Dimension Separator

This mod is created to separate what can appear in wich dimension. Tested on Minecraft 1.20.1 with Forge 47.1.3+.

What does it do?

I wanted to make a RP server where all the "magic" was forbiden in the overworld for lore purposes but I struggled to prevent some structures to appear in the overworld while still be in my custom dimension.

So I tried to create a mod to help me just do that.

It's still in testing but you can use a simple json config to tell the mod what exactly you want to let appear in wich dimension.

For each dimension, you can blacklist or whitelist mod namespaces to block:

World generation features (ores, plants, structures...)
Mob spawning
Loot tables (chests, mob drops...)
Item usage (right-click on blocks, in the air, or on entities)
Structure generation

Configuration

The config file is located at config/dimensionseparator.json.~~~~ Here is an example :

{
    "dimensions": {
        "minecraft:overworld": {
            "mode": "blacklist",
            "bypassLevel": 2,
            "namespaces": ["ars_nouveau", "iceandfire"],
            "blacklistedIds": ["minecraft:zombie"],
            "whitelistedIds": ["ars_nouveau:bookwyrm_familiar"],
            "features": true,
            "mobs": true,
            "loot": true,
            "items": true,
            "structures": true
        }
    }
}

Fields

Field	Type	Description
`mode`	string	`"blacklist"` to block listed mods, `"whitelist"` to allow only listed mods
`bypassLevel`	int	Minimum operator level allowed to `/summon` blocked entities (-1 or absent = no bypass)
`namespaces`	string array	Mod IDs to block or allow depending on `mode`
`blacklistedIds`	string array	Specific IDs always blocked, regardless of `mode` (e.g. `"minecraft:zombie"`)
`whitelistedIds`	string array	Specific IDs always allowed, regardless of `mode` (e.g. `"ars_nouveau:bookwyrm_familiar"`)
`features`	boolean	Block world generation features (ores, plants...) from listed mods
`mobs`	boolean	Block mob spawning from listed mods
`loot`	boolean	Block loot tables from listed mods (chests, mob drops...)
`items`	boolean	Block item usage (right-click) from listed mods
`structures`	boolean	Block structure generation from listed mods

Setting a category to false disables blocking for that category, even if the namespace is listed.

Known Limitations

/locate on a blocked structure will search indefinitely without result. This is vanilla Minecraft behavior when no matching structure exists in the dimension.
Client-side keybinds (e.g. opening a mod's GUI with a custom key) are not blocked — only right-click interactions are covered. In practice, opening an interface without being able to interact with the dimension is harmless.
Item usage via custom keybinds is client-side and cannot be intercepted server-side.

Compatibility

This mod uses Mixins and event handlers and should be compatible with most Forge mods. If you encounter a conflict, please open an issue.

Issues & Contributions

Found a bug or have a suggestion? Open an issue on GitHub.