Just re-rigged and re-reanimated. Same error. 
Any updates? The plugin is completely un usable with this error. I can send you the test file if you need it.
The error occurs when exporting to FBX AFTER importing a custom animation following this guide: Extract animation key frames using Match Pose feature of Uefy 2.1 in Blender - YouTube
I have just tried this with Blender 2.83.6 LTS and Blender 2.90. I can match pose and export animations without any problems. Those errors you listed are from Blenderâs fbx exporter not from Uefy addon.
You can send a reply to the email with the download link and attach your file. I can take a look at it but this doesnât seem to addon related else it wouldnât work for me either.
I just completely re-installed blender and the plugin. Same error. Iâl email you the file.
ERROR SOLVED! Make sure to un-check âAll Actionsâ under Bake Animation in the FBX export menu.
Hi there. First off, this tool is amazing and help so much, many many thanks to the developer of this small little peace of gold <3.
I have 2 things i want to let you, and especially the creator know about.
First: There is a small bug on the right hand thumb if you create the uefy rig based on the ue4 manequin. The roll of the thumb_03_r is not correct and you have to fix this before you create the control rig, otherwise the thumb will deform weird.
Second: I have managed to get the rigify / uefy rig to work with the ue4 mannequin rig, so you can import animations directly onto the mannequin rig without having to retarget anymore afterwards. Beforehead it was only poosible to just import the rig and reuse animations built by others that use the mannequin rig, but with some small little tweaks it is possible to do your own animations directly for the mannequin, just if you where using the ART Rigging Toolkit from Epic for Maya.
The reason i wanted this to work is that retargeting in Unreal always breaks the ik bones, wich is kinda annoying. This is true for Paragon Animations and also if you rig with rigify and retarget the anims in unreal onto the mannequin, especially for those who are using the Advanced Locomotion System (ALS) this will be a hazzle to fix the ik bones, if even possible.
So i made it that i can rig in blender directly for the mannequin without the need of retargeting the animations and all the ik problems are gone.
I will make a video of the workflow soon if you are interested and if you @Waves are interested on how i did this let me know, i can provide help so you can build this into your next update 
Uefy 2.1.4 Released
This release fixes an incorrect roll applied to the outer most bone of the right hand thumb. The issue was only for the mannequin metarig. Any custom characters built using the human metarig are already correct.
You can use your existing emailed download link to get the updated version.
PS: Thanks for pointing out this issue, it was going to be in my next update.
Wow that was a fast update 
I have send you an email yesterday where i´m describing a very very specific problem. Can you maybe check your mail. I really wanna figure that one out to make the rig more suitbale for ALS.
Like i said, i´ve managed to make the rig fit the mannequin directly, but it creates a bug when triing to match pose from another character (retargeted to rigify via unreal). I wanna show you what i have done so you can implement it better into your system.
Hey there. I said i wanted to make a video of the process to add stuff to the rig so one can use the animations made with rigify directly with the UE4 Manequin rig. As it turned out, evertime i want to record a video of redoing the process, something goes wrong and i have to record it again cause i loose my concentration while recording. So let me try to explain the process with Text.
Let me first try to describe the problem. If you wanna animate with the rig like it is now and want to export the animation to unreal, you have to export the UEFY Rig to Unreal, import the animations onto the UEFY built rig. Which is fine if you want to use your own rig, but, if you wanna use for example Advanced Locomotion and add to it, you need to retarget the animations from the UEFY rig to the Unreal Rig, wich is kinda tideous and annoying.
What i want to achive is a solution to animate in Blender and export the animations directly onto the unreal mannequin so there´s no need of retargeting anymore.
Also i wanna use the match pose feature of the UEFY scripts to retarget Paragon Animations in Blender, wich already works like a charm, but, after the chages i´ve made to the rig, there´s a bug with it that i cannot figure out. and i hope that you Waves can.
First, you have to create the rig like explained in the video from Rakiz himself: âEasy rigging for UE4 Mannequin in Blender with Uefy 2.0â
After you are done with it make sure you save the rig in it´s own file and export it to unreal so you have the UEFY rig within unreal already, because we need that rig later for retargeting.
If done so, you have to go into the rig and rename / add a prefix to all the bones created by UEFY. (All bones that have the deform flag). In my case i have added the Prefix âUEFY_â
Now we need the original unreal Mannequin rig. You should already have it cause if you have done the Video mentioned earlier, you had to use it, if you dont have the rig anymore, you need to export it again from unreal as an FBX.
Now import the Mannequin Rig to Blender and leave the import settings like they are, DON´T use Automatic Bone Rotation!!! Leave everything like it is.
Add a Prefix to the new imported bones from unreal, for example âTGT_â.
Now join the mannequin rig with the uefy rig by first selecting the mannequin rig, then select the uefy rig and press CTRL+J.
For better visibility move the newly imported bones to an empty bone layer.
After that you have to parent every TGT bone to it´s corresponding UEFY bone with âkeep offsetsâ.
This makes sure every TGT bone moves with the parent UEFY bone, but, it also destroys the hirarchy the unreal rig had before, so we need a solution to get this back.
Let´s import the mannequin rig another time now.
Leave all the names like they are this time, because these will be the bones we will use for export and the name of the export bones should match the names of the rig in unreal, wich they do if you don´t rename them
Join the rig into the UEFY rig by selecting manneqin first, uefy last and press CTRL+J.
Now, you need to use Constraints, so the TGT bones will transform the Mannequin bones.
To do this, select f.e. the TGT_foot_l first, then select the foot_l and add a Copy Transform to the foot_l.
This has to be done for all bones.
After this is done, you should have to shadow rigs underneath the UEFY rig that move perfectly with the uefy rig.
