Modding Final Fantasy III & IV (3D) with OpenFF

Short tutorials with pictures. Each one takes a few minutes and ends with something you can play.

The Crystal Shrine, a map made in Crystal, running in the OpenFF client

The Crystal Shrine - a map, its models, a cutscene and two weapons, all made in Crystal. Not a line of code.

Download the latest release The project on GitHub Windows 10/11 · needs the Steam copy of FF3 or FF4 (3D) · nothing to install, unzip and run

Two programs

OpenFF plays the games. It reads your Steam copy of Final Fantasy III or IV and runs it with a modern client: any window size, game pads, and a mods folder that can add new maps, items, monsters, cutscenes and C# code.

Crystal is the editor. It opens the game's files - maps, models, text, tables, sound - and lets you change them or add your own. Everything you make is a project; Run in OpenFF plays it.

Pick a tutorial

Getting startedInstall, open Crystal, open a sample project, play it. 5 minutes. The map editorSelect, move, add an object, give it a behaviour: a talking villager, a chest. A map of your ownA new map from a ground model, exits to and from the game's maps, music. Items and weaponsA new item from an existing one; a sword drawn from your own glTF, fitted in the hand. CutscenesCamera moves, lines, a fox that runs over: the timeline. Models, sounds, fontsBring a Blender export, an Ogg tune, a TrueType font into the game. C# codeWhen a behaviour is not enough: a script that hot-reloads while the game runs. Steam modsEdits that install into the Steam game itself - texts, textures, tables. ReferenceEvery component and its fields, every timeline clip, the files, the settings.

The game's own files, in the editor

Most of Crystal is about the game as shipped: its maps with their characters and exits in 3D, every line of text in every language, the tables behind items and monsters, the models with their animations, textures, menus, sound. Open, change, save - into your project, never into the game.

Ur, the game's first town, open in the map editor with a villager selected — Ur in 3D: its 36 characters, the exits, and a villager's script and lines in the inspector.

The text editor on the game's message file — The text: every message, editable, in the game's languages.

A monster model playing its battle animation in the model viewer — A monster with its battle motions - and Export .glb for Blender.

The item table in the table editor — The tables: items, monsters, jobs, shops - the numbers, as a grid.

What a mod can add

A glTF sword and shield in the hero's hands in battle — Weapons and shields of your own, from a glTF, in battle.

A cutscene made on the timeline: a camera shot and a line — Cutscenes laid out on a timeline: camera, lines, effects.

Crystal with the map editor and the timeline dock open — Crystal: the 3D view, the hierarchy, the inspector and the timeline.

The model viewer showing a sword in a character's hand, mid animation — Fit a weapon to the hand while the battle animation plays.

Where things are. This guide is Guide\index.html in the release folder, Help ▸ Guide in Crystal, and online at zerratar.github.io/openff. The longer written manual is Modding.md; the C# API is Help ▸ OpenFF API reference in Crystal, or API.md. What changed in each version: Releases.md.