fbx from blender renders inside out

Development Asset Creation
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1

I have an asset that renders very strange when I upload it to UE5. I created the asset in blender, it is an extremely simple 2 piece object. There are no errors when I upload it to UE5 and I am unsure where the issue is.

I am using UE5.3.2 and Blender 4.0.

This is what it is supposed to look like. ( view from blender)

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after importing it into UE5, the axe head turns into this warped mesh. The handle is fine.
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Heres the settings i used to import to UE5 (I believe it is the default)

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Here are the settings i used when using blender to export as a .fbx file. I select both the handle and the axe head before exporting. I used these settings for another 2 piece mesh that had no issues, so I think its on the UE5 side.

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Has anyone seen this issue before? I have spent about 3 days trying to crack it. I would post the .fbx file but the forum is not letting me as I am new.

2

Maybe when you import select “import normals and tangents” instead of just “import normals”

3

Thanks for the reply, unfortunately that did not work.

4

I think its rendering the axehead inside out, you can only see the faces of the mesh that are on the inside, while the ones on the outside are seethrough.

5

I have solved my own issue and am posting the solution here.

The mesh for the axe head has a negative scale value that cause it to be turned inside out. Apparently in blender I could not see the difference because it rendered both sides of the mesh. The z scale of the axe head was -.071, which renders exactly the same as +.071 inside of blender but behaves differently in UE5.

6

In blender you can check the face orientation, and use Alt+N to flip the normal.

7

Ah yes, always apply the scale and rotation inside Blender first.