Location Placement Accelerator (LPA)

For a separate readme describing the config options check the github. In fact I HIGHLY recommend it.

LPA is a complete overhaul of Valheim's location placement engine, originally built to solve the massive generation times and broken unplayable worlds caused by using mods like Better Continents and Expand World Size combined with mods that add locations. Better Continents (BC hereafter) can generate incredible geology and topology and Expand World Size (EWS) can generate vast worlds, but often you cannot play in those worlds because vital locations fail to be placed during generation, and it takes forever to generate those worlds too.

When you use custom terrain noise, massive map radii, and hundreds of modded points of interest, Valheim's vanilla "guess-and-check" placement algorithm breaks down. A heavily modded game can take 30 minutes to generate a world, only to leave you with an unplayable map missing half its bosses or having no Hildir and so on.

LPA can fix this by giving the placement algorithm "eyes" (pre-scanning the world topology) and optionally (although on by default) utilizing all your CPU cores.

Note: LPA is only needed during world generation. Once your map is generated, the mod can be safely disabled or removed from your server/game. You do not need it unless you want to speed up the generation of another world.

Although the original intention was for this to be a BC feature, I realized that it can help people who do not want to use BC.

Key Features

Performance Gains: There are two kinds of performance gain. Speed and success rate. In a heavily modded setup (details later) : Total Requested: 17,391 location tokens, same seed (aabbxx)

Vanilla (deterministic)

Total Time: 27m 39.7s

Total Placed: 16,849 (96.88%)

Total Failed: 542

Survey single threaded (deterministic)

Total Time: 3m 45.0s

Total Placed: 16,935 (97.38%)

Total Failed: 456

Survey multi threaded (NON deterministic)

Total Time: 0m 36.6s

Total Placed: 16,986 (97.67%)

Total Failed: 405

The trend is:

27m 39.7s --> 3m 45.0s --> 0m 36.6s (faster)

542 --> 456 --> 405 (less failures)

Note the difference between deterministic and non deterministic:

• Deterministic means that if you use the same seed 1000 times the same locations will end up in the same exact spot, and you will place the same exact amounts.

• Non deterministic means that two runs of the same seed will differ. Multithreaded runs are non deterministic, and in most cases you should really not care about it.

The Diagnostic Logger : You can run LPA purely as a diagnostic tool in any mode. For example you could leave it in Vanilla, which would leave the vanilla placement logic intact but inject telemetry, outputting an exhaustive log of exactly what happened, and precisely why (Altitude, Distance, Biome, etc.) failed locations were rejected.

Smart Recovery (Constraint Relaxation): If a vital location (e.g., bosses, quest locations, traders) fails to spawn because the map is too crowded or the terrain is rough or whatever the reason, LPA detects the bottleneck, slightly (or as much as you want and if you want) relaxes the rules (like altitude or distance constraints) , and retries until the world is playable or fails at the relaxed cases too. You can decide how many times you want to keep relaxing. If a location that requires enough of it placed for the game to be playable (e.g. you need enough crypts for iron) then the relaxation happens (if you have it on) until it places at least 50% of the amount. The relaxation never attempts to put more than the min required. So for vital stuff it tries to place at most one, and for locations that require enough it would relax to place at most 50% of them.

EWD integration: you can add relaxableunique, relaxable, and relaxableamount keywords in your locations yaml, and design your own simple relaxation schemas.

• relaxableunique: true/false If absent from the yaml it defaults to false. If true then the relaxation will attempt to place 1 and done.
• relaxable: true/false If absent from the yaml it defaults to false. If true then the relaxation will attempt to place relaxableammount many tokens of that prefab.
• relaxableamount: takes a float e.g. 0.25 representing the percentage you want the relaxation to place If missing the default is 0.5 (50%)

Example: You could add relaxableunique: true after each prefab that is enabled in your expand_locations.yaml and the relaxation will attempt to place at least one of each location type in the game. How hard it will try to do so, depends on the settings in your config.

Interleaved Placement: This is basically a fairness mode. Vanilla places locations one type at a time. So if you have three kinds of huts, A, B and C, all wanting the same biome, it will first place all As, then all Bs, and then all Cs. This means that Cs are getting the short end of the stick, if A and B huts have captured all available spots.

This mode instead will place an A, then a B, then a C, then an A, then a B, and so on. Thus it prevents a single location type from monopolizing all the good terrain before other locations get a chance to spawn.

Parallel Minimap Generation: Generates the world map textures across multiple threads. A process that normally freezes the game for 6-10 seconds in vanilla now finishes in under ~2 seconds. (This applies to vanilla world only. See known issues about how it interacts with EWS and BC for the moment).

Compatibility

LPA should be compatible with everything and anything unless it messes with location placement.

