Regression in animations in the last year

We were just informed that some of the animations that we have were broken. We are not sure when did this happened. We are working with cdn. These animations were working for sure at 2020

On the other hand other animations are working like

Could you help us understand what has changed with the animations in the last year and where the regression could be coming from?

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When you say from the cdn, do you mean from Because nothing changes there

Well technically we moved to 4.2 in April 2021 so yeah something changed :slight_smile:

can you repro the issue in the PG? (you can use version 4.1, 4.2 or 5.0 there)

It is almost impossible to help you without a correct repro (here is the entire list of changes: What’s New | Babylon.js Documentation (

When you say from the cdn, do you mean from Because nothing changes there


Thanks. I will check with 4.2.

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Also FYI we’ll be releasing Babylon 5.0 in April so might be better to upgrade all the way to 5.0 :slight_smile: we try our best to keep back compat but sometimes there have to be some changes :slight_smile:

4.2.1 is better :slight_smile:

Is there a way to ask the to work with a specific version of Babylon?

Because I just uploaded the file to and the animations are broken. It will be really convenient if we can try the sandbox with different versions.

The problem with the playground is that I have my files on a cdn that does not have Access-Control-Allow-Origin and thus we do not serve the files to I will look if there is a place I could upload it without introducing an Access-Control-Allow-Origin to my server but having the sandbox and being able to select the version of babylon there will be super helpful

I kind of demonstrate it on

It seems that for all versions available on playgroud this animation does not work. With is very strange as this animation was working for at least an year a few months ago.

I checked further with authors of the lego instruction and it seems the animation was previously prepared with one version of blender and was 3 weeks ago changed to another version of blender and I guess there is a mismatch in the way blender was storing the information about the animation and the way it is storing it now.

Will further check.

After testing with all versions of Babylon in the playground it seems not to be a babylon issue. I will be looking into where the issue is.



Glad to hear (Well at least from my standpoint ;)). Good luck with your bug search!

@kmitov you got me curious at “lego instructions” I can not wait to see what you are building :slight_smile:

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Oh, we’ve built it and plenty of people are using it. You can check out at and then one of the major platforms that is using it -


Niceee !!! keep up the good work there :slight_smile:

Just wanted to let you all know that the animation is now working - it was not a Babylon issue - FLLCasts | Bag 6 - Weight Machine - FIRST LEGO League 2020-2021 RePLAY

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