRONG — creates a completely empty level with no content
subsys.new_level("/Game/Maps/MyLevel")

# ✅ CORRECT — creates level with floor, sky, lighting, player start
subsys.new_level_from_template("/Game/Maps/MyLevel", "/Engine/Maps/Templates/Template_Default")

Template names: Template_Default = Basic, OpenWorld, TimeOfDay_Default, VR-Basic

---

�🚫 DEPRECATED: unreal.EditorLevelLibrary

DO NOT use unreal.EditorLevelLibrary. The entire Editor Scripting Utilities Plugin is deprecated in UE 5.7+. Use unreal.EditorActorSubsystem via unreal.get_editor_subsystem() for all level actor operations.

# ❌ DEPRECATED - DO NOT USE
all_actors = unreal.EditorLevelLibrary.get_all_level_actors()
unreal.EditorLevelLibrary.spawn_actor_from_class(...)

# ✅ CORRECT - Use EditorActorSubsystem
actor_subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
all_actors = actor_subsys.get_all_level_actors()
actor_subsys.spawn_actor_from_class(...)

🚫 get_all_level_actors_of_class DOES NOT EXIST

EditorActorSubsystem has NO get_all_level_actors_of_class() method. Always use get_all_level_actors() + isinstance() filtering:

# ❌ WRONG - This method does not exist, causes AttributeError
actor_subsys.get_all_level_actors_of_class(unreal.Landscape)

# ✅ CORRECT - Filter manually
landscapes = [a for a in actor_subsys.get_all_level_actors() if isinstance(a, unreal.Landscape)]
lights = [a for a in actor_subsys.get_all_level_actors() if isinstance(a, unreal.PointLight)]

🚨 Verified AttributeError traps (UE 5.7 Python) — don't burn iterations rediscovering these

You might write	❌ Why it fails	✅ Use instead
comp.get_static_mesh()	StaticMeshComponent has no get_static_mesh	comp.get_editor_property("static_mesh") (read) / comp.set_static_mesh(mesh) (write)
actor.get_components()	Actors have no get_components()	actor.get_components_by_class(unreal.StaticMeshComponent) → array
dir_light.directional_light_component	no such attribute	dir_light.light_component (ALL unreal.Light actors use light_component)
comp.set_editor_property("cast_shadow", …)	property is plural	comp.set_editor_property("cast_shadows", False)
unreal.HorizontalTextAligment	UE misspells it	unreal.HorizTextAligment / unreal.VerticalTextAligment (for TextRenderActor)

When unsure of a property/method name, call discover_python_class(class_name="unreal.X") ONCE up front rather than guessing repeatedly — its doc_string lists the real editor-property names.

Migration guide:

Deprecated (EditorLevelLibrary)	Replacement (EditorActorSubsystem)
get_all_level_actors()	actor_subsys.get_all_level_actors()
get_all_level_actors_of_class(cls)	[a for a in actor_subsys.get_all_level_actors() if isinstance(a, cls)]
spawn_actor_from_class()	actor_subsys.spawn_actor_from_class()
destroy_actor()	actor_subsys.destroy_actor()
get_selected_level_actors()	actor_subsys.get_selected_level_actors()
set_actor_selection_state()	actor_subsys.set_actor_selection_state()

🚨 Spawn Static Mesh Actors via spawn_actor_from_class + comp.set_static_mesh()

Do not spawn a bare actor and then poke StaticMesh through a generic property setter — that historically produced actors with zero-extent bounds (invisible in the viewport even though the mesh reads back as set). (The old ActorService.add_actor / set_property helpers that caused this were removed in 5.8.)

ALWAYS use spawn_actor_from_class + comp.set_static_mesh():

import unreal

actor_subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
mesh = unreal.load_asset("/Engine/BasicShapes/Cube")
material = unreal.load_asset("/Game/Materials/M_MyMat")

actor = actor_subsys.spawn_actor_from_class(
    unreal.StaticMeshActor,
    unreal.Vector(0, 0, 100),
    unreal.Rotator(0, 0, 0)
)
actor.set_actor_label("MyMeshActor")
actor.set_actor_scale3d(unreal.Vector(2, 2, 2))

comp = actor.static_mesh_component
comp.set_static_mesh(mesh)
comp.set_material(0, material)   # Optional

# Verify it has real bounds (not 0,0,0)
bounds = actor.get_actor_bounds(False)
print(f"Bounds extent: {bounds[1].x:.0f}, {bounds[1].y:.0f}, {bounds[1].z:.0f}")

If bounds extent is 0, 0, 0 after spawning, the mesh was not applied correctly.

