Need explanation about settings of LevelStreaming

[Pirate_Tony]

I split and organise that to few small questions step by step. I hope answers will help to another people who confused with LevelSteaming process. So:

Question 1.

In Preferences>LevelEditor>Miscellaneous>Default Level Streaming Class

1.1. What is really difference between “LevelStreamingKismet” and “LevelStreamingPersistent”? Im not understand why has 3 options “LevelStreamingAlwaysLoaded”, “LevelStreamingKismet” and “LevelStreamingPersistent”. What means phrase “Level streaming always loaded” or this option like AlwaysLoaded in LevelEditor window ?

1.2. For what that default setting (DefaultLevelStreamingClass) is?

1.3. That setting is default setting of new added levels in LevelEditor?

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Quesion 2.

In list of Window>Levels

How setting “DefaultLevelStreamingClass” from first question affects to that 2 menu items?

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Question 3.

In settings of StreamingVolume

3.1. What is mean phrase “StreamingUsage”

3.2. What is mean word “SVB”. And how to describe of that short - Streaming Volume … ?

3.3. What is mean word “Block” or “Blocking on Load” in context of streaming process?
“Loading” is load from disk to memory buffer. Right?

3.4. What is “Loading not visible”?

3.5. What is “Visibility blocking on load”?

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Question 4.

After console command “stat levels” viewport shows list of all streaming levels like:

4.1

Colors always are red even if level show/hide in list of window-levels. Red means unloaded?

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4.2

After start game colors are green:

4.1. So grey means “persistent” / always in memory?

4.2. Green means loaded? But in that screenshot levels are not yet loaded)? Or unloaded? Or that is bug?

4.3. During play colors changes to yellow, red, blue. Yellow mean loading? Blue means unloading? What is red (in game not in the editor)?

4.4. What the difference between reds in Editor mode in viewport and red when playing game?

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Question 5.

In Preferences>LevelEditor>Play
If setting “StreamSubLevelsDuringPlay=1” then why colors does not changing. Streaming of levels works in Editor mode but color always is red.

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If anyone from stuff will answer to that questions and mark as notes/bugs then i will post some marked answers as separate reports in BugReports.

Thanks.

[Stuubo]

There is some official UE4 documentation about level streaming here: Level Streaming | Unreal Engine Documentation

[Starkium]

Docs do not answer these questions, I am also curious about all of what was asked above

[anonymous_user_c3c513d1]

for posterity and new google seekers
previous to min 2017, unloaded was shown as green, and loaded as red. Now, they are swapped, sowing some confusion.

https://github.com/EpicGames/UnrealEngine/pull/3595

from editor source 4.20.3 UnrealEngine.cpp

FColor GetColorForLevelStatus(int32 Status)
{
	FColor Color = FColor::White;
	switch (Status)
	{
	case LEVEL_Visible:
		Color = FColor::Green;		// green  loaded and visible
		break;
	case LEVEL_MakingVisible:
		Color = FColorList::Orange;	// orange, in process of being made visible
		break;
	case LEVEL_Loading:
		Color = FColor::Magenta;	// purple, in process of being loaded
		break;
	case LEVEL_Loaded:
		Color = FColor::Yellow;		// yellow loaded but not visible
		break;
	case LEVEL_UnloadedButStillAround:
		Color = FColor::Blue;		// blue  (GC needs to occur to remove this)
		break;
	case LEVEL_Unloaded:
		Color = FColor::Red;		// Red   unloaded
		break;
	case LEVEL_Preloading:
		Color = FColor::Magenta;	// purple (preloading)
		break;
	default:
		break;
	};

	return Color;
}

loaded but not visible: when streaming levels, you can mark them to be loaded, but not yet displayed. This lets you preload several levels, wait for them all to load, then mark them all visible at once (and in reverse, mark levels as invisible, then stream them out)