Now you just have to enable the deform flag on the mannequin bones and disable the flag on the UEFY and TGT bones (Shortcut SHIFT+W).
And the last but not least is renaming the Vertex Groups on the Mesh so they match the mannequin rig by removing the UEFY_ prefix on every Vertex Group Name.
Now you should be able to animate with rigify and export the animation directly to the unreal mannequin.
Now comes the bug that i canot figure out.
If i take f.e. a Paragon Animation now, retarget it in unreal to the earlier created UEFY Rig, export the animation to an FBX and use the match pose feature from the UEFY script, the spine_fk bones get shifted in a weird way.
Hard to explain what exatly happens, i hope the screenshot will help.
What´s weird about this is, match pose works fine without the shadow rigs underneath, but, the shodwos rigs don´t mess up the hirarchy or anything else,
they are just childs of the stuff whats already there. And, the match pose feature, if i understand it correct, does not move the deform bones or anything else, it only moves the control rig, wich then move the underliing bones.
This is realy weird and i need help on this, i hope the explanation is good enough so you guys can follow, i don´t know how to describe this with less words and making a video of the problem is kinda hard too.
What i prefer would be some kind of dicord screensharing or teamviewer or something else to figure this one out together whatever you prefer. I think making this work will help many people out there animating stuff for unreals mannequin.
Best Regards.
AndrĂŠ
Here´s the image of how the pose comes out after using match pose on the shadow rigged uefy rigâŚ
Added a new tutorial for advanced character rigging with Uefy 2.
In this video, we take the Lava Knight character from the Elemental Demo and replace itâs skeleton in Blender with Rigify and Uefy 2. This gives it the same bone hierarchy as the ue4 mannequin and makes it simple to retarget animations and use blueprints in engine. At the same time rigify is fully functional in Blender so we can create new animations or make additional changes.
Since this character has a lot of additional armor bones. The focus in this video is on the process of adding extra bones to the armature beyond the basic mannequin hierarchy.
Iâm trying to set up a daz g3 character. Do you have a list for bone mapping. Iâm not sure what to do with some of the bones. DAZ has a hip and a pelvis. The pelvis is the parent of the legs and the hip points up to the spine. There a 4 spine bones and 2 neck bones. The legs have twist bones on the thighs and tha arms have 2 twist bones one on the upper arm and one on the lower.
Any help would be appreciated - Iâm using UEFY 2 Pro
WD
I do not use Daz so donât know exactly what to do. But the process is the same regardless of what the character source is. The character needs a 6 bone spine (head, neck, 3x spine, pelvis) and 4 bones in each limb (ignoring twists) for optimal results. If the character has more or less than the required bones you can edit itâs original armature to make it conform by adding or deleting bones and smoothing/updating itâs weight paint.
Once the character is fully rigged you can use the vertex rename tool to transfer original weights to the new deform bones as shown in my last tutorial above.
You will need to apply/delete any shapekeys on the mesh before starting the rigging process.
From what you describe you would delete one of the neck bones and join/smooth over itâs weight to the other. Same would be done for the rest of the spine. Sometimes I have seen characters that come with effectively two pelvis bones. One is used as central base with no weight paint and the other is used to skin the mesh. But in the Epic Skeleton there is only one pelvis and it also holds the weight paint so update your original armature to be the same.
You donât actually need to make changes to the spine in the original armature since we manually position the metarig spine bones. Just mark the locations where you might need to update weight paint.
Before you click âBuild Skeletonâ set the Twist value from âDefaultâ to âFullâ this will give you two twist bones per limb part instead of the usual one.
Alternatively
If you donât care about Epic Skeleton compatibility. You can also rig your character in Free Form mode. You can just build the metarig using supported sample types and make it match your original skeleton more closely to the way it is. With as many spine bones and twist bones as you specify. Just be mindful that Rigify also has itâs own requirements on how many bones can be in some of the sample types.
How do we add this addon to blender 2.9? When I attempt to install the .ZIP nothing happens.
I think you may be trying to install Uefy Script (Lite Edition). That is not an addon it is a standalone script used from the scripting panel. If you check playlists on my channel youâll find a list of tutorials for that version thatâll tell you how to use it.
Hello @Waves I am experiencing the following error:
I have fixed the metarig and added a few new bones following the instructions of the YouTube videos (the vertex groups are currently named as âu_***â), then I press Generate Rig and when I press Build Skeleton is when this error shows up.
Could you please help me? Than you
Some things to check:
If neck and spine bones have a space between them in the metarig. Turn off âConnect Chainâ for Spine.004 in Pose Mode -> Bone Properties -> Rigify Type -> Options
Make sure the new bones you add are parented to an existing bone.
Make sure new bones have a supported rigify sample type. Always use Rigify Button menu âAdd Sampleâ button to add new bones to ensure it. The list of supported sample types is in the FAQ section of Uefy 2 â Rakiz Random Rambling
Thank you for writing back so fast. I have checked all that: I fixed the neck and a bone that had the wrong type (it was a super_copy but it had to be a copy_chain) but it keeps happening.
I started using UEFY 2.0 and I could build the Armature normally (except for the new bones), then I did the âPreprocessâ and âVerifyâ steps and this error started happening. I tried updating to UEFY 2.1.4 but it kept happening.
I am using Blender 2.91 but I also tried 2.90.
These are the supported rigify sample types:
- basic.super_copy
- spines.basic_spine
- spines.super_head
- spines.basic_tail
- faces.super_face
- limbs.super_limb
- limbs.super_palm
- limbs.super_finger
- limbs.simple_tentacle
The other listings are mostly deprecated or aliases for one of the above. Also from Uefy v2.1 and above there is no preprocess.