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PolyMc-Extra

Automatically patch mods so that regular players don't need to install mods to join your server!

Fabric
Loaders
Fabric
Downloads on Modrinth
1.1K
Followers on Modrinth
4
versions
6
Updated
May 23, 2026May 23
Published
in 2026
This is a library — other mods need it, and it adds nothing to the game by itself

At a glance

A library: other mods need it
Runs on Fabric
For Minecraft 1.21.6–1.21.8, 1.21.10–26.1.2
Server only — players don't need to install it
Latest version — BETA+26.1.2+1.0.5 from May 23, 2026
Requires Polymer
Where it's needed
In gamenot neededOn serverrequired

Install on the server only; players don't need it

Game versions1.21.6–1.21.8, 1.21.10–26.1.2

PolyMc-Extra

This is a server-side library and a tool for providing automatic patching mods for PolyMc. It functions similarly to PolyMc but is more powerful. It enables automatic patching of certain mods, and its patching functionality can be controlled by modifying configuration files.

The following registry entries were processed by the patch

List: Attribute, EntityType, SoundEvent, ComponentType, EnchantmentEffectComponentType, EnchantmentLocationBaseEffectType, EnchantmentEntityEffectType, StatusEffect, Potion, ScreenHandlers, ConsumeEffectType, StatType, CustomStat, PoiType, ItemGroup, Item, Block, BlockEntityType, Profession

Runtime Lifecycle:

  1. Register the built-in ExtraModelType
  2. Register Special Entity Mappings
  3. Scan and execute all module's "polymc-extra" entry points (PolyMcExtraEntrypoint.class)
  4. Before all static registry entries freeze: Read the configuration file, iterate through the registry, and patch each missing item (server-only)
  5. Verify item components integrity
  6. Scan for required resources in JAR files and generate resource packages

For player/server owners/mod pack makers:

It can automatically repair the state of corresponding polymer blocks for most mods, allowing Vanilla clients to join servers with mods.

For mod developers:

It provides several APIs and tools for developers to patch complex mods; for others, you can ask questions on Discord.

Knowledge required

You should first learn how to use some libraries.

Development Environment

  1. Create a libs folder in your module project directory.
  2. Download the JAR file and place it in the libs folder in your module project directory.
  3. Add the following content to build.gradle:
repositories {
    maven { url "https://maven.nucleoid.xyz" }
    maven { url "https://maven.tomalbrc.de" }
    maven { url "https://api.modrinth.com/maven" }
    maven { url "https://maven.architectury.dev/" }
    maven {
        url "https://maven.theepicblock.nl"
        content { includeGroup("nl.theepicblock") }
    }
    flatDir {
        dirs 'libs'
    }
}
dependencies {
    modImplementation("eu.pb4:polymer-core:[${polymer_version}]")
    modImplementation("eu.pb4:polymer-blocks:[${polymer_version}]")
    modImplementation("eu.pb4:polymer-resource-pack:[${polymer_version}]")
    modImplementation("eu.pb4:polymer-resource-pack-extras:[${polymer_version}]")
    modImplementation("eu.pb4:polymer-virtual-entity:[${polymer_version}]")
    modImplementation("eu.pb4:polymer-autohost:${polymer_version}")
    modImplementation("eu.pb4:polymer-networking:[${polymer_version}]")
    modImplementation("nl.theepicblock:resource-locator-api:${project.resource_locator_version}")
    modImplementation("eu.pb4:factorytools:[${factorytools_version}]")
    modImplementation("eu.pb4:sgui:[${sgui_version}]")
    modImplementation("xyz.nucleoid:server-translations-api:${server_translation_api_version}")
    
    modImplementation files('libs/PolyMc-Extra-XXXXXXX.jar')
    modCompileOnly 'maven.modrinth:polydex:XXXXXX'
}

Patch Code Example

public class PolymerifyRegistry implements PolyMcExtraEntrypoint {

    @Override
    public void onInitialize() {
        PolymerifyRegistry.initialize();
        PolyMcExtraPacks.NAMESPACES.add(getNamespace());
    }
    
    public static void initialize() {
        registerPolymerBlock(BlockRegistry.XXX, XXXPolymerBlock.INSTANCE);
        registerPolymerItem(BlockRegistry.XXX, new PolymerItemImpl(BlockRegistry.XXX.asItem()));
    }

    public static void registerPolymerBlock(Block block, PolymerBlock polymerBlock) {
        ResourceLocation key = BuiltInRegistries.BLOCK.getKey(block);
        PolymerBlock.registerOverlay(block, polymerBlock);
        if (polymerBlock instanceof BlockWithElementHolder elementHolder) {
            BlockWithElementHolder.registerOverlay(block, elementHolder);
        }
        PolyMcExtra.LATE_INIT.add(new Runnable() {
            @Override
            public void run() {
                if (PolymerBlockHelper.testJsonExist(block)) {
                    BlockStateModelManager.addBlock(key, block);
                }
            }
        });
    }

    public static void registerPolymerItem(ItemLike item, PolymerItem polymerItem) {
        PolymerItem.registerOverlay(item.asItem(), polymerItem);
    }
    
