Lighting build failed. Swarm failed to kick off

Development Rendering
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21

Btw, should I delete the file or rename it? I renamed instead of deleting

22

I just through all the meshes in my project and gave each one of them a unique name.

Still the same error.

Also I found some duplicate meshes. I tried deleting them but it wouldn’t let me. Maybe I need to delete these duplicate meshes instead of renaming them?

23

Ok so I went through every single one of my meshes (felt like the most pointless ever done lol).

And I still get the same error.

What is happening?

24

for what you copy this same meshes meany times, or make this same names, its not prof. ???, first of all, we told you, what you must do to fix this, its simple, go to work, and clean this mess, its very imprtant to create all project without technical bugs, errors, 400 meshes its a like “Notihng to do” :))), i worked witch one project, where i found more than 10.000 wrong names, now its ok.

25

Hey, sorry I did not realize you responded. I corrected all the names of the meshes so each of them have different names now. However I am still getting the same error :frowning:

26

I don’t think the problem is duplicate meshes. Because I can build lighting on a different level in the same project with no issue. It’s only on my main level that I get this error.

27

one again time i have this same problem, and i solved by rename duplicate names of mesh and materials

28

I solved that problem by fallowing this post:

maybe it will help good luck !

29

Alternative steps that might work for some people: UE4 Fix – “Lighting build failed. Swarm failed to kick off.” – Zag's Blog

30

[SOLVED]

I found a way to solve it through code. I wrote this little piece of code here:

	TMap<FGuid, UMaterialInterface*> guids;

	for (TObjectIterator<UMaterialInterface> it; it; ++it)
	{
		UMaterialInterface** result = guids.Find(it->GetLightingGuid());

		if (result == nullptr)
		{
			guids.Add(it->GetLightingGuid(), *it);
		}
		else
		{
			it->SetLightingGuid();
			it->Modify();
		}
	}

I personally have an editor plugin to do this but I think it could work anywhere in code.
This actually regenerates the lighting ID that causes the conflict that you see in the swarm agent log.

After that, just save the modified assets and rebuild.

31

littlerussian: this worked perfectly. You saved us. Thank you! Would love if this was an editor plugin.

32

Hello, where do I put this code. Sorry Im just an archviz student not a coder.

33

link text
This is the editor plugin. You need to compile it, because if I upload the binary I exceed the 5.2 MB

34

That’s it! you saved our day :smiley: thank you so much

35

Made an editor plugin from that code above, cheers.

36

thank you!!!

37

works ty!!!

38

Thank you for solving my problem.

39

it worked. thank you very much!!!

40

Bumping to say thanks to OP and the the users below for the solution/plugin.

Really wish they would implement a method to determine which material/mesh or object is being referenced to from the GUID. Just knowing what is causing the issue would have saved hours of frustration, instead of having to go through every single asset in your level.