Unity 2 Cocos

Export 3D scene and assets in Unity to Cocos Creator.

Demo

Unity URP sample scene converted for Cocos and built on the web.

https://amagamina.jp/unity-2-cocos-demo/

Feature

From Unity's left-hand scene to Cocos' right-hand scene.
Image, FBX meshes copy and auto-generate meta files.
Support URP material to Cocos material convert. ( If you are using Built-In pipeline, you can convert to URP with the Unity's support. )
Map Unity's assets to Cocos' assets. (ex. Unity's Cube mesh -> Cocos' Box mesh)

Under development

Support 3D physics feature. (Collider / Rigidbody etc)

⚠️ Caution ⚠️

This is an experimental project. Complete conversion is not possible.
Make a backup of your project if you use it.

The following will not be supported. We need your help!

Prefab support. (Very complicated...)
ParticleSystem / 2D Feature / uGUI convert.
Audio / Animation export.

If you are new to CocosCreator, please read this page first to understand the differences between Unity and CocosCreator. https://docs.cocos.com/creator/manual/en/guide/unity/

Required

>= Unity 2022.3.11f1 ( >= URP 14.0.9 )

>= Cocos Creator 3.8.1

Install

To install via upm, specify https://github.com/ina-amagami/Cocos2Unity.git?path=Packages/Unity2Cocos.

{
  "dependencies": {
    "jp.amagamina.unity-2-cocos": "https://github.com/ina-amagami/Unity2Cocos.git?path=Packages/Unity2Cocos",
  }
}

Or copy /Packages/Unity2Cocos/ into your project.

Use the com.unity.nuget.newtonsoft-json >= 3.0.2

How to

1. Setup

Create a CocosCreator project.
If using PostProcessVolume or FXAA, set up a custom Cocos rendering pipeline. please see https://docs.cocos.com/creator/manual/en/render-pipeline/post-process/
Create a setting file in Assets/Create menu select of Unity2Cocos/ExportSetting in Unity.

2. Configulation

Add the scene you want to convert to "Scenes" list.
Change settings as needed (see below "Setting").

3. Export

Click "Convert for Cocos".
Select export directory (root directory of Cocos project).

4. Run Python script

FBX mesh uuid that cannot be identified on Unity is modified by Python scripts after importing into Cocos.

Run the Python script Packages/Unity2Cocos/Tools/replace_mesh_id.py.

% python3 ./Packages/Unity2Cocos/Tools/replace_mesh_id.py

Enter the folder path: [Your export directory]

If you see the following, you have succeeded. Open the scene in Cocos and check it.

...

- Replace: 929e9c50-5f7a-41ae-93db-7aedb8c94ac4@mesh-name:safety_hat_low.mesh -> 3d871
- Replace: b332724b-ff23-422d-9369-99df2ab5a6ac@mesh-name:level_low.mesh -> 78d63
- Replace: d05f7138-939f-4ab0-a06b-1b7e76e0c6c3@mesh-name:safety_goggles_low.mesh -> c40d4

--- Replace mesh id end ---

Setting

Title	Description
Asset Mappers	If assets are already prepared on the Cocos side, only references can be set automatically. Create a new file in `Assets/Create` menu select of `Unity2Cocos/AssetMapper`. Maps the specified asset to a Cocos asset, specified by Cocos UUID. In Cocos, you can right-click on an asset and copy its UUID.
Script Mappers	Can be created in the `Unity2Cocos/ScriptMapper` menu. Similar to AssetMapper, it maps custom MonoBehaviour C# scripts used in the scene to TypeScripts already created on the Cocos side. Note the use of "Compressed UUID" here. when you copy a UUID in Cocos, you will see the following in the Console. `UUID has been copied: aaf9f561-03d5-4451-967c-0a0feb4c838c , Compressed UUID: aa+fVhA9VEUZZ8Cg/rTIOM` In the sample project, the camera control script is replaced with one created on the Cocos side. * Property conversions are not supported.
Export Web Like Paths	ex) SampleScene → sample-scene
URP Asset	If not specified, the currently used Asset is adopted.
Use Cocos Ambient Light Info	Ambient light of Unity and Cocos is very different, turn ON if you want to use the Cocos defaults.
Mesh Id Match Method	Since Unity cannot know the UUID assigned to the FBXMesh on the Cocos side, we set up a Python script to search for the UUID when modifying the FBXMesh. Mesh Name - Search by mesh name. Triangles - Search by polygon count. Choose the one that works best for your project. Note that neither is perfect, so you may need to set up references manually.
Advanced/	(Details omitted.)

Support Status

Scene Information

Title	Status	Remarks
Ambient Light	✅	Only gradient settings are taken over (because Cocos only supports gradients).
Shadows	✅	Refer to URP pipeline settings.
Skybox	❌
Prefab	❌	Unpack to a normal GameObject and then convert.

Assets

Title	Status	Remarks
Scene	✅	Unsupported components will be skipped.
Prefab	❌
FBX Model	✅
Single Mesh and non-FBX formats	❌
2D Texture	✅	Some formats may not be supported by Cocos.
3D Texture TextureArray	❌
Sprite	❌
Material	✅	If no MaterialConverter is defined, Cocos' Standard shaders are used.
Shader	❌	Use the one prepared on the Cocos side.
Terrain	❌

Components

Title	Status	Remarks
Transform	✅	Converted from left hand coordinate system to right hand coordinate system.
Mesh Filter & MeshRenderer	✅
Skinned Mesh Renderer	❌
Sprite Renderer	❌
Terrain	❌
Camera	✅	Physical parameters are not supported.
Light	✅	Area light not yet supported (will be in the future).
LightProbeGroup	✅
LODGroup	✅
ReflectionProbe	✅	Note that resolution settings are very different between Unity and Cocos.
Volume (PostProcessing)	✅	Global Volume only, uses Cocos PostProcess. Needs to be configured on Cocos side. https://docs.cocos.com/creator/manual/en/render-pipeline/post-process/ Supported only by Bloom, FXAA.
Colliders	❌	Future support.
Rigidbody	❌	Future support.
Particle System	❌
Animator	❌

Material Converters

Unity Shader	Cocos Effect
Universal Render Pipeline/Unlit	builtin-unlit
Universal Render Pipeline/Simple Lit	builtin-standard
Universal Render Pipeline/Lit	builtin-standard
Other	builtin-standard

* If SimpleLit's SpecularMap and Lit's MetallicMap are used, these parameters regenerate the texture since the channels used on the Cocos side are different.

Package License

This software is released under the MIT License. https://opensource.org/licenses/mit-license.php

The UniversalRenderPipeline sample scenes included in the repository were created by Unity Software Inc.