Hey, so I made some simple union cylinders. I put some negated parts in those parts to create shapes in the cylinder, and it worked as expected when I unioned the selection.
However, when I rejoined Studio, all my unions are gone. If I try separating, nothing’s there. They just, literally get deleted.
Is there a reason for this? Or is it, yet again, an engine bug?
Thanks
Alright it’s confirmed, 99% this is a critical engine bug. Every time I publish my unions get deleted
This happens to me too. Try separating the parts then doing it again. That sometimes works for me. If that doesn’t work I just rebuild the parts that would become the union.
This happened to me while I built my projects, I just decided to build the things out of parts instead or usually I would just make the union thing again, like start over. Basically deleted the glitched original and replace it with another union?
This has been an ongoing problem on Roblox for quite some time now. Hopefully it gets fixed in the near future.
Apparently some one already posted an engine bug report, and I’m guessing engineers are looking into it.
Luckily, I found a great workaround for people (like myself) that don’t really have experience with Blender but still need the functionality of utilizing unions to create the desired shapes and such.
Super easy, create the union, then export it as an obj, then upload it in your game as a mesh. I had no issues with this method. Hope it helps 
In your Studio settings under Physics, at the bottom of the list is a checkbox that says ‘Disable CSGv2’ which basically means that you have the ‘Constructive Solid Geometry version 2’ disabled and you are using the original version which had some glitches. One of these was the disappearing Union trick.
If you already have it unchecked then it might be a newer issue.