Rigged mesh unwanted deformation around shoulder area

[Hieronimos Audeburgh]

Hey all!

for some reason the besagew on my rigged mesh armour set keeps showing unwanted deformations (I'm using Blender 2.64).

I tried various things: only weightpainting the shoulder (as it should move at least a little with the shoulder/upperarm's movement), weightpainting it to the shoulder and collar, weightpainting it to the shoulder, collar and chest, toggling 'preserve volume', toggling 'Bind To: Vertex Groups', toggling 'Bind to: Envelope Bones' (and all the combinations between these). Still I keep getting the same result shown below:

The Besagew is supposed to be perfectly round, but it keeps deforming into an oval shape no matter what I do. How can I make sure that the round shape is preserved? It's alright if it sticks into other parts of the mesh, even that it becomes a little bigger or smaller, but an oval shape just won't do... Any suggestions?

Thanks!

P.S.: this problem only occurs around the shoulder area: all other pieces of the mesh (whether round or not) are working perfectly.

[DerpWolf]

Weighting them to single bone (weight 1.00) should do the thing. Are you sure there weren't other vertex groups on besagews when you tried to weight to Shoulder exclusively? BTW, Preserve Volume is the Blender specific feature. I bet it cannot be exported to other programs.

[Hieronimos Audeburgh]

Hey DerpWolf! Thanks for your reply!

 

You mean the value here in the object tab right?

 

All the other vertex groups/bones are set to 0.0.

I checked all bones in weight painting mode and everything is full dark blue except for the shoulder bone (full red)... 

Still no luck though... The round shape keeps distorting into an oval shape

 

'Preserve Volume' seems to be supported by SL; I used it a couple of times - although that doesn't help anything in the case of this specific problem though.

[Sassy Romano]

Easy one.  mShoulder is the upper arm (not what i'd call the shoulder which LL call the Clavicle)

When you rigged, the model was in T pose, in your picture the model is with arms down so as the arms came down, the mesh has been distorted, that's what it looks like to me anyway.  I'd still question whether there are any other weights there too.

It looks to me like mChest would be a better vertex group to weight to anyway.  Admittedly, I know nothing about armour but it doesn't look like that bit needs to move and certainly rigging that to mShoulder in t pose and hoping it will work for all positions of the upper arm seems to be optimistic if not downright challenging!

[Hieronimos Audeburgh]

Hey Sassy! Thanks for your reply : )

"I'd still question whether there are any other weights there too."

That was my idea also, at first anyhow... But after checking every bone in the blend file multiple times I can say with pretty great certainty (I'm a rigging noob I must admit though) that the only bone influencing the movement is the shoulder bone.

I had hoped I could get it to work with the arm rather than the chest since the part would move better with the rest of the pauldron... But maybe I'm trying to do something that's just about impossible. I presume that if I do get it to work with the arm then I'll have to weight it to the chest also a little to get the right movement, which without a doubt is going to cause distortions again. 

Which brings me to the question: isn't it possible to have a piece of a rigged mesh move with multiple bones without distorting the shape?

Thanks again for your reply anyhow!

[Gaia Clary]

i guess the deformation of the circle is small but noticeable ? And the distortion only occurs when you wear the nesh, but not when you rezz it on ground ?

If that is the case, then you probably need to compensate the "wrong scaling" by slightly deforming the circles in Blender in the opposite direction. So that when you wear the mesh, the original circular form turns back.

[DerpWolf]

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Hieronimos Audeburgh wrote:

You mean the value here in the object tab right?

 Yes, you can use this menu. Select all desired vertices and hit Assign. Though not sure what is your problem. Usually such deformation occurs when there is more than one weight. Does it look the same in Blender and Second Life? I am asking because I was not able to reproduce your bug in Blender. Weighting to single bone works just right.

http://gyazo.com/013380e6353867d528659eee904300c8

 

[Hieronimos Audeburgh]

Gaia: Ofcourse! I hadn't thought of that solution yet! That little trick will get it within the limits of the acceptable at least! Thanks a lot! : ))

 

DerpWolf: In Blender it looks just perfect: no distortion. The oval deformation only occurs after upload in SL

[DerpWolf]

No idea then. Seems like something I do not know yet. Could it be related to some individual settings of your avatar?

[Jake Koronikov]

One more trial to solve this:

If I understood right, you have rigged this to mShoulder. So, it is not fitted mesh...but the avatar shape slider "Body thikness" inworld affects somewhat the mesh shape on that area even without volume bones.

Maybe try to play with your avatar "Body Thikness", "Shoulder width", "Torso lenght", "Body lenght" and so on sliders inword - after you wear the mesh. Or change your shape to default male avatar inworld. I would predict that you will see some change from oval to round

[Gaia Clary]

Here is the reason why it (probably) happens:

The "default skeleton" that you see in Blender (when you use the avatar.blend or the Avatar workbench for your work) is actually provided in the "SL rest pose" while what you see in SL is the "SL bind pose". These two are slitghtly different and when you wear your mesh, then the SL animation system transforms your mesh from the Rest Pose into the Bind pose.

Unfortunately the biggest deformation happens on the arms and chest. this would explain why a circular object deforms into an oval object when you weight it to the chest.

I must admit that this is just my guess how it is. At least that makes the most sense to me after digging on this particular issue since a whole lot of time. But actually the true technical reason might be different. Only nobody ever wanted to tell me the truth so i have to make my guesses :matte-motes-bashful:

Here is an article that i wrote about the SL skeleton. maybe that helps you somewhat more:

    http://blog.machinimatrix.org/avastar/the-opensim-skeleton/

And here is an excerpt from a longer video about SL rigging that demonstrates what happens:

    https://vimeo.com/88041161

 

[Hieronimos Audeburgh]

Thanks for all your replies... I'll keep you posted, lol : P : )

 

DerpWolf: when you were setting the parent for your cylinder (control+P), what type of parenting did you use?

[Jake Koronikov]

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Hieronimos Audeburgh wrote:

Thanks for all your replies... I'll keep you posted, lol : P : )

 

DerpWolf: when you were setting the parent for your cylinder (control+P), what type of parenting did you use?

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I would propably go so that I would export the shape I use inworld. Then I would import that shape .xml to Avastar. Then I would design the roundiness according to the real body shape that will be used.

After this kind of a workflow the final mesh will look exaclty same in blender and inworld. And this is due to the fact that vertices weighted to mShoulder bone are affected by avatar shapes sliders inworld. Gawd only knows how much the influence is..but there definetely is influence

[DerpWolf]

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Hieronimos Audeburgh wrote:

 

DerpWolf: when you were setting the parent for your cylinder (control+P), what type of parenting did you use?

In this example, there is none. Just Armature modifier. But before exporting I'd need to set parent to Armature (Empty Groups), because for export to SL, mesh needs all bone groups present.

 

[Hieronimos Audeburgh]

Jake: I haven't got any experience with avastar yet and I didn't know it was actually possible to export my shape... So that is some very good information to follow up on... After all, it was 'influence' enough to keep me busy for hours : ) Thanks! : )

DerpWolf: I still get the same issue so I guess it must have something to do with the issues Jake and Gaia brought up. Thanks for your help though!

 

[Gaia Clary]

Just to mention this... If you use Avastar and if you use the same shape in SL and in Avastar, then there should be no distortions.

I did not mention that because i thought you where not using Avastar.