Animation NLA blending issue

hello guys, I am having an issue with multiple NLA animations mixing up in
game. I need your help to understand how to play them “separately” in game.
There is 1 armature with multiple bones, all these bones are performing 4
actions (A,B,C,D) and some of these bones are shared between the actions.

I tried having 4 tracks with 1
strip each, all from 0-100 frames and been playing with Blending modes
“replace, add, multiply, combine” to mix them correctly. The issue is, I do
not want them to mix, but I need them to play separately since each track will
be connected to specific Hardware input. I also tried to split NLAs by using
different keyframes: and
obviously adapting the animation lenght in the XML. The result is the same, in
either cases the animations end up mixing and I can’t find no way to fix this.
also changing the extrapolation modes does not help… In blender all is fine
and it looks as wished, I just need to see it in game. I am using blender and
exporting glTF2 with mfs2020toolkit addon. ps. all animations exported one by
one work good in game, it is all about avoid mixing them once exported
together. Can anyone please help? Thank you.

I don’t know Blender but, I think the animation mixing is a kind of Blender-
specific abstraction, which other 3d programs also have but, when exporting
any game engine, they aren’t usually supported as they are, they must usually
be “baked” into a single timeline with all the blending being done at the
export level so, nothing of the original separate animations is left over in
the exported file, just a single timeline. Does the Blender export has
something like a “bake animations” option ?

Hi, I made a flag with multiple NLA track and I never had an issue. I think
you should not play with the mix What I’ll do: Add an armature, then add
actions but before pushing them I will add a track like this and select the
track With this method, I will
have an armature with NLA tracks and all the tracks. And inside each track, my

hi guys, thanks for the suggestions. The pose bake for all NLAs is partially
decreasing the mixing issue between NLAs. The issue is not solve though, NLAs
are still get mixed up even if they all are baked resulting into a wrong
animation behaviour. As an example, imagine you push the joystick and the and
the yoke moves but also the pedals because they have a bone in common (NLA add
up the values to each other). this is just an example and not the real case. I
expect some simple blending parameter to limit those NLA to mix in game but i
did not find any, probably the Gltf2 exporter from Blender does not export
such info correctly for the game. Any other idea?

Hello everyone, I need this issue to be solved, it is still not clear to me if
it is a game limitation, a blender / exporter limitation or I am simply doing
something wrong. Whenever there is an armature which has one or more meshes
parented to it (skinned or rigid) I end up having mixing animations in game. I
created a fake scene to show you an issue on a generic model: You can see in red, all input pieces (joystck,
throttle and pedals) In blue, there is a human with full body armature, this
means the bones will move the same mesh with every action but differently
depending on the called action. you can notice that while i move the pedals,
the arms are moving, or if i move the joystick. the throttle will move.
Separating this in 3 armatures would help but it is not the solution I am
looking for. In Blender all animations seem right (I also baked them so there
is no free interpolation). if you export animations one at time, they will
look correct in game. If you export animations all at once, this will look
mixed up in game (moving 1 arm will influence the other). I am sure the issue
is not the skinned/cloth mesh, becuase i am having the same issue with
simulated rigid parts (like engine) where some mesh is shared between multiple
bones. I also added a default state nla in the last attempt, the issue is the
same also without it I am uploading the blender file + the in game package. If any of you
could please help, it would be awesome. Thank you.

I do not know if it helps you, but do you know this thread:

Hi Karlo, thank you for your answer. Unforuntately that is not the issue, the
cloth itself works in game. The issue is when you have more than 1 NLA
animation assigned to the same armature, the 2 animations will mix up for no
reason in game.

I had this issue with jetway hoods and after much troubleshooting I found a
solution that works for me: Untick “Always sample animations” when exporting.
This tickbox wasn’t available in the msfstoolkit/blender2msfs, so I edited the
script files manually. I reported it as an issue and they’ve been very quick
to fix it. You can try the updated version with checkbox added in this thread:

That’s me (btronquo on github) that added the checkbox on the export windows
:slight_smile: @tonypezz , can you use the version that
WombiiActual linked and tell me if it’s working now with the checkbox “Always
sample animations” unchecked Cheers

Hello Luicid, first of all thanks a lot for improving the exporter, I gave a
try using this test scene i posted above with your modified exporter. None of
the options seems to solve the issue. using the old exporter, the result was
this one: moving the pedals, it would affect
the arms and moving the arms would affect the pedals (NLA mixing). using your
new option uncheck “always sample animations” the result looks like this:

If i uncheck “group by NLA
Track” before export, the exporter will fail to export from blender.
I also tried to check the
“export deformation bones only”, same issue. the test scene is posted in a
link above if you need to try yourself. Is there a way i can have a quick chat
with you to explain the issue better?, that is probably easier. Thanks a lot!
PS. thank a lot WombiiActual for your message here!

Sorry, it looks like we have very different issues, even if they seemed the
same on the surface. I tried your example by viewing the gltf in like I did with my jetway. I also
imported the asobo jetway hood to your blender file. To get the jetway hood to
have independent working animations I had to unmute all of the tracks and
export with always sample animations unticked. To get your character to have
independent working animations (in the gltf viewer) I had to do the opposite:
Mute all NLA tracks and export with always sample animations ticked. This of
course made the jetway animations blend together again. I even tried making
new animation tracks for your character the same way as the jetway hood. There
is definitely something odd going on. Attaching modified version of your
blender file that I tested this with. NLA_Mixing_example-

Hi @tonypezz , you’re very welcome, I made a fix this morning on the “Group by
NLA” action which will be released on this repository
later today. However, I made
several attempts and the animation is still broken but as I’m more like a
beginner in term of animations I will let you the plugin with my latest fix
to try by yourself if
you want Cheers, Boris

Any update on this? I have the same issue and weirdly it does separate the
animations on some armatures correctly while on others (also sharing bones) it
doesn’t. Haven’t found out yet what made the difference.

I got the mixing to stop by baking the animation not to pose, but to object.
Still I do have another issue of the animation always jumping back to a weird
almost but not quite Rest Pose when the animation value is close to 0. Weird.