⚠️ Get Subsystem Instance First

import unreal

actor_subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
level_subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)

⚠️ Spawning Actors - Use Class Object, NOT Path String

# For built-in classes
actor = subsys.spawn_actor_from_class(unreal.StaticMeshActor, location, rotation)

# For Blueprint classes - load first
bp_class = unreal.EditorAssetLibrary.load_blueprint_class("/Game/BP_Enemy")
actor = subsys.spawn_actor_from_class(bp_class, location, rotation)

⚠️ FVector and FRotator Objects Required

# CORRECT
location = unreal.Vector(100, 200, 0)
rotation = unreal.Rotator(pitch=-45)  # ALWAYS use keyword args for Rotator (see rule below)

# WRONG - strings don't work
location = "(X=100,Y=200,Z=0)"

🚨 Constructor Argument Order Traps: Rotator is (Roll, Pitch, Yaw), Color is BGRA

The Python constructors do NOT use the order you expect. Always use keyword arguments — never positional — for unreal.Rotator and unreal.Color:

# ❌ WRONG — Rotator positional order is (Roll, Pitch, Yaw), NOT (Pitch, Yaw, Roll)
unreal.Rotator(-45, 0, 0)        # sets ROLL=-45, not pitch!

# ✅ CORRECT — keyword args, unambiguous
unreal.Rotator(pitch=-45)                    # angle down 45°
unreal.Rotator(roll=0, pitch=-90, yaw=45)    # straight down, spun 45°

# ❌ WRONG — Color positional order is (B, G, R, A), NOT (R, G, B, A)
unreal.Color(255, 180, 100)      # comes out BLUE, not warm orange!

# ✅ CORRECT — keyword args, or use LinearColor (which IS r, g, b, a positional)
unreal.Color(r=255, g=180, b=100, a=255)
unreal.LinearColor(1.0, 0.7, 0.4, 1.0)       # LinearColor positional is normal RGBA

Pitch sign convention: negative pitch = downward (pitch=-90 points straight down). For lights/cameras use negative pitch to aim at the ground.

⚠️ Refresh Viewport After Changes

level_subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
level_subsys.editor_invalidate_viewports()

---

Workflows

Create Level from Template

🚨 Critical: new_level() creates a blank/empty level with NO content (no floor, sky, lights, or player start). To get the standard "Basic" level with default content, ALWAYS use new_level_from_template() with /Engine/Maps/Templates/Template_Default.

Available UE 5.7 templates in /Engine/Maps/Templates/:

Template path	Description
/Engine/Maps/Templates/Template_Default	Basic — floor, sky sphere, directional light, player start
/Engine/Maps/Templates/OpenWorld	Open world with large terrain
/Engine/Maps/Templates/TimeOfDay_Default	Time-of-day sky setup
/Engine/Maps/Templates/VR-Basic	VR template

Pattern: Create a new level from the Basic template

import unreal

subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
save_path  = "/Game/Maps/MyLevel"
template   = "/Engine/Maps/Templates/Template_Default"

# new_level_from_template: closes current level, creates from template, saves + loads
result = subsys.new_level_from_template(save_path, template)
print(f"Created: {result}")  # True on success

⚠️ Cannot delete the currently-loaded level. If the target path already exists and is loaded, you must first switch away using new_level() to a temp path, then create from template:

import unreal

subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
target   = "/Game/Maps/MyLevel"
template = "/Engine/Maps/Templates/Template_Default"

# 1. Switch to temp level to unload target (so it can be overwritten)
subsys.new_level("/Game/Maps/__TempSwitch")

# 2. Create the actual level from template (overwrites any existing asset at target)
result = subsys.new_level_from_template(target, template)
print(f"Created from template: {result}")
# Note: __TempSwitch is automatically replaced/closed — no manual cleanup needed

