When Making Union: CSG returned error code -11/-14

[InfinityBlot (Blot)]

When creating a Union between multiple parts, I got a message stating that the Union failed, and to file a bug report:

First Occurred: 1/20/2024
Last Occurred: 1/20/2024

Crash Dump

Reproduction Steps:

1. Download Place File (in Crash Dump)
2. Open Place File in Studio,
3. Create a Union of all Unions and Parts in the Workspace.
4. Roblox Studio either returns error code -11, error code -14, or remains unresponsive while using around 20-30% CPU and 2000 MB memory.

[thirdtakeonit]

Thanks for the report! We’ll investigate and follow up with updates.

[mrrblato]

Hi,
would you be able to DM the (Crash Dump) place file to me. For some reason I can not seem to download it by clicking at the link.
Thank you!

[InfinityBlot (Blot)]

Sure! I will send it right now.

[mrrblato]

Hi,
so I’ve tried out making a union of all the “Union” parts in the workspace you sent.
I get -14 error. This error indicates that the triangle limit for the mesh resulting from the union is exceeded (I know, “error code -14” is not really a helpful error message - we are currently working on having more meaningful error messages reported for CSG in Studio).

The reason you see this error code is that a mesh of a Part in Roblox can not exceed 20K triangles. This error (-14) indicates that after performing the union, the system was not able to simplify the resulting triangle mesh to under 20K triangles.

I suspect this is due to texturing of windows and walls - since texture seams effectively prevent triangles from getting merged together.

My advice is that as a workaround, you union these parts into a few separate Union parts rather into one large union.

As for -11 error, I haven’t managed to reproduce it yet, but I will keep experimenting with unioning different parts in your place, and report back.

Cheers!