Animations in Unreal twist the model wildly (using Unreal mannequin's standard sekeleton)


I have modelled a custom mannequin and created a skeleton for it in Blender. The skeleton copies the Unreal’s mannequin’s skeleton perfectly (hierarchy and bone names all the same).

When I import this model and select the Unreal’s standard skeleton to use with it, it does not complain. But when I run an animation on this model, it gets twisted so much that it gets basically unrecognizable. I thought I has something to deal with the initial transform of the joints when imported and tried exporting from Blender with various different settings but that did not help.

Here is the linkto the stack question with illustrations, it also contains .fbx file with my model/sekeleton.

really hope you can help me out with that.

Thank you!

I’ll have to try the fbx file, but offhand I would say your weight paint is at fault.

How does the mannequinyour model animate in pose mode within blender?

[USER=“3140864”]MostHost LA[/USER] thank you for taking time to answer. I have tried moving bones around both in Blender and in Unreal, and it works perfectly.

I’ll check your fbx in the AM. I have never seen that much distortion before.

Your re-targeting pose is the principal reason this doesn’t work.
Aside from that you have some serious weight paint issues.

This is a really bad pose approximation in which I literally just moved the bones in editor.

You need to export the mannequin base pose (the A pose) and create an animation for your character that uses the exact same rotations - not translations. so that the end result is visually the same - aside from translations.

Unbelievable! Thank you so much for making the effort for a random stranger! Really really appreciated.

I cannot check in the next hours because extremely busy at work but I will try to replicate what you have done to get comparable state to understand what exactly was at fault.

I thought my weight paint was correct because I was able to deform correctly in Blender… well, what do you mean with moving bones in editor? You mean that I must kinda find the right position of a bone in Unreal editor until it starts to look better?

Okay… and then create an animation that uses the same rotations… I think I understand… you mean ignoring translation because models look slightly different but only applying rotations… the problem is - in this case I wanted to make use of Unreal’s animations. otherwise I would have done my own skeleton and animated correspondingly

… ‘export the mannequin base pose’… do you mean exporting the base pose from Unreal 3rd pers tempalte? and then only apply rotations to create *my *animations using the Unreal’s animations? is it what you mean? sorry, I really just started recently with Unreal

export the unreal skeleton.
use it as a guide to get the rotations right.
the poses should look very similar to each other for retargeting to work.
off you base model, the legs are too close, so offset at the thigh rotation.
the afferma need to be rotated to match as well.

So, I’ve tried adjusting the bone translations/rotations in Blender and got something comparable to your result…
there were two issues actually:

  • first, the units were wrong - this is the major reason why the model looked so stretched - after I scaled x100 in Blender, it started looking better except the model was still twisted due to incorrect base pose translations - that is obviously a bug in Blender or at least something not user-friendly or obvious
  • second, the base pose translations/rotations as you explained. After having adjusted the base pose of my character to Unreal’s skeleton, it started looking *a little bit *better…

I wonder whether it is not easier to get a couple of animations done from scratch rather than retargeting…

I’ll post the answer and my process in SO in some time, anybody having the same issue please take a look in the link provided above

[USER=“3140864”]MostHost LA[/USER] thanks again for your help!