---

Save the Current Level (Save / Save As)

Getting the editor world — it lives on UnrealEditorSubsystem, NOT LevelEditorSubsystem, NOT the deprecated EditorLevelLibrary:

import unreal

# ❌ WRONG — AttributeError: 'LevelEditorSubsystem' object has no attribute 'get_editor_world'
unreal.get_editor_subsystem(unreal.LevelEditorSubsystem).get_editor_world()

# ❌ DEPRECATED — Editor Scripting Utilities plugin
unreal.EditorLevelLibrary.get_editor_world()

# ✅ CORRECT
world = unreal.get_editor_subsystem(unreal.UnrealEditorSubsystem).get_editor_world()

Which save call to use:

• Level already saved at a path → unreal.get_editor_subsystem(unreal.LevelEditorSubsystem).save_current_level()
• Untitled/never-saved level, or "save as <new name>" → EditorLoadingAndSavingUtils.save_map(world, asset_path) (both args required, in that order):

import unreal

world = unreal.get_editor_subsystem(unreal.UnrealEditorSubsystem).get_editor_world()
ok = unreal.EditorLoadingAndSavingUtils.save_map(world, "/Game/Maps/MyLevel")
print(f"Saved: {ok}")

To also make the saved level the editor startup map, load the project-settings skill and set maps / EditorStartupMap with the full asset path (/Game/Maps/MyLevel.MyLevel).

---

Spawn Built-in Actor

import unreal

subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
actor = subsys.spawn_actor_from_class(
    unreal.StaticMeshActor,
    unreal.Vector(0, 0, 100),
    unreal.Rotator(0, 0, 0)
)

level_subsys = unreal.get_editor_subsystem(unreal.LevelEditorSubsystem)
level_subsys.editor_invalidate_viewports()

Spawn Blueprint Actor

import unreal

subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
bp_class = unreal.EditorAssetLibrary.load_blueprint_class("/Game/Blueprints/BP_Enemy")
if bp_class:
    actor = subsys.spawn_actor_from_class(bp_class, unreal.Vector(500, 0, 100), unreal.Rotator(0, 0, 0))

Get Level Actors

⚠️ unreal.EditorLevelLibrary is DEPRECATED. Always use EditorActorSubsystem instead.

import unreal

actor_subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
all_actors = actor_subsys.get_all_level_actors()
lights = [a for a in all_actors if isinstance(a, unreal.PointLight)]

for actor in all_actors[:10]:
    loc = actor.get_actor_location()
    print(f"{actor.get_name()} at ({loc.x}, {loc.y}, {loc.z})")

Transform Operations

import unreal

# Get/Set location — args: (new_location, sweep, teleport)
loc = actor.get_actor_location()
actor.set_actor_location(unreal.Vector(100, 200, 300), False, False)

# Get/Set rotation — ALWAYS keyword args for Rotator (positional is Roll, Pitch, Yaw!)
rot = actor.get_actor_rotation()   # rot.pitch / rot.yaw / rot.roll
actor.set_actor_rotation(unreal.Rotator(pitch=-90, yaw=45), False)

# Relative rotation in LOCAL space (returns HitResult — see sweep section)
actor.add_actor_local_rotation(unreal.Rotator(pitch=30), False, False)
# World-space equivalent: actor.add_actor_world_rotation(...)

# Get/Set scale
scale = actor.get_actor_scale3d()
actor.set_actor_scale3d(unreal.Vector(2, 2, 2))

# Everything at once
actor.set_actor_transform(
    unreal.Transform(
        location=unreal.Vector(500, 500, 200),
        rotation=unreal.Rotator(pitch=45),
        scale=unreal.Vector(1.5, 1.5, 1.5)),
    False, False)

Sweep Moves & Collision Checks (HitResult)

Three verified gotchas (UE 5.7):

