# studio-undeclared-group

> An object uses a collision group the scene does not declare.

| | |
| --- | --- |
| Kind | Studio problem |
| Reported by | Studio validation: the Problems panel, Play, Publish and the MCP `validate` tool |
| Code in the Studio | `undeclared-group` |

This is a warning. Scenes list their collision groups; an undeclared group still works, but the scene's group list and pickers will not show it.

## Fix

- Add the group to the scene's groups, or pick a declared one.

## See also

- [Problems and validation](/studio/playtesting)