• Better Continents
• Expand World Size (EWS)
• Expand World Data (EWD)

Fully compatible.

In fact I was writing this to add it as functionality to Better Continents especially when it is used with EWS and larger radii. It is compatible with Jere's stuff by its very inception.

It IS compatible with Riverheim but I have not used it myself.

It is not compatible with warp's World Gen Accelerator but it is very compatible with his excellent More World Locations mod which I recommend.

Compatible with all other mods that add locations that I am aware of, monsterlabz, Therzie's mods, RtD mods (if you get an older version of those), Marlthon's mods, basically should work with anything that adds locations.

Requirements

Other than bepinex you do not need anything else. EWD and through it YamlDotNet are soft requirements if you want to define your own relaxation schemas.

Known Issues

• Errors thrown by EWD are completely cosmetic and will go away when EWD updates to include the three keywords. They work and you can ignore the "error".
• LPA for now does not wait for EWS to finish generating the minimap (and EWS will cause the minimap to regenerate no matter what).
• LPA for now does not wait for stock BC to finish generating the minimap.

None of the above issues are issues for the user to care or functionality issues. Mostly issues for me.

Tips

1. Since LPA replaces the engine that vanilla uses, the numbers of location tokens that vanilla assumed to be appropriate to be given as budgets considering tons of failures would occur, now may result in overly dense in locations worlds because they will almost all be succeeding in being placed.
   So avoid the temptation to set the locations in EWS to x4 just because you doubled the area.

2. Especially if you use mods that add locations, the numbers may become too high.

3. VerboseLogFileName = true is your friend if you want to run comparative runs!

4. PresenceGridCellSize = 4 will cost more memory but will increase your success rate. So if you have the RAM... use it.

5. You basically never want to increase the outerloop. Leave it at 1.

6. You never want to increase the inner loop too much 1.25 max... more than that way too much diminishing returns....

7. increase the visit limit to 2 also something that would increase your success rate but with even worse diminishing returns.

The problem is that if you are close to 97-98% or higher... increasing those will mostly increase the time you spend (still seconds but... why) with minimal gain.

1. Setting: PlacementMode = Vanilla UseLegacyEngine = true EnableParallelPlacement = false MaxRelaxationAttempts = 0 OptimizePlacementChecks = false

will give you identical to vanilla time and success but with the diagnostic log to see what happened.

Example

The setup in the specific example was as follows: Mods that add locations:

• Therzie-Warfare-1.8.9
• Therzie-Monstrum-1.5.1
• Therzie-WarfareFireAndIce-2.0.8
• Therzie-MonstrumDeepNorth-2.0.6
• Therzie-Wizardry-1.1.8
• Therzie-Armory-1.3.1
• warpalicious-More_World_Locations_AIO-4.5.0
• Soloredis-RtDOcean-2.1.1
• Soloredis-RtDOceanFoods-0.2.0
• Soloredis-RtDMonsters-2.3.2
• Soloredis-RtDMonstrum-0.9.5
• Soloredis-RtDHorrors-0.5.2
• Soloredis-RtDDungeons-1.0.3
• Marlthon-TheFisher-0.3.5

And also using Better Continents and Expand World Size, setting the radius to 17500.

Vanilla Engine:

=================================================
===      WORLD GENERATION SUMMARY             ===
=================================================

      Total Time:       27m 39.7s
      Total Requested:  17,391
      Total Placed:     16,849  (96.88%)
      Total Failed:     542
           ----------------
            Complete failures:
            -Hildir_cave : 0/3   <-- this makes the world unplayable
            -MWL_MeadowsWall1 : 0/10
            -MWL_SwampCourtyard1 : 0/5
            -MWL_SwampBrokenTower1 : 0/15
            -MWL_SwampBrokenTower3 : 0/10
           ----------------
            Partial failures:
            -Grave1 : 135/200
            -SwampRuin2 : 28/30
            -SwampHut2 : 26/50
            -SwampHut3 : 21/50
            -StoneTowerRuins04 : 36/50
            -StoneTowerRuins05 : 5/50
            -AshlandsCave_01 : 5/7
            -AshlandsCave_02 : 4/7
            -Vegvisir_location_Vrykolathas_TW : 2/12
            -DemonPortal_TW : 1/3
            -DeepNorth_SurtrCamp_TW : 6/25
            -FortressRuins : 34/100
            -DevWallAsh : 3/5
            -VegvisirSwamp_RtD : 15/24
            -MountainAltar_RtD : 69/80
            -MistlandsAltar_RtD : 74/80
            -MWL_Ruins3 : 1/25
            -MWL_RuinsArena1 : 10/25
            -MWL_RuinsArena3 : 6/25
            -MWL_RuinsChurch1 : 9/25
            -MWL_MeadowsHouse2 : 14/20
            -MWL_MeadowsTower1 : 12/15
            -MWL_OakHut1 : 12/15
            -MWL_MeadowsLighthouse1 : 9/10
            -MWL_MeadowsSawmill1 : 1/10
            -MWL_MeadowsTavern1 : 3/10
            -MWL_RuinsTower3 : 3/15
            -MWL_RuinsTower8 : 1/10
            -MWL_ForestTower2 : 9/20
            -MWL_MassGrave1 : 9/15
            -MWL_RootRuins1 : 1/15
            -MWL_ForestTower5 : 7/15
            -MWL_SwampRuin1 : 17/25
            -MWL_AbandonedHouse1 : 9/15
            -MWL_Belmont1 : 4/5
            -MWL_StoneCircle1 : 7/10
            -MWL_SwampTemple1 : 1/10

