Importing an FBX from blender with different materials crashes the editor.

This kept happening for me on various models and I figured out why. If there is no material on an object when you export it from blender, but you add one in unreal, the next time you import the model (say, after making some changes in blender) it will crash the editor.

So to duplicate the problem:

  1. Make a model in blender and export an FBX (don’t add a material).
  2. Import it into Unreal.
  3. Open up the model in Unreal and add a material.
  4. Go back to blender, change the model, then export the FBX again.
  5. Click the import button when it appears in Unreal.
  6. Be sad because your editor just crashed.

You can stop the crashing for the time being by adding the same number of material slots in blender as you have in Unreal.

Check this one Ue4 Crashes after FBX REIMPORT - Platform & Builds - Epic Developer Community Forums

That’s a different modelling program, I think.

Hey Kajenx,

Are you in 4.14.2? We have a fix for an issue like this in 4.14.3. See UE-40229

I’m using 4.14.3, so I don’t think that fixed this problem.

BTW, I noticed that in blender objects are automatically assigned a material. The crash was happening for me when I exported objects with no materials assigned at all. I’m not sure if the same thing would happen with more than one material in blender and only one in unreal (or some other mismatch between the number of materials).

Hey Kajenx,

I mixed up my crashes. This is actually UE-40510, which is fixed in 4.15.

That looks right! I’ll have to update. Thank you.

Hey, could you take a look at this post: Dynamic shadows on foliage broken on half of terrain. - Rendering - Unreal Engine Forums

I haven’t heard from anyone for a few days.

Rendering/Landscape is not my specialty. If you think it’s a bug, you’ll need to move it/report it in the bug reports section and a Support Tech will take a look.

I think I may have tracked down an answer, actually. It looks like it’s this bug: Unreal Engine Issues and Bug Tracker (UE-20029)