Motivations of Gaia — Worldgen V2 Prefab Integration (Hytale)

This repository contains the Motivations of Gaia mod for Hytale.
This README documents, in detail, how we got a custom Prefab (the Orb Temple) to naturally generate using Hytale Worldgen V2. The information below is based on real debugging in a live mod project and is meant to be a reliable, reproducible guide for other creators.

If you are new to Hytale’s worldgen assets, this will save you hours.

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Quick Summary (The Fix)

The prefab wasn’t spawning because the Prefab path in the Assignment asset pointed to a folder-like path instead of the actual prefab file.
Hytale logged:

This prefab path contains no prefabs: MotivationsOfGaia/Structures/OrbTemple/OrbTemple

Correct path (note the .prefab.json extension):

MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json

After rebuilding the mod JAR, the prefab spawned naturally during world generation.

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Project Structure (Relevant Files)

Key assets used for Worldgen V2 prefab spawning:

• Prefab asset
  src/main/resources/Server/Prefabs/MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json

• Assignment asset (spawner logic)
  src/main/resources/Server/HytaleGenerator/Assignments/OrbTemple_Assignments.json

• Biome overrides (hook the assignment into Plains biomes)
  src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_Oak.json
src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_Shore.json
src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_Mountains.json
src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_Deeproot.json
src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_Gorges.json
src/main/resources/Server/HytaleGenerator/Biomes/Plains1/Plains1_River.json

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How We Implemented Natural Prefab Spawning

1. Create the Prefab

We created a prefab called OrbTemple and stored it here:

Server/Prefabs/MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json

This is the actual file that must be referenced by the worldgen assignment.

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2. Build a Worldgen Assignment Asset

We created a custom Assignment that points to our prefab:

File: Server/HytaleGenerator/Assignments/OrbTemple_Assignments.json

Inside it, the prefab is referenced via WeightedPrefabPaths:

"WeightedPrefabPaths": [
  {
    "Path": "MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json",
    "Weight": 10
  }
]

Important: The path must resolve to an actual prefab file.
Do not omit the .prefab.json extension unless you are pointing at a folder of prefabs.

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3. Attach the Assignment to Biomes

We injected the assignment into the Plains biome variants using the Props section.
Example from Plains1_Oak.json:

"Props": [
  {
    "Skip": false,
    "Runtime": 0,
    "Positions": {
      "Type": "Occurrence",
      "Seed": "OrbTemple",
      "FieldFunction": {
        "Type": "Constant",
        "Value": 0.01
      },
      "Positions": {
        "Type": "Mesh2D",
        "PointGenerator": {
          "Type": "Mesh",
          "ScaleX": 300,
          "ScaleY": 300,
          "ScaleZ": 300,
          "Jitter": 0.2
        }
      }
    },
    "Assignments": {
      "Type": "Imported",
      "Name": "OrbTemple_Assignments"
    }
  }
]

This is how the prefab gets natural placement, not forced / manually spawned.

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Debugging Process (What Actually Broke It)

Symptom

The prefab never appeared, no errors, and worldgen looked normal.

Log Clue

In the server log:

This prefab path contains no prefabs: MotivationsOfGaia/Structures/OrbTemple/OrbTemple

Root Cause

The path in the assignment was interpreted as a folder, and the engine found no prefabs there.
Hytale expects:

• A folder path ending in / that contains prefabs
  • Example: Monuments/Unique/Mage_Towers/Sandstone/Tier_3/
• Or a full prefab file path
  • Example: MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json

Our original path didn’t match either case, so it silently failed.

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Verification (How We Confirmed the Fix)

After updating the path, we verified the mod JAR contained the correct assignment:

Server/HytaleGenerator/Assignments/OrbTemple_Assignments.json
Path = MotivationsOfGaia/Structures/OrbTemple/OrbTemple.prefab.json

The prefab then spawned naturally in the world.

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Practical Tips for Reliable Spawning

If you’re not seeing your prefab yet, try these short-term debugging settings:

• Increase spawn chance:
  • FieldFunction.Value from 0.01 → 0.5
• Increase mesh density:
  • ScaleX/ScaleY/ScaleZ from 300 → 75

Once you confirm it works, scale those values back down.

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Build & Deploy

This project builds its JAR directly into the Hytale Mods folder.

Output directory (from pom.xml):

${user.home}/.var/app/com.hypixel.HytaleLauncher/data/Hytale/UserData/Mods

After every change:

1. Build the mod
2. Restart worldgen / recreate the test world
3. Check the latest log for prefab-path warnings

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Credits

This mod and worldgen work is by Papercraft Games. If you build on this, please give credit and share improvements with the community.