      Playability:      UNPLAYABLE
=================================================

LPA Survey Mode (Single-Threaded):

=================================================
===      WORLD GENERATION SUMMARY             ===
=================================================

      Total Time:       3m 45.0s
      Total Requested:  17,391
      Total Placed:     16,935  (97.38%)
      Total Failed:     456
           ----------------
            Complete failures:
            -MWL_Ruins1 : 0/5
            -MWL_MeadowsRuin1 : 0/5
            -MWL_SwampGrave1 : 0/25
            -MWL_SwampCourtyard1 : 0/5
            -MWL_SwampBrokenTower1 : 0/15
           ----------------
            Partial failures:
            -Grave1 : 67/200
            -StoneTowerRuins04 : 9/50
            -StoneTowerRuins05 : 49/50
            -ShipWreck01 : 2/25
            -ShipWreck02 : 11/25
            -Vegvisir_location_Vrykolathas_TW : 10/12
            -AltarStormHerald_TW : 1/2
            -Vegvisir_location_Gorr_TW : 2/3
            -DeepNorth_SurtrCamp_TW : 6/25
            -Hildir_cave : 1/3
            -FaderLocation : 3/5
            -MWL_Ruins2 : 4/10
            -MWL_Ruins3 : 5/25
            -MWL_Ruins7 : 1/2
            -MWL_RuinsArena1 : 13/25
            -MWL_RuinsArena3 : 12/25
            -MWL_RuinsChurch1 : 18/25
            -MWL_MeadowsHouse2 : 4/20
            -MWL_MeadowsTower1 : 8/15
            -MWL_SmallHouse1 : 13/20
            -MWL_MeadowsFarm1 : 2/10
            -MWL_MeadowsLighthouse1 : 1/10
            -MWL_MeadowsSawmill1 : 2/10
            -MWL_RuinsCastle1 : 1/15
            -MWL_ForestTower2 : 9/20
            -MWL_MassGrave1 : 9/15
            -MWL_ForestTower5 : 8/15
            -MWL_SwampBrokenTower3 : 1/10
            -MWL_StoneCircle1 : 9/10

      Playability:      Playable
      -------------------------------------------------
      Relaxations Applied:
      - Hildir_cave (Relaxed 1x: MinAlt: 200->190)
=================================================

LPA Survey Mode (Multithreaded):

=================================================
===      WORLD GENERATION SUMMARY             ===
=================================================

      Total Time:       0m 36.6s
      Total Requested:  17,391
      Total Placed:     16,986  (97.67%)
      Total Failed:     405
           ----------------
            Complete failures:
            -MWL_Ruins1 : 0/5
            -MWL_RuinsCastle1 : 0/15
           ----------------
            Partial failures:
            -Grave1 : 87/200
            -SwampHut2 : 43/50
            -StoneTowerRuins04 : 9/50
            -StoneTowerRuins05 : 48/50
            -ShipWreck01 : 3/25
            -ShipWreck02 : 6/25
            -Vegvisir_location_Vrykolathas_TW : 10/12
            -DeepNorth_SurtrCamp_TW : 8/25
            -Hildir_cave : 1/3
            -MWL_Ruins2 : 1/10
            -MWL_Ruins3 : 9/25
            -MWL_Ruins7 : 1/2
            -MWL_RuinsArena1 : 6/25
            -MWL_RuinsArena3 : 10/25
            -MWL_RuinsChurch1 : 14/25
            -MWL_MeadowsHouse2 : 11/20
            -MWL_MeadowsFarm1 : 3/10
            -MWL_MeadowsLighthouse1 : 1/10
            -MWL_MeadowsSawmill1 : 3/10
            -MWL_MeadowsWall1 : 8/10
            -MWL_RuinsTower3 : 13/15
            -MWL_ForestTower2 : 10/20
            -MWL_MassGrave1 : 14/15
            -MWL_SwampGrave1 : 3/25
            -MWL_Belmont1 : 2/5
            -MWL_SwampBrokenTower1 : 4/15
            -MWL_SwampBrokenTower3 : 4/10

