Scene Building

Scene & World Building Workflow

Core Pattern: Observe → Execute → Verify

1. Observe — scene_brief for level overview, scene_query for specific actors, search_assets for meshes/materials
2. Execute — scene_compose for batch placement, domain tools for specific systems
3. Verify — scene_query with spatial filters to confirm, pie_test_scene for runtime behavior

Scene Queries & Placement

Finding Things

• scene_brief — compact level overview (actor counts, classes, bounds)
• scene_query — find actors by class/label/tag/folder with spatial filters (near, box, frustum)
• search_assets — Content Browser search by name/prefix/class (returns asset paths, NOT actor labels)
• asset_references — dependency graphs (what does X reference, what references X)
• project_context — engine version, plugins, project settings, maps, content stats

Scene tools work on actors (placed instances). search_assets works on assets (reusable files). Never confuse the two.

Placing Things

scene_compose declaratively spawns/modifies/deletes actors with prefabs + patterns. Prefer it over looping scene_query writes.

Actor Management

• actor_inspect — drill into one actor (components, properties, transform)
• Use scene_compose to modify transforms, delete actors, or batch-manage scene objects

Landscape & Terrain

Inspection

landscape_inspect — height/slope/normal queries, statistics, find flat areas, paint-layer listing.

Editing

landscape_edit handles:

• Lifecycle — create/resize/delete landscapes
• Sculpting — raise, lower, smooth, flatten, erosion
• Semantic features — mountains, valleys, craters, plateaus, terraces
• Paint layers — create and apply landscape material layers
• Heightmap — import/export

Always inspect before editing to understand current terrain state.

Foliage

• foliage_inspect — list types + counts
• foliage_edit — create FoliageTypes, scatter (circles/rectangles/by weight layer), place exact transforms, remove by radius or type

Materials & Shading

1. material_inspect — read-only (overview, expressions, connections, parameters, textures, shader stats, parent chain). Run BEFORE material_edit on existing materials.
2. material_edit — create materials/instances/functions/Parameter Collections, author expression graphs. Auto-retries single-input pin name resolution.

VFX (Niagara & Chaos)

• niagara_inspect → niagara_edit for systems/emitters/parameters/renderers
• niagara_script_edit for reusable NiagaraScript module graphs
• chaos_edit for Geometry Collections (fracture, clustering, damage thresholds)
• ramp_authoring for curve assets (UCurveFloat/Vector/LinearColor) — create the curve FIRST, then reference from the consumer

AI & Behavior Trees

Full setup workflow:

1. behavior_tree with create_blackboard → create keys (TargetActor, PatrolLocation, etc.)
2. behavior_tree with create_behavior_tree → create the BT asset
3. behavior_tree with set_blackboard_on_bt → link Blackboard to BT
4. behavior_tree with build_behavior_tree → build tree structure (selectors, sequences, tasks, decorators)
5. behavior_tree with create_ai_controller → create controller referencing the BT
6. behavior_tree with validate_behavior_tree → validate

Also covers: AI perception, NavMesh, EQS queries, StateTrees, Smart Objects, runtime BT + blackboard inspection in PIE.

Gameplay Abilities

• gas_edit — Gameplay Abilities (tags, cost, cooldown, activation), Effects (duration, modifiers, stacking), Attribute Sets
• tag_registry_edit — project-wide Gameplay Tag hierarchy

Cinematics

sequencer_edit creates Level Sequences with:

• Actor bindings
• Transform / animation / audio / camera / event / fade tracks
• Keyframes with interpolation control
• Camera cuts

Audio

• metasound_edit — procedural audio (MetaSound graphs: oscillators, filters, envelopes, mixers, sample players)
• sound_asset_edit — SoundCue graphs, SoundClass hierarchy, SoundAttenuation curves

Procedural Content

pcg_graph_edit — PCG graphs with point generators, samplers, filters, density operators, mesh spawners with typed pin wiring.

Physics

collision_profile_edit — collision profiles, physical materials, object type responses.

Editor Utilities

• editor_actions — save, undo, redo, select, focus, build lighting/navigation, compile, PIE start/stop, viewport mode
• editor_log — Output Log + Message Log with verbosity filter + time window
• performance_audit — triangle counts, actor counts by class, mesh complexity, texture memory, optimization warnings
• window_capture — viewport screenshot as PNG

Runtime Verification

pie_test_scene — free-tier PIE harness with:

• Narrow input whitelist (console, wait, spawn_actor, play_sequence, fire_damage)
• Lifecycle + VFX + audio + visual-regression assertions
• Auto-plan mode from task description

Use after any scene change that affects runtime behavior.

Data Assets

asset_factory — single entry for:

• Enums / Structs
• DataTables (CRUD rows, bulk JSON import)
• DataAssets (any subclass)
• Enhanced Input (IA + IMC + key mappings + modifiers + triggers)
• Safe Blueprint deletion (crash-safe path)