Ok. Here’s some bad news. Now, all of a sudden, UE5 crashes upon just trying to save 1 material file once it imports this file. It imports the file without issue, I was even able to save a test UE5 file to see if .abc can be handled. Now, just like .fbx, I am at a complete standstill as UE cant do what it did literally minutes ago with the same exact file and startup. Is there a way to just make a uasset outside of UE? I cant rely on it anymore to make and save and if there is a manual way of doing this, I must use it unless 5.3 can handle this consistently. I am once again at a complete stand still because of this. Thank you for any help.
The Only fix I know, off the top of my head, is to manually go into the content folder and delete the last thing you added and then re-run the build. If it was a blueprint, go into the content folder and delete that blueprint. You should be able to open the file after doing so?
I don’t use alembic files. I have never really had issues with FBX and OBJ. As for manually just adding the file, I have never tried it. With the one file per actor feature…?
Ask away. If I can help, I most certainly will try.
If you do decide to delete the file manually and then restart, It might effect the build when you bake the game. I think, even though it’s erased, the editor will still look for. It might just throw a warning that it cant find the file, but I don’t know for sure.
Hello again. I wanted to be sure that alembic was a suitable replacement, and it was, so i started a new file, and it keeps getting stranger. The first time I imported it, it worked 100%. Second time, it would import just fine, but it could not save and crash. Third attempt, it just crashes after a while. I tried obj after and it just creates a new file for every frame. I don’t understand how a file works, and then it just doesn’t. I verified the files, but nothing pops up. Something has to be degrading with this. If you notice I did something wrong with the way I described my process, please tell me. Thank you again.
If it imported fine the first time, why did you need to import it again?
Because this is not yet the final model. I am testing to see if UE5 can even import my project before moving forward and I remembered this happening with my FBX so I wanted to make sure it wouldn’t happen to this file type, which it did.
Hear ya.
Ok. I am out of Ideas completely now. I hope this update bumps me up again for an answer from the community. I cant even restart my animation as that new animation also does not appear in UE5.3. I have downloaded Autodesk’s FBX Review and I get some funky looking things, but this gives no answers to me so Ill upload them here in case anyone else can figure it out. I also have tried importing the animation into UE4.26.2 and it works flawlessly so there is an issue with UE5.3’s importing. I also tried putting it in 4.26.2 and updating the file that way, but the asset just goes blank and crashes once I do anything with it, even just clicking it once. I waited for UE5.3 in the hopes this would be fixed, but it didn’t do anything different, but I also don’t get the errors in the Output log of bones already existing, but evidently, that was not the problem. I will also upload the images of the new 5.3 output log here of when I only import the FBX file. I have even deleted the bone structure of the problem bones and remade them and I still get the same exact problem. I also tried with the rebuilt bones to use only FK bones and use the copy rotation constraint in blender, which looked good as well as its bake before export, and the same exact problem persists. This has frustrated me to the point where I cant think of anything else that would seem out of the usual or even unusual as a fix. I have also uploaded a 7.zip of the blender file itself with only the animation and model. Thank you for any assistance. I really want to make this free experience but I am being held back by this problem.
Ohmu_014_Smol.7z (7.3 MB)
I will place everything that was posted here for speed.
The problem and some history:
I want to make this a free VR experience. I have an animation that worked just fine with all 468 bones in UE5, but is suddenly not working when I try to import the updated model and animation. For some reason, the front and side legs of my creature are not importing the keyframes from Blender 3.4. The FBX import for UE4 works flawlessly but I cant update any UE4 file to UE5 as the animation just crashes the system. The animation also goes back into Blender perfectly as well, even if I tried exporting it to blender after exporting from UE5.
What was tried:
Already checked system updates like drivers and uninstalling and reinstalling and verifying both UE5 and Blender. Tried looking into my Blender’s export process, which was fine as well as UE5’s Import process, which was also fine. The bone Hierarchy was accepted before in UE5 so that is not the problem. I also renamed the bones to ensure that they did not start with a number or have parenthesis which also did not work. The prior errors I got saying I had duplicate bones was also not true, the output log must see something blender does not export and UE5.3 no longer shows those errors. My transforms were also already good for both the model and armature. I have also tried baking my animation, but that does nothing too. I also deleted my morph targets and exported the anim alone but that did nothing as well. I also tried using Blender’s cleanup options, but nothing changed. I also tried using Alembic (.abc), but the files are too massive and just crash UE5.