1. HitResult fields cannot be read as attributes — hit.blocking_hit / hit.bBlockingHit raise "property is protected". Use hit.to_tuple()[0] (the blocking-hit bool) or hit.export_text() (full readable dump: Location, ImpactPoint, Normal, Distance, Time).
2. set_actor_location(loc, sweep=True, ...) does NOT detect collisions in the editor world — it reports no hit even when moving straight through another actor. Don't rely on it for collision checks.
3. The definitive checks: compare the actor's final position to the target, and/or trace the path explicitly with SystemLibrary.line_trace_single (this DOES hit editor actors):

import unreal

actor.set_actor_location(target, True, False)
# ⚠️ Vector.equals(b) takes NO tolerance arg — use distance() for tolerant compare
arrived = unreal.Vector.distance(actor.get_actor_location(), target) < 1.0

# Explicit path check that actually works in the editor:
world = unreal.get_editor_subsystem(unreal.UnrealEditorSubsystem).get_editor_world()
hit = unreal.SystemLibrary.line_trace_single(
    world, start_loc, target,
    unreal.TraceTypeQuery.ECC_VISIBILITY,      # Visibility channel (TRACE_TYPE_QUERY1 is the deprecated alias)
    False, [actor],                            # ignore the moving actor itself
    unreal.DrawDebugTrace.NONE, True)
if hit and hit.to_tuple()[0]:                  # [0] = blocking hit bool
    blocker = hit.to_tuple()[9]                # [9] = hit Actor, [10] = hit Component
    print(f"Blocked by {blocker.get_actor_label()}: {hit.export_text()[:200]}")

Organize: Rename, Folders, Attach/Detach, Tags

import unreal

# Rename (the label shown in the outliner)
actor.set_actor_label("MainLight")

# Outliner folder (creates the folder if needed; "" = root, "A/B" nests)
actor.set_folder_path("TestLights")

# Attach to another actor, keeping current world position
actor.attach_to_actor(parent_actor, "",
    unreal.AttachmentRule.KEEP_WORLD,
    unreal.AttachmentRule.KEEP_WORLD,
    unreal.AttachmentRule.KEEP_WORLD, False)

# Detach, keeping world position
actor.detach_from_actor(
    unreal.DetachmentRule.KEEP_WORLD,
    unreal.DetachmentRule.KEEP_WORLD,
    unreal.DetachmentRule.KEEP_WORLD)

# Actor tags (read/write the whole list; query with `in`)
actor.tags = ["Test", "Lighting"]
tagged = [a for a in actor_subsys.get_all_level_actors() if "Lighting" in a.tags]

Light Actors (PointLight, SpotLight, DirectionalLight)

All unreal.Light actors expose their component as actor.light_component — no get_component_by_class needed:

import unreal

comp = light_actor.light_component        # PointLightComponent / SpotLightComponent / ...
comp.set_intensity(10000)
comp.set_light_color(unreal.LinearColor(1.0, 0.7, 0.4))   # warm; LinearColor IS positional RGBA
intensity = comp.get_editor_property("intensity")
# Spot cone angles (SpotLight only):
# comp.set_inner_cone_angle(20); comp.set_outer_cone_angle(35)

Selection

import unreal

subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
subsys.select_nothing()  # Clear
subsys.set_actor_selection_state(actor, True)  # Select
selected = subsys.get_selected_level_actors()  # Get selected

Move Actor to Viewport Camera

import unreal

actor_subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)
editor_subsys = unreal.get_editor_subsystem(unreal.UnrealEditorSubsystem)

camera_info = editor_subsys.get_level_viewport_camera_info()
if camera_info:
    cam_loc, cam_rot = camera_info
    forward_vec = cam_rot.get_forward_vector()
    new_loc = cam_loc + (forward_vec * 200.0)
    actor.set_actor_location(new_loc, False, True)

Destroy/Duplicate Actors

import unreal

subsys = unreal.get_editor_subsystem(unreal.EditorActorSubsystem)

# Destroy
subsys.destroy_actor(actor)

# Duplicate
dup = subsys.duplicate_actor(actor)
loc = dup.get_actor_location()
dup.set_actor_location(unreal.Vector(loc.x + 200, loc.y, loc.z), False, False)

Camera View Methods (for screenshots and verification)

Use ActorService to position the viewport camera to frame actors from specific directions. (For a plain "focus on these actors" with no specific direction, the engine EditorAppToolset FocusOnActors action via call_tool also works — ActorService adds the directional/padding framing the engine toolset lacks.)

