Getting started
NOTE: Before starting it is highly recommended to create a copy of the game files, primarily the .ipk files, in case something goes wrong. Alternatively you can verify the game files through Steam/Ubisoft Connect to undo any changes.
For pretty much any mod you'll be wanting to modify the game's files. Since they're packed inside of the .ipk archives you'll have to use the Rayman Control Panel to modify them.
You'll find this by pressing the "Open" button for the Archive Explorer.
Then you can navigate to the files you want to modify and right-click to export/import them. If it's a texture then you can export it to a .png file which can then be edited in any image editor program and then imported back into the game! Just make to not press the "Replace" button when importing as that won't convert the file and will thus make the file unreadable by the game!
ubi-canvas level viewer/editor
To start with you'll need to install Unity. Check the ubi-canvas repository to see which is the currently supported version of Unity to use! After that you'll need to either download the repository as a zip or clone it with a git client (such as GitHub Desktop) and add it to Unity. Then you can open the ubi-canvas project.
Here's a tutorial on how to use ubi-canvas:
GameBanana mods
The easiest way to distribute your mods is through GameBanana. That'll also make them directly downloadable in Rayman Control Panel through the mod loader.
In order to create a mod you'll want to use the mod creator in Rayman Control Panel. Check the box for the "FILES" module, press the create button and save it in a new empty folder.
To start with you'll want to add the files. Let's say you want to replace the logo texture in Rayman Legends. That is located in the Bundle_PC.ipk archive file at cache/itf_cooked/pc/enginedata/defaultloadingscreen/logoraymanlegends/animation/logoraymanlegend_pack_basic_001_0.tga.ckd. What you will need to do is to create these same folders in your mod, as well as one for the .ipk that it's in. You do this under the folder added_files which is in the files folder. So the final path will be files/added_files/Bundle_PC.ipk/cache/itf_cooked/pc/enginedata/defaultloadingscreen/logoraymanlegends/animation/logoraymanlegend_pack_basic_001_0.tga.ckd. In here you now want to place your modified logoraymanlegend_pack_basic_001_0.tga.ckd file. Now make sure this is a .tga.ckd file and not a .png file! So you will need to import your .png into the game using the Archive Explorer and then exporting that as a .tga.ckd file so you can use it in your mod.
Note that for Rayman Origins the .ipk file is under GameData/bundle_PC.ipk meaning that the path will have to start with files/added_files/GameData/bundle_PC.ipk.
Once you've added the files then you'll have to edit the metadata.jsonc file. This is easiest to do with a text editor that has JSON support, such as Notepad++ or VS Code, but can also just be done with Notepad. There are a lot of fields to edit, but all you really need to change is the name, description and author. The rest already have default values that will work.
Before finishing you can also optionally add a thumbnail for your mod. This is done my simply placing a file into the folder named thumbnail.png. The recommended image size is 128x128.
Now you're done! All that remains is to zip the mod folder (make sure to zip the contents of the folder and not the folder itself!) and then upload it to GameBanana. Although it is highly recommended to test it first by installing it as a local mod in Rayman Control Panel.
For more details on how mods work in Rayman Control Panel, check the documentation.