I have looked up so many things that the output logs and the internet can provide, but nothing works. I have even tried AI, and that gave a few ideas, but they all failed as well. I have also tried restarting the animation and rerig this thing, but the same exact issue persists. Please help me with this. I cant think of anything else I could be doing wrong. If you need to ask anything, feel free to ask and I will provide you with as much as I can. Thank you.
Within the import settings you have an option to import the skeletal.mesh or animations.
Did you make sure the proper flags were set / are you able to import any animation at all before you bang your head some more against the mesh/skeleton ?
Likewise, when you export from blender you have to check off the proper options to have your animations actually export out.
Debug with something that isnt “this” and wrap.your head around how things are supposed to work fist - so then maybe you habe half a chance at debugging the other thing, should that really be at fault…
Hello. I have a few screenshots of my import settings as well as my Blender export settings. And yes, I have tried exporting and importing them separately with little to no difference. I have also tried different variations of both the import and export settings to see if something else would change, but I got nothing from it.
Also, sorry for the way I sound. I tried restarting this project in terms of the model and animation and ran into the same problem which just frustrated me (I tested it much earlier in my process so as to not completely remake it and have the same problem again. Glad I did as that was what happened.). I have also went back to look at the standard import/ export pipeline a few times already, including today and I still cant find anything I am missing. Thank you for any assistance.
Didn’t you mention you were using NLA strips earlier on?
If so, your export setting which you just shared has it checked off.
Also Only Deform Bones should generally be check on when exporting animations.
The only other thing to look into is making sure your scene scale is correct. Meters, .001 I believe.
I suggest you stop with this model if it still doesn’t work after trying these few changes, and follow just about any import/export mannequin tutorial.
Some now dated examples here for instance https://youtube.com/playlist?list=PLgRW1PMsJr5opFgtYb-1pyCvNxh29sYRH&si=ig9pX9O9Xbb69GRR
Once you are successfully getting the import/export process to work as it should, then go back to the model which isn’t working to figure out why. Maybe even start the animations from scratch with whatever you have lerned from the prior process…
I have also checked the NLA strips before and nothing changed. These are my export settings that I made a preset because they worked before on this model specifically as well as other models that still work, just not this one.
Also, I made a discovery after some intense research. Apparently, Blender reversed engineered the FBX file format and never got it officially from Autodesk. I went back to UE 4.26.2 and 5.1 to see what the output logs would give me there since 5.2 and 5.3 gave different results, and now, the animations work flawlessly in UE 4.26.2 and UE 5.1. Also, UE updated their FBX import SDK in between 5.1 to 5.2 and up. This means that the change has stopped my animations from working and I must now work in 5.1 unless 5.3 has a patch for this or 5.4 fixes it. Only problem I face now is that UE5.1 requires I rebuild the skeleton every time I start up the UE file for some reason, and save the animations (Which takes over 30 mins every time), so that’s fun. I also have to open the mesh file first to force UE5 to create the new skeleton first. If I don’t do that first, the new skeleton for the animations will not allow itself to be used in the animations later (This is confusing me why I need to do this, but that just means I have to do it all in one go, or just not shut down UE or my computer). Either way, I found the problem. If you know of a way to stop this from skeleton thing from happening, that would be appreciated. Otherwise, I found the problem, just not really a solution. Thank you all for your attempts to solve this problem, I appreciate it. I just wish I could have given an actual solution instead of a workaround.
Also, if you want to see the blender file I am working with specifically to see if you can find anything off, I will upload it again here. If you happen to find a different solution, I will update the solution here. Thank you all again.
Ohmu_014_Smol.7z (7.3 MB)
Not sure, but if you had tried my plugin you probably wouldn’t have had any issue.
The version of the FBX code that UE4 Curves was adapted from is from around blender 2.8 or so. Old enough and untouched by the latest updates that it’s worked consistently with anything I tried.
That’s possible but doubtful. They have to contend with retroactive functionality off of anything - including their own blender tools.
Aside from this post, no one’s complained in the forums about it this far, which on something so compromising is near impossible. As you can see there’s a sea of “this doesn’t werk” posts. Usually people come here just to complain… If the FBX import was damaged we’d be flooded by posts similar to that…
More likely, this means your animations were never being exported correctly by the export process. Or some similar snafu.
Sounds like you are already working in a compromised project.