⚠️ NEVER guess camera coordinates with set_viewport_camera. Manual positions almost always point at sky or empty space. Always use get_actor_view_camera which auto-calculates position from the actor's bounding box.

import unreal

actor_service = unreal.ActorService

# Move camera to view an actor from above (top-down)
view = actor_service.get_actor_view_camera("MyLandscape", unreal.ViewDirection.TOP)

# Move camera to view from front with extra padding
view = actor_service.get_actor_view_camera("MyBuilding", unreal.ViewDirection.FRONT, 1.5)

# Calculate view without moving camera
view = actor_service.calculate_actor_view("MyActor", unreal.ViewDirection.RIGHT, 1.2)
# view.camera_location, view.camera_rotation, view.view_distance

Directions: TOP, BOTTOM, LEFT, RIGHT, FRONT, BACK Padding: 1.0=tight, 1.2=default, 2.0=far, 3.0=very far (use for large structures)

Choosing the Right View

Goal	Use
Overview of a large structure	TOP with padding 2.0–3.0
See the front face	FRONT with padding 1.5–2.5
Full castle/building view	FRONT padding 3.0, or TOP padding 2.5
Check layout from above	TOP padding 1.5
Profile view	LEFT or RIGHT

⚠️ Do NOT switch to set_viewport_camera with manual coordinates to get a "better angle". Manual positions almost always miss the subject and point at sky or empty space. If the view isn't wide enough, increase the padding or switch to TOP. There is no need for a diagonal camera — TOP and FRONT with adequate padding cover every screenshot use case.

---

Transform Locking & Constraints

🔒 Location Locking (Per-Actor, Native UE5)

UE5 has a native bLockLocation property on all actors. When locked, the actor cannot be moved via viewport gizmos (but CAN still be moved via code).

import unreal

# Lock an actor's location
unreal.ActorService.set_actor_lock_location("MyCube", True)

# Check if locked
locked = unreal.ActorService.get_actor_lock_location("MyCube")
print(f"Locked: {locked}")

# Unlock
unreal.ActorService.set_actor_lock_location("MyCube", False)

🔒 Scale Ratio Lock (Uniform Scaling Padlock — Global Editor Setting)

The padlock icon next to Scale in the Details panel is the Preserve Scale Ratio setting. When enabled, scaling any axis scales ALL axes proportionally. This is a global editor preference, not per-actor.

import unreal

# Lock scale axes together (uniform scaling) — the padlock icon
unreal.ActorService.set_preserve_scale_ratio(True)

# Unlock for independent axis scaling
unreal.ActorService.set_preserve_scale_ratio(False)

# Check current state
locked = unreal.ActorService.get_preserve_scale_ratio()
print(f"Scale ratio locked: {locked}")

⚠️ There is NO Per-Actor Rotation or Scale Lock

UE5 does NOT have a per-actor lock for rotation or scale. There is no bLockRotation or bLockScale property on actors. Only location locking (set_actor_lock_location) is per-actor.

If user asks to "lock rotation" or "lock scale on this actor specifically":

1. Explain this limitation clearly
2. For uniform scaling, use set_preserve_scale_ratio(True) (global, affects all actors)
3. For location locking, use set_actor_lock_location
4. For world-space independence, use absolute transform flags

Absolute Transform Flags (Per-Component)

Make location/rotation/scale world-space instead of relative to parent. Useful when attaching actors but needing independent positioning.

import unreal

# Make rotation absolute (independent of parent), keep location/scale relative
unreal.ActorService.set_absolute_transform("MyCube", False, True, False)

# Check flags
loc, rot, scale = unreal.ActorService.get_absolute_transform("MyCube")
print(f"Absolute: loc={loc}, rot={rot}, scale={scale}")

Sample scripts (run via execute_python_code)

• scripts/manipulate_actors.txt — list level actors, find by class, move/rotate by name.