Trying to look into what’s going on here, I loaded the model and tried to ungroup the “union” part of it, and I got an error pop-up telling that the child data for the union part is not available.
CSGv2 won’t currently operate on anything that doesn’t have child data (it needs the CSG tree telling how the object got made). It is concerning that you got no error message though. Are you using CSGv2, or do you have it disabled, or could you provide the model with child data in place?
I know the feeling all too well and I decided to completely scrap CSG. A year later and I still get corrupt unions and I’m not a person to really take a risk having nearly 70% of my unions corrupt destorys your soul.
Could you elaborate a little on the circumstances when the corruption takes place? Is the model always very complex at that point, or does it sometimes happen with simpler cases? Does it take a long time to compute before it spits out the corrupted result?
A saved file from before the corruption would be helpful, for example an .rbxl file with an earlier version and a short description on what you tried to union with what.
Our current difficulty in even beginning to address this issue is that we have not been able to reproduce the problem.
Really sorry I can’t provide any repos right now but I do appreciate your input and response, I’ll try to install myself into some new faith in CSG and see how it goes. I’ll be sure to ping you in DM if I come across anything now we know someone is aware and listening - it is a help.
I had autosaving off for quite a while and my unions seemingly stopped becoming corrupt. Auto save was re-enabled today and this has been my first corrupt union since I turned auto save off, that I know of anyway.
3 days later and I still haven’t had a corrupt union.
This is most definitely due to corrupted (and probably missing) ChildData. I (believe) by injecting custom child data you can fix this assuming the MeshData of the Union is properly saved however I’m not 100% sure on this (I’ve only recently begun experimenting with this). I can definitely help you get started with this though.
I’ve had similar problems spiking recently. Simple 5-part unions corrupt seemingly more than complex ones. the CSG system should really be fixed, even negative parts can be corrupted the second they are negated
I am saying this on behalf of all Roblox builders that are not working on any external software, please FIX YOUR UNIONS! it’s not fun to see your work spontaneously disappear. This happening really ruined my mood for today and made me question whether i should quit my project or not, or even quit developing on roblox whatsoever. On many instances you have proved that you are not listening to any input from developers.