Unity Workflow Decision
Unity File Locking vs Smart Merge: When to Lock or Merge
Lock Unity assets when parallel edits cannot be combined reliably or when coordination is cheaper than conflict resolution. Use Smart Merge for text-serialized scenes and prefabs when edits are separable, contributors need parallel work, and the team can review and validate the result.
Lock or merge decision matrix
| Asset/work | Default | Why |
|---|---|---|
| PSD, 3D source, audio, video | Lock | Binary authoring formats rarely have a useful merge. |
| Small text prefab | Merge + review | Separate object/property edits can be combined and inspected. |
| Large shared scene restructure | Temporary lock or single owner | Hierarchy overlap creates expensive intent conflicts. |
| Independent additive scene | Merge/review separate files | Ownership boundary already reduces overlap. |
| Material or ScriptableObject data | Merge + semantic review | Text properties and references remain inspectable. |
| Baked/generated data | Regenerate or lock | Manual combination is often meaningless. |
When file locking is the better tool
- The asset is binary or the authoring tool has no deterministic merge.
- Two edits would affect the same high-level layout, bake, or imported source.
- The merge takes longer and carries more risk than waiting for one owner.
- The team has reliable lock discovery, ownership, and stale-lock handling.
- The edit window is short and clearly communicated.
UVCS Smart Locks, Perforce exclusive checkout, and Git LFS locking can enforce different versions of this policy. The operational details differ, but the decision should begin with asset behavior.
When Smart Merge is the better tool
- The Unity asset is saved with Force Text serialization.
- Contributors edit different objects, components, properties, or prefab instances.
- Parallel work has meaningful business value.
- The team keeps branches short and reviews asset changes before merge.
- Unsafe cases can remain unresolved instead of being silently guessed.
UnityYAMLMerge is the built-in baseline for scenes and prefabs. It can combine many non-overlapping edits, but it should not be treated as proof that the resulting scene or prefab matches team intent.
Add a review layer after automatic merge
MergeSight transparent Smart Merge review can expose Base / Ours / Theirs decisions, conflict classifications, hierarchy, prefab overrides, GUIDs, fileIDs, and references, then preview and validate the proposed result. This fills the gap between a black-box automatic command and an asset the team can confidently accept.
Use a hybrid policy
Most production Unity teams need both approaches:
- Always lock large non-mergeable binary source assets.
- Keep ordinary text scenes, prefabs, materials, and data assets reviewable.
- Temporarily lock high-risk monolithic scenes during known overlap windows.
- Use semantic diff before merge and 3-way context during conflicts.
- Validate merged assets in Unity and CI.
Questions for the team policy
- What is the cost of waiting for a lock versus resolving a conflict?
- Can the asset be split into additive scenes or prefabs?
- Does the merge tool preserve and expose Unity structure?
- Who reviews hierarchy, reference, and override changes?
- How are stale locks and abandoned branches handled?
- What automated checks block an unsafe result?
FAQ
Should Unity scenes be locked or merged?
Use merge and review for text-serialized scenes with separable edits. Use temporary locks for monolithic or high-overlap scene work where conflict cost is predictably greater than coordination.
What is Unity Smart Merge?
Smart Merge uses UnityYAMLMerge to combine text-serialized scene and prefab files with Unity-aware rules instead of relying only on ordinary line merge.
Can file locking eliminate all Unity conflicts?
No. Locks reduce parallel edits for selected paths, but conflicts can still occur through stale branches, related files, reference changes, or edits made before a lock is acquired.
Can MergeSight replace file locking?
No. MergeSight helps review and resolve supported text-serialized assets after changes exist. Locking prevents selected parallel edits. Teams often use both.
Summary
Lock non-mergeable work
Binary assets and high-overlap edit windows benefit from exclusive ownership.
Merge separable text edits
Force Text, short branches, semantic review, and validation preserve parallel work.
Adopt a hybrid policy
Choose per asset and task instead of enforcing one rule across the complete project.
The correct choice minimizes total team cost: blocked work, lost parallelism, review time, conflict risk, and recovery effort.
Next step
Apply this policy to a shared level with the same-scene collaboration workflow.