What is error "CSG returned error code -15", and how do I fix it?

[al_an172 (PelonPello)]

I have looked all over the web to see if anyone else had the same problem but nothing.

[TheRobloxianDerg (ヘイデン)]

Hi there. Im a builder. Can you read this and see if it has any correlation?

CSG Returns Error Code -15 For No Reason With Small Parts

So I’m currently working on an elevator installation project for my test tower game. Yesterday was all fine and dandy, and I hop off and go to bed. I come back on this morning, boot up my PC as usual, and open Studio. Installs an update, nothing unusual. I open my place, and I resume work. I get to work on a beveled panel using Unions, and I try and separate it. Nothing happens except that my union gets deselected. Okay… odd. I try again. Union deselects again. I try once more. Same thing! …

[al_an172 (PelonPello)]

Thinking of it, studio did get a update yesterday, so yeah everything checks out, but why is it happening a year later?

[astrovue]

Sometimes ROBLOXs’ CSG engine can fail to calculate some geometry. When I encountered this problem, I re-opened Studio and it stopped producing the error.

If you don’t want this happening again then I would switch to a secondary 3D modeling software such as Blender, and make your assets from there which you can import into Studio.