      Playability:      Playable
      -------------------------------------------------
      Relaxations Applied:
      - Hildir_cave (Relaxed 1x: MinAlt: 200->190)
=================================================

What you would see in the log if you have logging on:

[Warning][21:12:52.778] [FAILURE] Hildir_cave: 0/3. Cost: 4,113/200,000 outer loop budget and 82,260 inner loop iterations.
(World Altitude Profile: Min -68.0m, Max 199.6m)
────────────────────────────────────────────────────────
PHASE 1 (Zone Search): 4,113 Checks
[!] Valid Zones: 4,113
    └─ Median

PHASE 2 (Placement): 82,260 Points Sampled in the 4,113 Median zones
1. DISTANCE FILTER (Min: 1750, Max: 14000)
[x] Failed: 7
    Above Max: 7
[!] Passed: 82,253
    └─ Range 1750-14000
       |
       └─ 2. BIOME MATCH (Required: Mountain): 82,253 points checked
          [x] Failed: 35
              └─ BlackForest: 15
              └─ Plains: 10
              └─ Meadows: 7
              └─ Mistlands: 3
          [!] Passed: 82,218
              └─ Mountain
              |
              └─ 3. ALTITUDE CHECK (Min: 200, Max: 5000): 82,218 points checked
                 [x] Failed: 82,218
                     └─ Too Low: 82,218
                        └─ Mountain:
                           ├─ Underwater (<0m): 12 [Observed: Min -3.0m, Avg -1.8m, Max 0.0m]
                           ├─ Anomalous (0m to 50m): 109 [Observed: Min 0.0m, Avg 24.0m, Max 49.2m]
                           └─ Standard Failures: 82,097 [Observed: Min 52.5m, Avg 99.2m, Max 199.6m]

So in that specific instance because of the specific settings the max altitude on the map was not 200, (which is what Hildir needed) and thus all 82,218 attempts failed. However, by relaxing the requirements the world is saved:

[Info][21:14:58.763] [LPA] Relaxation pass 1: processing 1 relaxed packet(s).
[Message][21:14:59.385] [RELAXATION SUCCESS] Hildir_cave placed 1/1 after 1 relaxation(s). (Relaxed 1x: MinAlt: 200->190)
[Message][21:14:59.386] [RELAXED] Hildir_cave: 1/1. Cost: 763/200,000 outer loop budget and 15,243 inner loop iterations.
           (Relaxed 1x: MinAlt: 200->190)
(World Altitude Profile: Min -68.0m, Max 199.6m)
────────────────────────────────────────────────────────
PHASE 1 (Zone Search): 763 Checks
[!] Valid Zones: 763
    └─ Median

PHASE 2 (Placement): 15,243 Points Sampled in the 763 Median zones
1. DISTANCE FILTER (Min: 1750, Max: 14000)
[!] Passed: 15,243
    └─ Range 1750-14000
       |
       └─ 2. BIOME MATCH (Required: Mountain): 15,243 points checked
          [x] Failed: 7
              └─ Meadows: 5
              └─ Plains: 2
          [!] Passed: 15,236
              └─ Mountain
              |
              └─ 3. ALTITUDE CHECK (Min: 190, Max: 5250): 15,236 points checked
                 [x] Failed: 15,235
                     └─ Too Low: 15,235
                        └─ Mountain:
                           ├─ Anomalous (0m to 50m): 57 [Observed: Min 0.9m, Avg 29.7m, Max 49.3m]
                           └─ Standard Failures: 15,178 [Observed: Min 50.3m, Avg 95.2m, Max 182.2m]
                 [!] Passed: 1
                     └─ Alt 190 to 5250
                     └─ PASSED REMAINING CHECKS (SIMILARITY -> TERRAIN DELTA -> VEGETATION DENSITY): 1

Since it was detected than altitude was the problem the altitude was relaxed by 5% (so 200 became 190) and we looked again, successfully placing the location.

Installation

1. Install via your mod manager or drop the .dll into your BepInEx/plugins folder.

2. Launch the game and generate your world. By default, Parallel Placement and Smart Recovery are enabled.

3. Check the LocationPlacementAccelerator.log in your BepInEx folder to verify your world is playable.

4. (Optional) Disable or remove the mod. You only need it when creating a new world or forcing new location generation. It simply does not do anything otherwise.

You can find me and ask for help on Discord at the Valheim World Editing server: https://discord.gg/uqY4V8Aw .

You can find the source code on github.

You can find yet another readme that explains what is going on behind the scenes on github too. It is a work in progress at the moment