Problems with exporting fbx scene to UDK (4.7.2)

“degenerate tangent which will result in incorrect shading” is the issue that pops up every time i export a FBX scene with “FBX to UE4 Batch Exporter v1.1” script and i mapped every object with 100x100x100 UVW map & reset the pivot points to x=0 Y=0 z=0 coordinates in 3DSMAX. But what happens is that the scene i was exporting is quite a simple model of a apartment with just walls to test the importing&exporting process, the result was that some objects were imported and some didn’t import, the message that pops up is the message “degenerate tangent which will result in incorrect shading” on the object that couldn’t be imported.

Hello Mayweather,

Thank you for your post. I am looking into replicating your issue and so far I have not been successful using models made internally here at epic. Would you consider uploading your 3dsMax scene so that I can attempt to reproduce the issue?


Good morning Ben,

I’m having difficulties uploading the 3DSMAX file here through attachment, is there a way i could email you the file if its convenient for you.

Warm regards,
~ Lee.

Hello Mayweather,

I am sorry that you are having issues with uploading. If you look in the forums for me ( ) you can private message me with a link to a dropbox (or the cloud storage of your choice). I can then download the file and take a look!


Hi Mayweather,

Currently this issue with Degenerate Tangents is being investigated by the engineers and has been reported with Ticket UE-11426.

I’ve added your post to the report so that I can update once the ticket has been updated by an engineer.

Thank you!


Evening tim,

I figured it out, with the correct importing workflow thanks for the prompt input!!

FIXED it with the correct importing workflow thanks for the prompt reply ben!

With regards to Degenerate Tangents, 4.8 will have an option to disable MikkTSpace in the Static Mesh Build settings. This is fixed with CL-2519373.