UE 5.5 FBX Interchange Importer Naming Regression with "Combine Static Meshes"

General Feedback & Requests
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It looks like the new interchange-based FBX importer handles the naming of static meshes that contain collision differently than in the prior FBX import workflow of UE 5.4.

In Unreal 5.4, if I import the FBX file linked at the bottom of this post with “Combine Meshes” turned OFF, I’d get the following static meshes:

  • SM_MasterBedroom_Wall_02_MasterBedroom_Wall_02
  • SM_MasterBedroom_Wall_02_MasterBedroom_Wall_02_Moulding_Base_Right
  • SM_MasterBedroom_Wall_02_MasterBedroom_Wall_02_Moulding_Crown_Right
  • SM_MasterBedroom_Wall_02_MasterBedroom_Wall_02_Window_01_Opening
  • SM_MasterBedroom_Wall_02_MasterBedroom_Wall_02_Window_02_Opening

The same FBX, imported under 5.5 interchange with “Combine Static Meshes” turned OFF, results in the following static meshes:

  • NN36WzSBQ0qP_jIQNtS8-g0_141
  • MasterBedroom_Wall_02_Moulding_Base_Right
  • MasterBedroom_Wall_02_Moulding_Crown_Right
  • MasterBedroom_Wall_02_Window_01_Opening
  • MasterBedroom_Wall_02_Window_02_Opening

The FBX was created by Blender. It looks like when a mesh contains collision meshes nested underneath it in the file, Unreal 5.5 is naming the static mesh after the “mesh” inside the object, rather than using the object name. Here’s how this static mesh looks in Blender before export to FBX, to clarify what I mean:

image
image412×482 52.1 KB

I would expect the name of mesh to be MasterBedroom_Wall_02 rather than NN36WzSBQ0qP_jIQNtS8-g0_141.

Here’s a link to the FBX:

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UPDATE: It doesn’t seem like the naming of that first mesh is influenced by the presence of the collision objects nested under it in the FBX.

I tried with this structure:

image
image477×358 39.5 KB

But the name of the imported static mesh still ended up being NN36WzSBQ0qP_jIQNtS8-g0_141.

Here’s the flattened FBX that still reproduces the issue:

So, I’m not exactly sure what’s causing Unreal to name the first mesh after its geometry rather than its object.

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I reproduced and it does not look normal.
I created a ticket. Thank you for reporting.

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