# FBX Import Level node rotation bug under rare circumstances

**URL:** <https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412>\
**Category:** World Creation\
**Tags:** unreal-engine, FBX, import, level, bug-report, UE4, question\
**Created:** [August 7, 2016, 7:14pm UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412 "2016-08-07T19:14:20Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ldcue](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ldcue](https://forums.unrealengine.com/u/ldcue)\
**Post date:** [August 7, 2016, 7:14pm UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412/1 "2016-08-07T19:14:20Z")

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Hello,

When importing a fbx map will lights and some nodes that doesn’t have attribute, I found out that a node that doesn’t have an attribute, gets rotated around 90° yaw if the node before it was a light.

I had to debug the engine and found out that the potential issue is in the file “Engine\Source\Editor\UnrealEd\Private\Fbx\FbxMainImport.cpp” in functionFFbxImporter::TraverseHierarchyNodeRecursively. The issue is that ChildInfo.AttributeUniqueId is not initialized, causing it to get a value that was previously on the stack if the node doesn’t have an attribute. For UE developers, the fix is to simply add ChildInfo.AttributeUniqueId = ChildInfo.UniqueId when the node doesn’t have an attribute.

I have checked and the bug is still present on UE 4.13 preview.

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**Author:** ![Tim\_Hobson](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tim\_Hobson](https://forums.unrealengine.com/u/Tim_Hobson)\
**Post date:** [August 8, 2016, 12:52pm UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412/2 "2016-08-08T12:52:08Z")

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Can you please provide detailed repro steps from your modeling program to UE4?

Also, is this any mesh or only Skeletal/Static that are affected?  
Does modeling program matter, or have you tested with multiple programs, or FBX versions (ie. 2013, 2014/2015, 2016)?

Thank you!

Tim

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**Author:** ![ldcue](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ldcue](https://forums.unrealengine.com/u/ldcue)\
**Post date:** [August 9, 2016, 12:17am UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412/3 "2016-08-09T00:17:53Z")

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Unfortunately, I generate FBX files through C++ code, I haven’t found a way to reproduce this bug in 3ds max, I use FBX2016, so this affects other versions aswell. You can reproduce this through code by creating a light node and another node without setting to this one an attribute, adding the light first then the other node to the scene.

I have attached a FBX that reproduces this bug by using the Import Level feature in UE. The scene consists of one light, 2 nodes without an attribute and a node with a FbxNull attribute that is used avoid this bug.

When asking the question I didn’t know about FbxNull, as it solved my issue since. However, people may encounter this rare bug if they use custom tools.

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**Author:** ![Tim\_Hobson](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tim\_Hobson](https://forums.unrealengine.com/u/Tim_Hobson)\
**Post date:** [August 9, 2016, 2:17pm UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412/4 "2016-08-09T14:17:49Z")

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Thanks for the clarification. I’ve added a ticket for this issue.

You can track the status here: [Unreal Engine Issues and Bug Tracker (UE-34410)](https://issues.unrealengine.com/issue/UE-34410)

Thank you!

Tim

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**Author:** ![Kakushi\_52](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Kakushi\_52](https://forums.unrealengine.com/u/Kakushi_52)\
**Post date:** [February 12, 2019, 5:33am UTC](https://forums.unrealengine.com/t/fbx-import-level-node-rotation-bug-under-rare-circumstances/366412/5 "2019-02-12T05:33:27Z")

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Has this been fixed? With UE 4.21, whenever I try to import any FBX by “Import Into Level” with an option “Individual level Actors”, all actors imported have been rotated 90 degrees in X.