What’s wrong with using an unreal version that just works like 4.25 ?
You can always migrate animations by upgrading the project version later on…
Again, I’m not sure you have. I think the problem is something in your export/import routeen And Or the way the file is set-up.
For one, when importing animations you don’t usually import mesh and materials at all. That gives you less options to fuss over too, so if you need to import animations, disable the mesh.
For 2, You ALWAYS select the existing skeleton in the skeleton option when importing animations.
For 3…
A properly exported file will actually NOT have the mesh import options visible.
This being an import example (albeit in 4.27)
Surely the 5.x ui is different.
The fact your export works in 5.1 but doesn’t in 5.2 is interesting either way.
To the point if you haven’t already you should provide it to Epic for testing and debugging their own mess.
Since I assume you want to be able to work (like anyone using the engine should want to?), then instead of bashing your head around the why (which you can but do you need to?) I suggest you stop using the beta trash they put out that’s worse than an EA release dubbed UE5 
(and yes, again, you can always upgrade a copy of the project with animations to be able to transfer them over later).
Hello again. I have checked my export import process from Blender to UE5 again and my presets still work just fine on other models and animations. I am exporting from Blender to UE5, and this addon says its for the other way around and it says its for UE4, so I don’t want to break anything with different versions. Ill check it out anyway as I saw at the end of the video there was an export thingy.
I also tried importing the assets one at a time like you said, but that throws only throws errors that flash and crash before I can read them.
Also, I have, for years, run into problems no one else has before (Even my instructors, who still work in the field with these software’s, and have decades of experience, have said as much. But we would usually solve the problems). I break every software I touch, which has helped before as I learn how to fix problems others might run into, but this is one I cant figure out.
I have deleted and restarted in fresh new instances of UE5 a lot already, so the odds of this being compromised should not be what’s happening (And yes, I did it again just now to be sure).
I have also exported and reimported my animation into fresh instances of Blender to export again (yes, very roundabout) only to have the same problems again. I have also tried getting my versions of working animations in UE upgraded from lower versions, only to have the animation asset go blank and crash UE without any errors thrown.
I am also using the official released versions of UE5. I don’t trust any alphas or betas as that may cause problems down the line once the official release comes in.
I’m really sorry that this issue has persisted for so long. I wish it was something simple and that I didn’t have to come here a lot, but its not. I already tried restarting with the model, rig, and animation, but I ran into the same problem again which really got to me as that has never happened to me before. I’m sorry again for all the hassle and thank you again for trying your best.
All official releases are beta at best.
They occasionally get patched officially, but the only way to find patches at reasonable intervals is to build from source off the non official releases.
Should you do that?
As an amateur, probably not.
As a developer working on an active project?
Always - but you should also be on a stable version, so not on ue5 without knowing the issues/risks/etc.
Maybe go at this on a step by step basis to determine at what point - and more importantly which action - starts the problem occurring.
First of, set up the log in a location you can access and read it.
Second, you probably need to install the engine symbols to figure out what is wrong with the engine itself if its crashing. You may already have them installed, but if you don’t the log will look/read as completwly useless.
Third, really an animation or an fbx import should not crash the engine, so you may in fact have ran into some unhortox change to the import system.
Without the log, this could be anything, so you need that to even start a bug report.
Look at the log/symbols first.
Go back to breaking the process you do which brings the error into play after sharing the error.
And again.
There’s nothing wrong with working on a stable engine version instead of the crapshoot that is ue5.
Hello again. Thank you for your assistance thus far. I wish we could figure this problem out, and I hope to figure it out, but I managed a consistent, working, decent, reproducible workaround. Ill still try to figure out the problem using the suggested “investigation” methods as I don’t want this to happen again and would like to know how this happened in the first place. I am using a .glb file type and its working now. I tried .glb before, but maybe it was 5.1 being strange, or I had strange things going on with the model at the time mid animating.
Just to help anyone who may have this problem and are seeking to make a workaround for such a strange issue, or just want to know how you could use a .glb animation, Ill include screenshots of my export and import settings. Only problem is the morph targets do import, but their keyframes don’t. I also have a strange issue where the animation jitters. If I find out how to fix the morph target and jitter problems, Ill edit it into this post.
Ill mark this as the solution for now and edit it later if I figure out anything else. Thank you again to everyone who tried to help!
Blender 3.4:
Blender 3.6:
UE5.3:
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