ue-world-level-streaming

Name: ue-world-level-streaming
Author: quodsoler

548installs39forks

How to install ue-world-level-streaming?

quodsoler/unreal-engine-skills/ue-world-level-streaming

$npx -y skills add quodsoler/unreal-engine-skills --skill ue-world-level-streaming

Installs into the current project.

Summary

Use this skill when working with World Partition, level streaming, level travel, OpenLevel, ServerTravel, data layer, world subsystem, level instance, sub-level, seamless travel, open world, or HLOD. See references/streaming-patterns.md for configuration patterns by game type.

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SKILL.md

1	# UE World & Level Streaming
2
3	You are an expert in Unreal Engine's world management and level streaming systems.
4
5	---
6
7	## Context
8
9	Read `.agents/ue-project-context.md` before advising. Pay attention to:
10	- Engine version — World Partition is UE5 only; sub-level streaming works in both UE4 and UE5.
11	- Build targets — Dedicated server has no rendering-driven streaming; streaming must be server-safe.
12	- World size — Determines whether World Partition or manual sub-level streaming is appropriate.
13	- Multiplayer — Seamless travel requirements and per-player streaming radius.
14
15	---
16
17	## Information to Gather
18
19	Before recommending a streaming approach, confirm:
20
21	1. World size and type: Is this an open world (World Partition), a set of discrete levels, or a hub-and-spoke map?
22	2. Multiplayer: Are you running a dedicated server? Are per-player streaming radii needed?
23	3. Streaming control: Does gameplay code need to control load/unload explicitly, or should proximity drive it?
24	4. Level travel: Non-seamless (lobby flows), seamless (multiplayer round transitions), or no travel?
25	5. Persistent data: What must survive a level transition — player state, inventory, session state?
26
27	---
28
29	## World Partition (UE5)
30
31	### Enabling World Partition
32
33	Enable via the Level menu: World -> World Partition -> Convert Level. Once enabled, all actors in the level are managed by World Partition's grid. The level can no longer have traditional sub-levels. Use One File Per Actor (OFPA) for collaborative editing: each actor is saved as its own `.uasset` under `__ExternalActors__`.
34
35	### Runtime Data Layers
36
37	Data layers replace the old sub-level toggle pattern. A runtime data layer can be loaded/unloaded at runtime without traveling to a new map.
38
39	```cpp
40	// MyGameMode.cpp
41	#include "WorldPartition/DataLayer/DataLayerManager.h"
42
43	void AMyGameMode::ActivateDungeonDataLayer()
44	{
45	UDataLayerManager* DLMgr = UDataLayerManager::GetDataLayerManager(GetWorld());
46	if (!DLMgr) return;
47
48	// Get by asset reference (set up in editor as a UDataLayerAsset)
49	UDataLayerAsset* DungeonLayer = DungeonDataLayerAsset.LoadSynchronous();
50	DLMgr->SetDataLayerRuntimeState(DungeonLayer, EDataLayerRuntimeState::Activated);
51	}
52
53	void AMyGameMode::DeactivateDungeonDataLayer()
54	{
55	UDataLayerManager* DLMgr = UDataLayerManager::GetDataLayerManager(GetWorld());
56	if (!DLMgr) return;
57
58	UDataLayerAsset* DungeonLayer = DungeonDataLayerAsset.LoadSynchronous();
59	DLMgr->SetDataLayerRuntimeState(DungeonLayer, EDataLayerRuntimeState::Unloaded);
60	}
61	```
62
63	Data layer states:
64	- `Unloaded` — not loaded, not visible.
65	- `Loaded` — loaded into memory, not visible (pre-warming).
66	- `Activated` — loaded and visible (fully active).
67
68	### Streaming Sources
69
70	Each player controller is a streaming source by default. For custom sources (cinematic cameras, AI directors), implement `IWorldPartitionStreamingSourceProvider`.
71
72	### HLOD
73
74	HLOD provides distant merged-mesh representations of World Partition cells. Configure HLOD layers in the World Partition editor; build before shipping via Build -> Build World Partition HLODs. Without HLOD, content beyond the streaming radius is simply absent.
75
76	### Converting Sub-Levels to World Partition
77
78	Use Tools -> World Partition -> Convert Level. Actors migrate into the persistent level under WP management. Audit cross-level references beforehand — hard references to converted actors become invalid.
79
80	### World Partition and Multiplayer
81
82	In a multiplayer session, each player controller acts as a streaming source with a configurable radius. The server streams based on server-side sources; clients receive visibility updates via `AServerStreamingLevelsVisibility`. On dedicated servers, rendering-based streaming does not apply — streaming is driven by server-side sources only.
83
84	Streaming radius is configured per-partition in the World Partition editor UI (`LoadingRange` on `URuntimePartition`), not via ini.
85
86	---
87
88	## Level Streaming (Manual Sub-Levels)
89
90	### ULevelStreaming State Machine
91
92	From `LevelStreaming.h`, the full state sequence is:
93
94	```
95	Removed -> Unloaded -> Loading -> LoadedNotVisible -> MakingVisible -> LoadedVisible -> MakingInvisible -> LoadedNotVisible
96	\|
97	FailedToLoad (check logs; level asset missing or corrupt)
98	```
99
100	Query state with:
101
102	```cpp
103	ULevelStreaming* StreamingLevel = /* ... */;
104	ELevelStreamingState State = StreamingLevel->GetLevelStreamingState();
105
106	switch (State)
107	{
108	case ELevelStreamingState::Unloaded: /* not in memory */ break;
109	case ELevelStreamingSta

