Unity to Godot, a concept map and a rebuild order that works

The tools sold as a Unity to Godot converter or exporter work on the data side, such as meshes, materials, textures and where objects sit in a scene. That can save days on a large level. What no tool can carry is behaviour. Your MonoBehaviours call UnityEngine APIs that do not exist in Godot, your Animator controllers are a Unity format, and your physics tuning depends on Unity's physics settings. One example is Relative Games' Unity To Godot Exporter, a paid Unity plugin for Unity 2021.3 or newer and Godot 4.4 or later. It exports static meshes, placement, decals, skinned meshes, terrain with trees and details, and materials, converting Shader Graph to visual shaders. By its own description it does not touch code and leaves cloth, particle emitters, fully custom shaders, ECS components and animations behind.

So plan the move as two jobs. Moving content is mostly file work and import settings. Rebuilding behaviour is programming, and it is where the time goes. Treat any tool as help with the first job, never as a replacement for the second.

The table above covers the everyday mappings. Two of them change how you design. The first is nodes. In Unity you add components to a GameObject. In Godot you build a small tree of nodes, where a CharacterBody3D has a CollisionShape3D and a MeshInstance3D as children, and the script sits on the root. A Godot scene is both a level and a prefab, so the reusable enemy you built as a prefab becomes an enemy scene you instance.

The second is signals and await. Signals are Godot's observer pattern, messages a node emits when something happens that other nodes connect to. Where you wrote a coroutine with yield, you write await, for example `await get_tree().create_timer(0.5).timeout`, and any function that uses await becomes a coroutine itself. ScriptableObjects map to custom Resources, which serialize automatically and show up in the Inspector.

C# works in Godot 4 through the .NET build of the editor. Godot's own documentation states that C# projects cannot currently be exported to the web, and that Android and iOS support has been available since Godot 4.2 but is experimental. For a desktop game on Steam or itch.io, C# is a solid choice and the shortest path from Unity.

GDScript is the other option. It is what most Godot examples and tutorials use and it needs no separate build step. Many teams keep C# for heavy systems and use GDScript for glue. In Summer, C# is available in the desktop editor, and desktop builds for Windows and macOS are the release path.

A common claim is that Asset Store purchases only work inside Unity. The standard Asset Store EULA does not say that. Section 2.2.1 licenses a non-restricted asset to be incorporated, with substantial original content, into an electronic application as an embedded component that is not a substantial portion of the product. It does not name an engine.

Three cases still need care. Restricted Assets carry their own terms in the materials that come with them, and some packages are governed by a separate provider EULA, so check each one. Code assets, editor extensions and shaders are written for Unity and will not run in Godot whatever the licence says. And section 2.2.1.1(g) prohibits using Asset Store assets to train or feed AI models without the provider's or Unity's consent, so do not use store art as a reference image for a generator.

Rebuild the player controller first, then one representative level, then the core loop, then the UI, then the content. Each step gives you something you can play and compare with the Unity build, which is the only reliable way to know the port feels right.

Copy numbers, not intentions. Open the Unity script next to the Godot one and match every value, then play both builds back to back. Check the physics tick rate in both projects, since Unity's fixed timestep and Godot's 60 physics ticks per second may not match, and check the result by feel as well as by number.

Summer is a desktop engine for macOS and Windows that is compatible with Godot 4 workflows, with an agent built in. Put your old C# in the project folder and ask the agent to rebuild one system at a time with the original as the spec. It writes the scene and the GDScript, runs the game and reports problems, and you compare the result with the Unity build.

There is no automatic Unity importer in Summer, and the agent does not replace your judgment on feel. What it removes is the blank project, so you spend the time correcting and tuning instead of retyping.