Question

Problem: When exporting to glTF for use in Godot, only the top animation track in the NLA editor is exported correctly. All other animations are broken and misaligned.

misaligned animation

I have three armatures in my project: Gun, Left arm, Right arm. The arms have child of constraint Bone Constraints on them, attaching them to Gun.

I have all animations pushed onto NLA tracks.

NLA Project

Things I ve tried:

Exporting each animation individually and combining them later in Godot. Clean animations break upon being pasted into a different AnimationPlayer Node.
Baking animations. Not entirely sure what the correct method is, but I ve tried baking in multiple ways, from object and pose mode, by removing and maintaining constraints, by overwriting actions and not, and it either doesn t make a difference or stretches out meshes beyond recognition.
Changing export settings. None of them seem to make a difference. "Use Current Frame" must be on.
Applying transforms. Well, applying transforms to the meshes does no harm, but nothing changes. Applying transforms to the bones sends them flying to every corner of the 3D view.
Clicking Apply on the Child of Constraint modifier. When I do this the object loses all animation.
Manually setting keyframes every frame. Does nothing.
Exporting without using NLA.

I suspect the Child of Constraint has something to do with how everything gets misaligned, especially considering an earlier project used no such modifier, and exported fine with around 10 unique animations. What I really don t understand is why only one of the animations get exported flawlessly.

I appreciate any and all help! Project Link (google drive)

Answer 1

I apologize for being 3 months late, however I went through a near identical issue, and I will post the solution that worked for me regardless for any people who might pass by through google and see this. I was working with Unity and not Godot for this project, though I imagine a lot of this stuff can be carried over to the problem that you have.

My animations were setup like this:

The left and right arm were separate objects being controlled by a single armature, and the weapon (a m1911 pistol) was a single object being controlled by a single armature.
The right hand was given a "Child Of" constraint to the pistol s root bone, while the left hand was constrained to the pistol s magazine bone.
I had one set of animations for the gun armature, and another set of animations for the arms armature.
The scale for all of the armatures and respective objects were applied prior to animation.

I managed to properly export ALL of animations to Unity like this:

Selecting the arms armature in object mode, switching to pose mode, selecting all bones, and then clicking "Pose" at the top.
Under "Animation", clicking "Bake Action".
When baking the action, ensuring that "Only Selected Bones" and "Visual Keying" were checked, and that "Clear Constraints"/"Clear Parents" was NOT checked. The other two checkboxes, as well as the start frame, end frame, and frame step settings are up to you to decide. The Bake Data was set to "Pose".
After applying the Bake Action, you will immediately notice the animation is not synced. Click on the bones with the "Child Of" Constraints, and set their Influence to zero by dragging the slider all the way to the left or clicking the X next to it. This should fix the issue.

After doing this, try testing if the animation works without the parent bone that the other bones were once constrained to with "Child Of".

If you have multiple actions, then change to the next set of actions you want to bake, set the influence of all "Child of" Constraints back to 1, and repeat the process of baking the action as written above.

To export, I then had each action for each armature as a separate NLA strip (That is, on the gun rig there was a Shooting action strip, a Reload action strip, etc., while on the arm rig there was also a Shooting Action strip, Reload action strip, and so on.)

I then exported with NLA strips into .FBX. this worked like a charm when importing into Unity. I had some duplicate animations coming from the left/right arm objects, but i just deleted those when i noticed them in unity.

Hope this helps somebody. And, if you re reading this, odds are you already found this playlist on youtube, but I ll post it anyway as it contains helpful export advice as well as general FPS animation tips and tricks. https://youtube.com/playlist?list=PLn8ROcXT8fZgjdv4w6FczF8ziXkavUxdu

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