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ue-world-level-streaming

548installs39forks

View on GitHub

How to install ue-world-level-streaming?

quodsoler/unreal-engine-skills/ue-world-level-streaming

$npx -y skills add quodsoler/unreal-engine-skills --skill ue-world-level-streaming

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# UE World & Level Streaming
2
3	You are an expert in Unreal Engine's world management and level streaming systems.
4
5	---
6
7	## Context
8
9	Read `.agents/ue-project-context.md` before advising. Pay attention to:
10	- Engine version — World Partition is UE5 only; sub-level streaming works in both UE4 and UE5.
11	- Build targets — Dedicated server has no rendering-driven streaming; streaming must be server-safe.
12	- World size — Determines whether World Partition or manual sub-level streaming is appropriate.
13	- Multiplayer — Seamless travel requirements and per-player streaming radius.
14
15	---
16
17	## Information to Gather
18
19	Before recommending a streaming approach, confirm:
20
21	1. World size and type: Is this an open world (World Partition), a set of discrete levels, or a hub-and-spoke map?
22	2. Multiplayer: Are you running a dedicated server? Are per-player streaming radii needed?
23	3. Streaming control: Does gameplay code need to control load/unload explicitly, or should proximity drive it?
24	4. Level travel: Non-seamless (lobby flows), seamless (multiplayer round transitions), or no travel?
25	5. Persistent data: What must survive a level transition — player state, inventory, session state?
26
27	---
28
29	## World Partition (UE5)
30
31	### Enabling World Partition
32
33	Enable via the Level menu: World -> World Partition -> Convert Level. Once enabled, all actors in the level are managed by World Partition's grid. The level can no longer have traditional sub-levels. Use One File Per Actor (OFPA) for collaborative editing: each actor is saved as its own `.uasset` under `__ExternalActors__`.
34
35	### Runtime Data Layers
36
37	Data layers replace the old sub-level toggle pattern. A runtime data layer can be loaded/unloaded at runtime without traveling to a new map.
38
39	```cpp
40	// MyGameMode.cpp
41	#include "WorldPartition/DataLayer/DataLayerManager.h"
42
43	void AMyGameMode::ActivateDungeonDataLayer()
44	{
45	UDataLayerManager* DLMgr = UDataLayerManager::GetDataLayerManager(GetWorld());
46	if (!DLMgr) return;
47
48	// Get by asset reference (set up in editor as a UDataLayerAsset)
49	UDataLayerAsset* DungeonLayer = DungeonDataLayerAsset.LoadSynchronous();
50	DLMgr->SetDataLayerRuntimeState(DungeonLayer, EDataLayerRuntimeState::Activated);
51	}
52
53	void AMyGameMode::DeactivateDungeonDataLayer()
54	{
55	UDataLayerManager* DLMgr = UDataLayerManager::GetDataLayerManager(GetWorld());
56	if (!DLMgr) return;
57
58	UDataLayerAsset* DungeonLayer = DungeonDataLayerAsset.LoadSynchronous();
59	DLMgr->SetDataLayerRuntimeState(DungeonLayer, EDataLayerRuntimeState::Unloaded);
60	}
61	```
62
63	Data layer states:
64	- `Unloaded` — not loaded, not visible.
65	- `Loaded` — loaded into memory, not visible (pre-warming).
66	- `Activated` — loaded and visible (fully active).
67
68	### Streaming Sources
69
70	Each player controller is a streaming source by default. For custom sources (cinematic cameras, AI directors), implement `IWorldPartitionStreamingSourceProvider`.
71
72	### HLOD
73
74	HLOD provides distant merged-mesh representations of World Partition cells. Configure HLOD layers in the World Partition editor; build before shipping via Build -> Build World Partition HLODs. Without HLOD, content beyond the streaming radius is simply absent.
75
76	### Converting Sub-Levels to World Partition
77
78	Use Tools -> World Partition -> Convert Level. Actors migrate into the persistent level under WP management. Audit cross-level references beforehand — hard references to converted actors become invalid.
79
80	### World Partition and Multiplayer
81
82	In a multiplayer session, each player controller acts as a streaming source with a configurable radius. The server streams based on server-side sources; clients receive visibility updates via `AServerStreamingLevelsVisibility`. On dedicated servers, rendering-based streaming does not apply — streaming is driven by server-side sources only.
83
84	Streaming radius is configured per-partition in the World Partition editor UI (`LoadingRange` on `URuntimePartition`), not via ini.
85
86	---
87
88	## Level Streaming (Manual Sub-Levels)
89
90	### ULevelStreaming State Machine
91
92	From `LevelStreaming.h`, the full state sequence is:
93
94	```
95	Removed -> Unloaded -> Loading -> LoadedNotVisible -> MakingVisible -> LoadedVisible -> MakingInvisible -> LoadedNotVisible
96	\|
97	FailedToLoad (check logs; level asset missing or corrupt)
98	```
99
100	Query state with:
101
102	```cpp
103	ULevelStreaming* StreamingLevel = /* ... */;
104	ELevelStreamingState State = StreamingLevel->GetLevelStreamingState();
105
106	switch (State)
107	{
108	case ELevelStreamingState::Unloaded: /* not in memory */ break;
109	case ELevelStreamingSta

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