[Epic Official] FBX Import Reporting


Thank you for your patience. We are working on a universal fix for these types of import rotation issues. Once we have more done with this, we will let everyone know.


Thanks very much for the update Alex

Reimport of textures that are referenced from FBX doesn’t work right in 4.2.
I build a mesh in 3ds Max, and build a simple material with diffuse, gloss, and bump maps (which really is a normal map.)
I then export as FBX.
I import this FBX into the engine, generating a static mesh, a material, and three texture references.

Then I re-paint one of the textures in Photoshop and re-save (same name,) and select “reimport” in the content browser for this texture.
However, it just says “re-imported texture from FBX file” and shows the old version.
Even if I update the texture in Max, and re-export the FBX, selecting “reimport” on the texture still keeps the old texture image.
I had to rename the texture to some other name, and then create/import a new texture manually, and then remove the renamed texture, replacing references with the new texture, to get the new image in.

Hope this is clear.

Hi jwatt -

It is expected if you import the material and texture from an FBX to have to update the FBX for the texture to be updated. When you import the FBX with materials and textures into the editor, does a [Name of FBX].fbm directory appear in the same locationas your FBX? This is actually where your texture in the editor is sourced from and where you would need to make changes.

Thank You

Eric Ketchum

No, there is no “.fbm” folder. I export the meshes with textures referenced, not included.
Even after the texture looked right in Max, and I re-exported the FBX, and tried to re-import the texture in UE, it had the old data (looked wrong.)
I feels like there may be a bug where the old data is “sticky” in a case like this.

Animated skeletal mesh from Blender 2.70a hangs the import process. It loads well as a static mesh though.

==== EDIT: I’ve got a solution!
Fixes FBX export to UE and to 3DS Max.

The problems is that Blender doesn’t always have a 0.000 influence. No, in fact each vertex has its own set of groups to it which belongs. That means that some vertices can contain NO groups.
The solution: have at least one bone with influence on every vertex in mesh - even 0.005 weight is OK.

I mad at Blender since I bought UE4. Still, Epic devs, please take such scenario into consideration - as it’s the design of Blender and not going to be fixed.


In the log file:

LogWindows:Error: appError called: Assertion failed: InfluenceIndex

[File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.2\Engine\Source\Developer\MeshUtilities\Private\MeshUtilities.cpp] [Line: 2189]

Stack: Address = 0x85d4d866 (filename not found) [in C:\Program Files\Unreal Engine\4.2\Engine\Binaries\Win64\UE4Editor-Core.dll]

Hey there. I also have some Bugs here. Animation works fine in Blender (tested 2.7a and 2.71 with new fbx exporter) . I get weird issues when imported. looks like some motions between frames are missing or something like this. Send me a pm if you cant download from Drive.



Edit: When i duplicate the last frame and extend the animation from 27 to 35 frames (doesnt matter how far) no glitchy walk is there. There’s just a problem with the length of the animation then… this pushes me back to the very beginning… arrgh.

Hi jwatte -
Yes I was able to reproduce this issue, and there is a fix in the works. I do not have an ETA for you just yet

Thanks for your help tracking this down

Eric Ketchum

Hi Oskar -

We are actually in talks with Blender’s developers right now on getting a cleaner import path into the engine. So keep checking the forums and letting us know where your problems are as we move forward.

Thank You

Eric Ketchum

Thank you so much! Looking forward to it.

I have a problem with a simple bed model I made. I made it in blender, and exported it as a FBX file. The model looks like this:


I exported it as a FBX, and imported it in UE4. I didn’t triangulate it before exporting. You saw a lot of triangles on the surface when I played the game. It looked like this:


It, after building the lighting, also went fully black, which I fixed by making the lights movable (I atleast fixed that before going here :slight_smile: ). Is there a fix/reason and/or should I make the model less high-poly?

Is it possible to fix this behaviour with the Blender FBX exporter 7.4, when i import as a rigid mesh, it imports all the objects as seperate objects in UE 4, when i export the same File from 3ds Max and import it as rigid Body, it is only one file… Don’t know whats the problem… Importing it with Bones attached as a rigged skellatel mesh works.

I’m animating a Mechanical Object so the object animation as rigid mesh is better for me.

i would like to give you the files, but i can’t due to licensing…

Kevin Gruber

This is correct, UE4 is a Z-Up World, and it correctly ‘fixes’ that bit for us. At the moment though it is not rotating the meshes to be X-Forward as X is the Forward vector in UE4 - they have commented here that they are working on it though.

Whilst agree it’s annoying I am used to Y-Up as I use C4D and have used Unity for years but a LOT of game engines use Z-Up. If you are a Blender or Max user, you would use Z-Up and in Maya you can switch it. Changing Unreal to be able to arbitrarily switch between Z and Y Up I think would be massive massive undertaking. In this case they are doing us a massive favour otherwise we would be modelling everything face down :slight_smile:

I bet Epic Games has heated debates about this issue lol. Actually, I’m not quite sure how FBX works. I know that is does write a Up Axis into the FBX file. I do not want them to change UE4 from Z-up to Y-up(that indeed would be a massive under taking). I just want the engine to respect the Up Axis and orient the data properly instead of flipping Y-up axis in the FBX to a Z-up axis in the editor. I hope that make sense? I think that’s a easy problem to fix compare to figuring what is front from, say Modo/Max/Maya and front in UE4,because FBX doesn’t write out whats front,back,left,right,bottom only whats “top” - the Up Axis?

If the engine stop flipping Y Up Axis to Z up axis, that means we’ll be forced to use Z-up coordinate system in our 3D app,but that’s not a big deal unless you deep into a project already.

edit: After some thought, maybe this Y-Z up isn’t such a big deal? I don’t think it negatively affects the animation data coming in(that’s my biggest concerning was animation)? And I think once Modo can actually Z-up FBX files, I’ can just switch to Z up coordinate system and everything should import properly without any flipping between Z/Y.

Hi RRR3000 -

Can you please attach your FBX so we can test and help you out?

Thank You

Eric Ketchum

Hi, my editor crashed when importing a character skel mesh after updated the editor to version 4.2.1, but it import fine in version 4.1.1. Just wondering if this is a common issue?

Hi Rogzlu -

We have not had this reported, but if you are willing to share your Character’s FBX we will look into it.

Thank You

Eric Ketchum

Hi. I have made several things in 3d Coat but most of them end up having some black areas on them after rebuilding lighting. Any help would be greatly appreciated.
Rock pic
fbx and color and normal

Do you have 2 UV Sets? you need to do your normal UV in 3DCoat then add a 2nd auto unwrap (you need non-overlapping UV’s for the light mapping), then in UE, double click the mesh asset, go to the light mapping details/advanced and set which UV set is to be used for your light maps. (you can use the UV view to preview them)