This is considered a non-issue as only the channel assigned to lightmap index are wiped. If you want to maintain hand tailored UVs generate lightmap UVs to use as a throw away channel.
The merge actor tool no longer saves additional UVs used for the merged mesh. This was not the case in 4.13, but in 4.14 and later this information is no longer present.
Also worth noting is that if the MergeActor Tool left Generate Lightmap UVs on in 4.13 it would set the lightmap as UV2 and still not wipe the second UV from the mesh with the multiple UVs. In later versions it would still wipe the 2nd UV from the model.
Working: 4.13.2 Binary CL-3172292
Broken: 4.14.3 Binary CL-3249277
Broken: 4.15 Automated Build CL-3269047
Broken: 4.16 Dev-Main CL-3273433
1. Open UE4
2. Import the attached Static Mesh with 2 UVs
3. Add the SM to the scene and add a copy or another separate mesh (one from the modes panel works as well)
4. Go to Windows > Developer Tools > Merge Actors Tool
5. Select the two or more actors in the scene
6. In the Merge Actors Tool disable "Generate Lightmap UV"
7. Click Merge Actors
8. Open the Generated Merged Actor and look at the UV's dropdown
Results: Second UV is no longer kept with the merged actors. Only the first.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-41161 in the post.
| 3 |
| Component | UE - World Creation - Worldbuilding Tools - HLOD |
|---|---|
| Affects Versions | 4.14, 4.15, 4.16 |
| Created | Jan 26, 2017 |
|---|---|
| Resolved | Mar 10, 2017 |
| Updated | Jul 14, 2021 |