There's something funny about character animation blending

[Gugis]

I don't know if it's relevant issue, but I noticed something strange about skeletal animations blending. When animationBlending is set for skeleton there's strange squeezing in and squeezing out while transition between two animations is happening.

Here https://gyazo.com/f32c07d151b9bae3afcc1825f1871361 (it's best seen looking at character's head).

Is there something I can do about it? I don't know if it's a bug or I messed up something with animations, but  without blending animations looks fine.

http://www.babylonjs-playground.com/#1WUHAN#1

Hold W key to change animation

[Raggar]

It makes it a lot eassier if you post a Playground example, as otherwise, people will have to blindly guess what the problem 'might' be

[Gugis]

15 minutes ago, Raggar said:

It makes it a lot eassier if you post a Playground example, as otherwise, people will have to blindly guess what the problem 'might' be

I don't know how to load babylon scene in playground from external url.

[aWeirdo]

@Gugis

Just use a url, instead of a relative path;

http://www.babylonjs-playground.com/#U6CMY#1

[Gugis]

27 minutes ago, aWeirdo said:

@Gugis

Just use a url, instead of a relative path;

http://www.babylonjs-playground.com/#U6CMY#1

It gives CORS error.

EDIT: Nevermind, I uploaded it to github and it works

http://www.babylonjs-playground.com/#1WUHAN#1

Hold W key to change animation

[aWeirdo]

@Gugis where is your file hosted? can you upload it to github?

[Gugis]

16 minutes ago, aWeirdo said:

@Gugis where is your file hosted? can you upload it to github?

Yes it works with github. Thanks

[GameMonetize]

Your PG seems to work well  Did I miss something?

[adam]

The bones aren't maintaining the correct scale while tweening.  Look at the head here:

https://gyazo.com/f32c07d151b9bae3afcc1825f1871361

[GameMonetize]

oh yes..Interesting.. Tweening is done with a simple lerp between values:

https://github.com/BabylonJS/Babylon.js/blob/796920ee3b9572925745e066ce609e052a613de7/src/Animations/babylon.animation.ts#L489

I'm not sure how we can help fixing your issue

[GameMonetize]

Are you sure your animation is correct? (I mean the head is the same in both poses?)

[adam]

I think this could be related to this issue:

 

[GameMonetize]

To fix the blend issue we moved to Lerp: https://github.com/BabylonJS/Babylon.js/blob/master/src/Math/babylon.math.ts#L2831

But when I check the animation I'm almost convinced that parts are squezzed because they are not stricly the same between two animations

 

[Gugis]

I checked skeleton and mesh in blender and it looks fine. Squeezing happens only when blending is happening. It squeezes in when transition starts and squeezes out before transition is ended. If that's not Babylon bug, maybe Blender exporter has something to do with this?

[gryff]

@Gugis : can you post the .blend file with the two animations so that I can take a look?

cheers, gryff

[joshcamas]

I think this is an export problem. If you completely disable blending, the problem persists - the animation seems to not end on the same frame as it starts, or a frame you don't want is somewhere inside. As gryff said, a blend upload would be the best.

[Gugis]

1 hour ago, gryff said:

@Gugis : can you post the .blend file with the two animations so that I can take a look?

cheers, gryff

https://github.com/Gugis/test/blob/master/assets.blend

32 minutes ago, joshcamas said:

I think this is an export problem. If you completely disable blending, the problem persists - the animation seems to not end on the same frame as it starts, or a frame you don't want is somewhere inside. As gryff said, a blend upload would be the best.

That's because Blender exported animation ranges wrong. Before there was babylon file with fixed animation ranges, but now I have just updated with this file.

[gryff]

@Gugis : TY for the file

I have taken a quick look and the Blender file seems ok - apart from the 65 bones!! Typical of many Mixamo models - 42 bones in the hands which are basically not animated over the frame animations. 

One possible issue that I did notice when I did an export from Blender and looked at the .babylon file:

"ranges":[{"name":"attack_with_shield_moving","from":0,"to":40},{"name":"idle_with_shield","from":50,"to":127},{"name":"run_with_shield","from":140,"to":162},{"name":"walk_with_shield","from":170,"to":204}]

That line defines the frame ranges for each animation you are using BUT here are the frames for the head:

{"name":"mixamorig:Head","index":5,"matrix":[0.9739,0.0085,-0.2266,0,-0.0746,0.9557,-0.2849,0,0.2142,0.2944,0.9314,0,0,0.0679,0.0225,1],"rest":[1,0,0,0,0,1,0,0,0,0,1,0,0,0.0679,0.0225,1],"parentBoneIndex":4,"length":0.269
,"animation":{"dataType":3,"framePerSecond":30,"keys":[
{"frame":1,"values":[0.9938,-0.0614,0.093,0,0.0961,0.895,-0.4356,0,-0.0565,0.4418,0.8953,0,0,0.0679,0.0225,1]},
{"frame":2,"values":[0.9738,-0.1798,-0.1394,0,0.1298,0.9422,-0.3088,0,0.1869,0.2826,0.9409,0,0,0.0679,0.0225,1]},