    @Override
    public String getNamespace() {
        return MOD_ID;
    }
}

public class XXXPolymerBlock {
    public static final BlockState OVERLAY_0 = PolymerBlockResourceUtils.requestEmpty(BlockModelType.ACTIVE_PRESSURE_PLATE);
    public static final BlockState OVERLAY_1 = PolymerBlockResourceUtils.requestEmpty(BlockModelType.KELP_BLOCK);
    public static final BaseFactoryBlock INSTANCE = new BaseFactoryBlock(OVERLAY_0, false, BlockStateModel::midRange) {
        @Override
        public BlockState getPolymerBlockState(BlockState state, PacketContext context) {
            if (state.hasProperty(BlockStateProperties.WATERLOGGED) && state.getValue(BlockStateProperties.WATERLOGGED)) {
                return OVERLAY_1;
            }
            return super.getPolymerBlockState(state, context);
        }
    };
}

Example Config:

The configuration file is located at /config/polymc-extra.json

{
    "DisabledOpaqueBlocks": [],
    "CustomBlockModelTypeMappings": {
        "citymod:stone_table": "BLOCK_DISPLAY_ENTITY",
        "citymod:road_block": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_yellow": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_yellow_connect": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_white_connect": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_yellow_double": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_zebra_crossing": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:roadblock_oblique": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:roadblock_yellow_oblique": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:roadblock_double_oblique": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:zebracrossing_oblique": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_straight": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "citymod:road_diamond": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:modern_light": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:computer_mouse": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:black_mirror": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:laptop": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:modern_clock": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:led_floor_lamp": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:shower": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:portable_laptop_stand": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:laptop_closed_portable_laptop_stand": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:cooktop": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:keyboard": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:monitor_setup": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:shower": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:socket": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:modern_chair": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "js_furniture_mod:wood_chair": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "^js_furniture_mod:midi_.+$": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "^js_furniture_mod:.*": "BLOCK_DISPLAY_ENTITY",
        "^skniro_furniture:.*_(drawer|cabinet|fridge|kitchen_sink|oven|tv_stand)$": "BLOCK_DISPLAY_ENTITY",
        "^skniro_furniture:.*_(bed|cushion|sofa|window(?:_style.*)?|plate|chair(?:_.*)?|lamp)$": "BLOCK_DISPLAY_ENTITY_NO_COLLISION",
        "^skniro_furniture:.*_window(_.*)?$": "CLOSEABLE_BLOCK",
        "^skniro_furniture:.*_(door)$": "CLOSEABLE_BLOCK",
        "^skniro_furniture:.*_glass_table": "BLOCK_DISPLAY_ENTITY",
        "terrestria:cattail": "WATER_PLANT",
        "terrestria:andisol_grass_block": "POLYMER:BIOME_TRANSPARENT_BLOCK",
        "^storagedelight:.*$": "BLOCK_DISPLAY_ENTITY",
        "^terrestria:.*_log$": "BLOCK_DISPLAY_ENTITY"
    },
    "CustomEntityModelMappings": {
        "js_furniture_mod:chair_entity": "polymc-extra:chair",
        "js_furniture_mod:sofa_entity": "polymc-extra:chair",
        "skniro_furniture:chair_entity": "polymc-extra:chair",
        "skniro_furniture:sofa_entity": "polymc-extra:chair",
        "skniro_furniture:cushion_entity": "polymc-extra:chair",
        "citymod:explode_bow_projectile": "minecraft:arrow",
        "citymod:rifle_legacy_projectile": "minecraft:arrow"
    },
    "CustomModelExpansionMappings": {
        "js_furniture_mod:sofa": 0.0,
        "js_furniture_mod:wood_light_table": 0.0,
        "js_furniture_mod:led_floor_lamp_rgb_off": 0.0,
        "js_furniture_mod:led_floor_lamp_rgb_off_2": 0.0,
        "js_furniture_mod:studio_light": 0.0,
        "citymod:road_block": 0.0,
        "citymod:road_yellow": 0.0,
        "citymod:road_yellow_connect": 0.0,
        "citymod:road_white_connect": 0.0,
        "citymod:road_yellow_double": 0.0,
        "citymod:road_zebra_crossing": 0.0
    }
}

Commands

  • /polymc-extra:

    • export-extra-block-models-mappings: Export the PolyMc-processed block map to ExtraBlockMapping.txt
    • get-all-model-types: Showing all block mapping types
    • get-client-state: Showing the true mapping and overlay mapping of the square the crosshair is pointing at.
    • get-item-info: Showing the real ID of the item in your hand and its component information.

What this library/mod doesn't do

It does not support client-side rendering.

If the module uses ASM to modify certain enums or replaces Vanilla's registry entries, it will cause some abnormal errors.

License

This mod is partially based on code from enderscape-patch and PolyMc that are licensed with GNU Lesser General Public License v3.0 and GNU Lesser General Public License 3.0

FAQ

How to install PolyMc-Extra?

Install Fabric for your Minecraft version, download PolyMc-Extra for the same version and loader, put the file into the mods folder and launch the game with the loader profile.

Which Minecraft versions does PolyMc-Extra support?

PolyMc-Extra has builds for Minecraft 1.21.6–1.21.8, 1.21.10–26.1.2.

Is PolyMc-Extra needed on the server?

Server only — players don't need to install it

License and source
GNU General Public License v3.0 onlyfree to use and share; changes to the mod itself must be published under the same license
Original — Modrinth↗Files unchanged, verified with SHA-512Is this your mod? For rights holders

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