CustomIslands Mapmaker Kit

Download this MANUALLY (the "Manual Download" button on this page). It is a Unity project, not a runtime mod - a mod manager would install it into the game where it does nothing.

Build your own islands for How to Fish and load them with the CustomIslands Loader mod. Sculpt terrain, dress it with the game's own props, place working shops and NPCs, and ship it as two files anyone can install.

This kit contains zero game assets. It is tools only. Everything from the game - props, materials, islands - is imported from your own installed copy during setup. What you build and publish is your business; the kit stays clean.

What you need

• Windows PC with about 20 GB free disk space (Unity ~8 GB, the ripped game files ~5 GB, working room for the rest)
• How to Fish installed (Steam)
• Everything else is free and covered below

Part 1 - Install Unity (one time)

1. Download Unity Hub from unity.com/download and install it. Create a free Unity account when it asks (choose the free Personal licence).

2. Install the exact editor version the game uses - 6000.4.4f1. Unity Hub does not list it, so use this link (it opens Unity Hub and installs the right version):

   unityhub://6000.4.4f1/360f97ecca93

   Paste it into your browser's address bar if clicking does nothing. No optional modules are needed - untick everything to save space.

3. Wait for the install to finish (several GB).

Part 2 - Open the kit (one time)

1. Unzip this kit anywhere you like, e.g. Documents\HTF Mapmaker Kit.
2. In Unity Hub, Projects tab, click the arrow next to "New project" and choose "Add project from disk" - do NOT create a new project.
3. Select the unzipped folder (the one containing Assets, Packages and ProjectSettings).
4. Open it. The first import takes a few minutes. When it finishes you should see a "How to Fish" menu in Unity's menu bar - that menu is the whole kit.

Part 3 - Set up from your game copy (one time)

1. Download AssetRipper (free) from github.com/AssetRipper/AssetRipper/releases
   • grab AssetRipper_win_x64.zip, and unzip it anywhere.
2. In Unity: How to Fish > Set up from your game copy.
3. Point the window at the AssetRipper exe you just unzipped, check the game folder it found, pick an empty folder to rip into, and press "Open AssetRipper and watch for the rip".
4. AssetRipper opens as a browser tab. In it: File > Open Folder (the game path is already on your clipboard - paste it), wait for the game to load, then Export > Export All Files into your chosen folder, using the blue Export Unity Project button.
5. The kit watches that folder and offers "Import now?" the moment the export finishes. Accept - one progress bar later everything is imported, repaired and armed (the finish dialog shows the counts: terrain stamps, props gathered).

That is the whole setup. From here on it is just mapmaking.

Making a map

1. How to Fish > New map (blank), or New map from any island to start from a real island's terrain.
2. Open How to Fish > Map Creator - sculpt the ground, stamp real island terrain with the Stamp brush.
3. Dress it with How to Fish > Prop brush - the entire prop library from every island. Props placed with a "Place as" choice become real gameplay in game: a (Purchasable) becomes a working shop stand with a price tag, a (Pickup) becomes a real item lying there.
4. The rules the loader depends on:
   • everything under a root object called IslandHolder
   • a PlayerSpawnPoint and a BoatSpawnPoint marker
   • colliders on anything you stand on (Maintenance > Make colliders match their meshes does it)
5. Sanity-check with Maintenance > Check the map.
6. Test it: How to Fish > Build and install into the game, then just start the game.

Your map is two files

yourmap.bundle (built by the kit) and yourmap.json beside it - the kit writes both when you build:

{
  "name": "Coral Cove",
  "author": "you",
  "replacesIsland": 2,
  "casinoFromIsland": -1
}

replacesIsland is part of your map's design, not a preference. Your map stands in for one of the game's five islands (0 to 4) and borrows that island's NPCs, shops and progression - a custom island 2 can only ever replace island 2. Choose it when you start building, declare it here, and the loader enforces it.

Replace, not add. The game's world is exactly five island slots - only one island exists at a time, and travelling swaps which one is loaded. There is no ocean where a sixth island could float, so a custom island always TAKES THE PLACE of one of the five. Adding extra islands is not possible with this kit.

Want an island that borrows nothing? Players can set ImportGameplay = false in the loader's config and your map arrives with no NPCs or shops at all - pure scenery plus whatever you placed.

casinoFromIsland: islands 3 and 4 have casinos - set 3 or 4 to borrow one onto your map (place it with How to Fish > Put a casino here).

Skies are not the map's business: players running Living Skies get the full day-night cycle and storms over every island, yours included.

Sharing your map

Players drop both files into BepInEx/plugins/HTFMaps/. Or publish on Thunderstore: zip them inside a folder named HTFMaps with your icon, README and manifest, and add CustomIslandsLoader as a dependency - mod-manager installs then just work (BetterIslands is the template to copy).

Co-op: everyone in a lobby needs the same maps installed.

If something goes wrong

• The How to Fish > Maintenance menu holds every builder and repair tool individually - setup runs them all automatically, so you only need them for recovery.
• Maintenance > Diagnose the open scene explains most oddities.
• Red errors on first open usually mean the wrong Unity version - it must be exactly 6000.4.4f1.

More from Yoxi

• CustomIslands Loader - the mod that runs custom islands (required for any island pack)
• BetterIslands - an island pack: a hand-built custom first island, more coming
• Living Skies - day-night cycle PLUS storms, rain, lightning and thunder
• HTF Day and Night - the calm-sky day-night cycle on its own

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Kit and loader built by Yoxi.