Today I will be explaining why meshes are superior to unions and how to convert your unions to a mesh.
Why Meshes Are Superior To Unions
1. Unions can corrupt
If you have ever used unions before, then you probably know that they can corrupt randomly, which could potentially ruin hours of hard work. Although there are ways to fix this, it is more reliable to just use meshes instead, which shouldn’t be corruptible, and can easily be reuploaded if a problem arises.
2. Unions can only scale uniformly
When scaling a union, you will be unable to scale it individually on just one axis; it will automatically enlarge or shrink the union to maintain it’s original proportion, which is annoying to me, especially when I want to reuse something but also want to make it have a different proportion. Meshes, on the other hand, can be scaled just like parts and can be stretched without the entire meshes also enlarging or shrinking.
As of June 15, 2022, Roblox has changed union scaling behavior, which allows non-uniform union scaling. You can read about it here.
3. Unions are inefficient
In the 2018 Roblox Developer Conference, it was announced that meshes are indeed better than unions. You can watch about it here.
Here is a helpful post explaining exactly how unions are inefficient. You can read about it here.
Converting Unions To Meshes
1. Export the union
2. Create the mesh
3. Upload the file
Be sure to check out @MissingFeature’s tutorial as well, which involves importing the file to Blender to optimize it. You can read about it here.
You have now converted your union into a mesh. This is incredibly useful, especially if you want to use Roblox’s CSG instead of third-party modelling software, but want to prevent corruption and improve performance.