Notice no frame zero !! Similarly :

{"frame":39,"values":[0.8909,-0.1491,-0.429,0,0.0859,0.9829,-0.1631,0,0.446,0.1085,0.8884,0,0,0.0679,0.0225,1]},
{"frame":40,"values":[0.9124,-0.1126,-0.3935,0,0.0796,0.9919,-0.0993,0,0.4015,0.0593,0.9139,0,0,0.0679,0.0225,1]},
{"frame":51,"values":[0.9124,-0.1126,-0.3935,0,0.0796,0.9919,-0.0993,0,0.4015,0.0593,0.9139,0,0,0.0679,0.0225,1]},
{"frame":52,"values":[0.9126,-0.1145,-0.3925,0,0.0813,0.9916,-0.1002,0,0.4007,0.0596,0.9143,0,0,0.0679,0.0225,1]},

No frame 50 . And it is the same with frame 140 and 170 - they don't exist. If I play just one animation in the range I get a jerk/twitch as it loops

@JCPalmer : any thoughts Jeff?

Will investigate more later this evening

cheers, gryff

[Gugis]

Yes I have noticed that too. Also i have to reapply scale for objects over and over again before exporting to .babylon otherwise animations become distorted. Do you think these are related to squeezing problem?

[gryff]

@Gugis : Well I took another look at your file and exported it*** - and used it instead of your file in the PG

My Playground

You will noticed I made some changes to your script:

1. Changed the ArcRotate parameters and added a line to control "wheelPrecision" so it zooms with some control.

2. I REMed the line #32 about the scaling as it is not needed because of 1.

3. The big change - line 31 - I changed the blending parameter to 0.25

It looks fine now .

And just so you can check easily, I made the same changes to:

Your Playground

It looks fine too.

*** I did make a couple of changes to the blend file.

1. I changed the default Sstart frame" to 1 under the "Camera tab" in the Properties Panel

2. In 3D Window, I hit N Key to bring up the 3D window properties, then "Selected" the Armature in the Scene Outliner panel and put the Armature into the "Rest Position". Note the Transform settings in the panel that was opened in the 3D Window. Now, I "Selected" the "man" mesh - note the -ve signs.. So I applied the Location and then Rotation and Scale. I always like the Transform values to be identical!

And I changed the "Start" values for the "Ranges"  manually in the resulting .babylon file.

What do you think ?

cheers, gryff

[Gugis]

10 hours ago, gryff said:

@Gugis : Well I took another look at your file and exported it*** - and used it instead of your file in the PG

My Playground

You will noticed I made some changes to your script:

1. Changed the ArcRotate parameters and added a line to control "wheelPrecision" so it zooms with some control.

2. I REMed the line #32 about the scaling as it is not needed because of 1.

3. The big change - line 31 - I changed the blending parameter to 0.25

It looks fine now .

And just so you can check easily, I made the same changes to:

Your Playground

It looks fine too.

*** I did make a couple of changes to the blend file.

1. I changed the default Sstart frame" to 1 under the "Camera tab" in the Properties Panel

2. In 3D Window, I hit N Key to bring up the 3D window properties, then "Selected" the Armature in the Scene Outliner panel and put the Armature into the "Rest Position". Note the Transform settings in the panel that was opened in the 3D Window. Now, I "Selected" the "man" mesh - note the -ve signs.. So I applied the Location and then Rotation and Scale. I always like the Transform values to be identical!

And I changed the "Start" values for the "Ranges"  manually in the resulting .babylon file.

What do you think ?

cheers, gryff

Thanks gryff. You increased blending value so transition happens faster and it's harder to notice the glitch, but that does not solves the problem :/

[adam]

I changed Matrix.Lerp to Matrix.DecomposeLerp here on line 39:

http://www.babylonjs-playground.com/#1WUHAN#4

Does anyone know why that would cause the model to invert during blending?

[GameMonetize]

Because the decompose can decompose to non linear values between calls

[JCPalmer]

10 minutes ago, Deltakosh said:

Because the decompose can decompose to non linear values between calls

So it this why you switched away from decompose method from Lerping?  You could not remember the reason in the earlier topic @adam referenced above.  This would explain why I never could find a problem in QI.  There I store everything decomposed already.  I was doing it for performance reasons, but guess there is also another reason.

[GameMonetize]

Yeah I remembered it when I saw the PG created by Adam