Unions are the bridge between users looking to build general 3D assets in Studio, and those who have moved onto a more complex, dedicated 3D modeling program such as Blender. They’re made to be accessible, easy to understand and create. Even those just taking their first steps into Studio should be able to pick up on how to use unions without much trouble. They’re even being used in Roblox’s recent Builder Challenge, to show what Roblox Studio is capable of right out of the box with no external software.
Participate in our first Builder Challenge!
So why is it that for something which is intended to be so accessible, we can’t easily manage our unions? You need to have your union saved somewhere such as a game or a model to be able to easily access it, even though it creates SolidModel asset IDs for your unions upon saving them to Roblox. If your union happens to corrupt during an update to your game, you need to dig out a backup you’ve saved.
How to recover invisible / corrupt unions
The reliable method to dig out an old union you haven’t backed up is somewhat ridiculous. To sum up PeZsmistic’s thread here, you need to save a blank union to a model file, go to one of Roblox’s API pages, and replace the asset ID inside your model, inserting it into Studio and hoping that’s the right one. Over and over and over. And the only reason we have this method is because they dug up the API and wrote a whole guide on how to use it for this specific purpose. Even now, I’d imagine there’s a lot of players who don’t even know this guide exists.
If your asset isn’t something you worked on recently, every option has its own cumbersome downsides. Do you tediously dig through old unions until you find the right one? Do you revert to an old version of the game and grab the original union? Perhaps it’d just be easier to remake the union entirely? For something which so many builders rely upon, it’s silly that we’d have to resort to jumping through all these hoops just to recover an asset, when it should be as simple as scrolling through your work and inserting it like your meshes or images.