Modding:WorldGen Concept

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This article introduces how world generation is handled in Vintage story, and the extent to which it can be modded. It is also intended as a general introduction for modding endeavors in regards to world generation.


Important terminology to note while reading this article:

  • Chunk: An data structure that holds 32x32x32 blocks. It is of note that chunks do not span the world height.
  • Chunk column: A set of chunks spanning the vertical height of the world. Given a world height of 256, a chunk column would represent 8 vertically stacked chunks
  • Map chunk: A data structure that holds information on a chunk column, such as the rain height or snow accumulation
  • Map Region: A data structure that holds information over an area of 16x16 chunk columns, such as weather and maps required for world generation


World generation is the process of generating necessary data about the world when the player requires it. World generation is done on a region, map chunk and chunk column basis - each acting as a meaningful subdivision of the world. Each region, map chunk and chunk column is only generated once and stores important data about that area. World generation is very modular. Almost all generated parts of the world, such as ore deposits, creatures or trees, are specified via JSON content mods. On a coding level, each stage of generation triggers an event which the base game registers handlers to. Event handlers can be registered or removed through the API to alter any part of generation.

Content modding

Using content modding, here are the various things that can be added, modified or removed from world generation. Properties relative to world generation are generally located at Vintagestory/assets/survival/worldgen

Moddable content

Item Description
Deposits Anything that is "deposited" in the ground on generation, such as ores or patches of blocks like gravel and chalk
Structures Pre-defined structures, such as the ruins found throughout. The "How to use WorldEdit" page has instructions on building and exporting structures
Trees Tree and shrub placement
Block layers Layers of blocks found above the rock layer
Block patches Patches of blocks, also vegetation
Geological provinces Geological attributes and placement
Landforms Land layout and the general arrangement of terrain

Code modding

Using code modding, it is possible to remove any specific part of world generation from the base game entirely, as well as add new functionality.

World types

There are currently three world types - "standard", "superflat", "empty". World types exist under EnumWorldGenPreset. World type has to be specified when registering event handlers for world generation.


The chunk column generation event is additionally subdivided into passes. Passes are essentially layers in the generation of a chunk column - first laying down the rock layer in one pass, and doing more general cross-chunk actions in later passes, such as flooding them with light or growing patches of grass. Passes exist under EnumWorldGenPass. The pass has to be specified when registering event handlers for chunk column generation.

Index Name Description Requires neighbor chunks
0 None Nothing generated yet false
1 Terrain Basic terrain, rock strata, caves, block layers false
2 TerrainFeatures Deposits, structures, ponds true
3 Vegetation Block patches, shrubbery and trees, rivulets, sunlight flooding in chunk true
4 NeighbourSunLightFlood Snow layer, sunlight flooding to nearby chunks true
5 PreDone Done generating, spawn creatures, neighbor chunks might still generate additional things true
6 Done Pass is not triggered as an event -


The generation of either a region (IMapRegion), map chunk (IMapChunk), or chunks contained in that chunk column (IServerChunk and IWorldChunk), triggers an event (in that order). Each of these interfaces holds some specific data about the given region. It is possible to register handlers to events, wherein access is provided for the given interface. The order in which the handlers are assigned is based on the execute order of their specific mod systems.

Accessing events

class Mod : ModSystem
    public override double ExecuteOrder()
        // Make sure all delegates have been assigned
        return 10;

    public override void StartServerSide(ICoreServerAPI api)
        // Get the handler for interacting with world generation.
        IWorldGenHandler handler = api.Event.GetRegisteredWorldGenHandlers("standard");

        // Example registering events using a delegate.
        api.Event.ChunkColumnGeneration(/* Handler here */, EnumWorldGenPass.None, "standard");
        api.Event.MapChunkGeneration(/* Handler here */, "standard");
        api.Event.MapRegionGeneration(/* Handler here */, "standard");

        // Retrieving registered handlers.
        List<MapChunkGeneratorDelegate> onMapChunkGen = handler.OnMapChunkGen;
        List<ChunkColumnGenerationDelegate>[] onChunkColGen = handler.OnChunkColumnGen;
        List<MapRegionGeneratorDelegate> onMapRegionGen = handler.OnMapRegionGen;

        foreach (var deleg in onMapChunkGen)
            // Printing class name of delegate instance.
            // This can be useful for finding and removing any particular event from the list.

Green Items require C# coding

Getting Started | Basic Examples | Theme Pack

Asset System | Textures | Items | Recipes | Blocks | Entities | Model Creator | Animation Basics | VTML & Icons | Packaging & Release | Modinfo | Debugging


JSON Patching | Advanced JSON Item | The Remapper | Server-Client Considerations | Compatibility with other mods

Setting up your Development Environment

Advanced Blocks | Advanced Items | Block and Item Interactions | Block Behavior | Block Entity | Particle Effects | World Access | Inventory Handling | Commands | GUIs | Network API | Monkey patching (Harmony)

Data Management

Savegame Data Storage | ModConfig File | Chunk Data Storage | TreeAttribute


WorldGen Concepts | Terrain | Ores | Trees | WorldGen API | NatFloat | EvolvingNatFloat | Json Random Generator


Shaders and Renderers

Property Overview

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Workflows & Infrastructure

Modding Efficiency Tips | Mod-engine compatibility | Mod Extensibility | VS Engine

Additional Resources

List of server commands | List of client commands | Client startup parameters | Server startup parameters | Creative Starter Guide | ServerBlockTicking | Bot System | WorldEdit | Cinematic Camera | Adjustable FPS Video Recording

Example Mods | API Docs | GitHub Repository