Generate Lightmap UVs for Editor Combined Mesh

Hi,

I have combined meshes in the editor, and the plugin itself did not regenerate lightmap uvs like I could if I just imported the mesh. How can I generate the lightmap UVs in this case?

 

Hey! Did you find solution? I have the same problem

 

Hey @keninger, @Rotecks,

There's a few ways to get the UVs, e.g.:

• Use

  Unwrapping.GenerateSecondaryUVSet

• Use

  StaticBatchingUtility.Combine

  instead of the plugin you mentioned to combine your meshes (that seemed to have light mapping UVs in the first place)
• Adjust the original code to preserve the UVs

 

Thank you! It works!
But sometimes for some meshes I get such error :

UnityException: You can generate UVs only for meshes with vertices inited.
UnityEditor.Unwrapping.GeneratePerTriangleUVImpl (UnityEngine.Mesh src, UnwrapParam settings)
UnityEditor.Unwrapping.GeneratePerTriangleUV (UnityEngine.Mesh src, UnwrapParam settings) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Unwrapping.bindings.cs:43)
UnityEditor.Unwrapping.GeneratePerTriangleUV (UnityEngine.Mesh src) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Unwrapping.bindings.cs:37)
UnityEditor.Unwrapping.GenerateSecondaryUVSet (UnityEngine.Mesh src) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Unwrapping.bindings.cs:52)
StairRailing_Corrector.meshBacker () (at Assets/Units/Rooms/Part_2/Bridge/Scripts/StairRailing_Corrector.cs:330)
StairRailing_Corrector.UpdateColliders_And_Mesh () (at Assets/Units/Rooms/Part_2/Bridge/Scripts/StairRailing_Corrector.cs:188)
Bridge_Corrector_Abstract.SaveMeshAsAsset () (at Assets/Units/Rooms/Part_2/Bridge/Scripts/Abstract/Bridge_Corrector_Abstract.cs:73)
Bridge_Corrector_Abstract_Editor.DrawButtons () (at Assets/Units/Rooms/Part_2/Bridge/Editor/Scripts/Abstract/Bridge_Corrector_Abstract_Editor.cs:12)
StairRailing_Corrector_GUI_Editor.OnInspectorGUI () (at Assets/Units/Rooms/Part_2/Bridge/Editor/Scripts/StairRailing_Corrector_GUI_Editor.cs:29)
UnityEditor.InspectorWindow.DoOnInspectorGUI (Boolean rebuildOptimizedGUIBlock, UnityEditor.Editor editor, Boolean wasVisible, UnityEngine.Rect& contentRect) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1625)
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)

Do you know the reason???

 

This error is thrown when there are no vertices in the mesh (vertex count is 0). Apart from the mesh simply not having that data, one other reason could be that you called

Mesh.UploadMeshData

and passed

true

into the

markNoLongerReadable

parameter, which will deallocate the CPU-side data.

 

I'm doing this and it works...but every single UV island is miniscule, about 1 pixel across in the lightmap.
It's a lowpoly VR game so I am manually combining entire scenes into single figure drawcalls. I suspect this issue is because the resulting combined mesh has a massive bounds compared to any individual UV island? The scene lightmaps fine if I don't generate combined meshes, but I can't copy those UVs unless I can guarantee all the meshes that get combined are using the same lightmap page.