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Failing Model Bones In A Chor


markw

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So apart from my copy of the Rear Window set being cursed, something I'm beginning to suspect, what rational reason is there for bones within a rig, in this case the LiteRig, to just stop working after a time and/or randomly rotate themselves?

 

The first casualty was the Lower Hip bone which died altogether on me, followed a little time later by the Neck bone randomly jumping out of sync with the head bone.

 

At first I was sort of able to work around these but now the neck thing is happening nearly every time I rotate the head.

Whilst it is possible to continue without using the Lower Hip bone, its pretty much impossible to animate without having control of the neck.

 

I must say though that if I open up a new Action or Chor using the self same model it works just fine :blink: Just not in the Rear Window Chor where I need it to work :angry:

 

Can this be fixed whist continuing?

Here's a shot of the neck issue for the curios;

Untitled2.png

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  • Hash Fellow
Can this be fixed whist continuing?

Here's a shot of the neck issue for the curios;

 

It looks mysterious! That's "Mika", right? If you could email me the Chor I could drop it in my Rear Window and see what happens.

 

theguy(at)brilliantisland(dot)com

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As Mark said, you shouldn't be animating with the neck bone (nor should it be visible) - but instead use the Head bone and Head Translator null.

 

If you haven't modified the literig, the neck bone is constrained to roll like the Head bone (enforcement = 30%), which could explain why it is rotating "mysteriously". Not sure why it would be a problem in rear window set, other than you accidently grabbed neck bone, and maybe have the pose "Hide extra bones" = OFF, which would make neck bone visible.

 

The lower spine is constrained to roll like torso 30%, and roll like lower hips 30%, perhaps you have "show lower spine" = ON (should be OFF), and you animated the lower spine? Normally you should be animating with torso bone, Torso Translator, lower hips bone, and Hips Null only.

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Good to see you back Nancy :)

Yes you and Mark are perfectly correct and normally the neck bone is hidden and you shouldn't need to touch it but I have shown it here so that the sudden jump in its "Z" rotation from one frame to the next when the Head Bone is turned could be better seen.

But now the only way I can get the Neck Bone back into line is to turn on the hidden extra bones and rotate it manually back to where it should be.

You mentioned the Lower Spine there Nancy and that also has played up once or twice and this "dodge" of tweaking the misbehaving bone worked for it but the neck is much worse.

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Can this be fixed whist continuing?

Here's a shot of the neck issue for the curios;

 

It looks mysterious! That's "Mika", right? If you could email me the Chor I could drop it in my Rear Window and see what happens.

 

theguy(at)brilliantisland(dot)com

 

Thanks for the offer Robert I will do that tomorrow.

Let me write some quick notes for you about it and I will also send you the character model with it as well.

By the way, those are good eyes you have there Robert but no, its not "Mika" but it is her hair!

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Can you save the chor action and post the model (no geometry) and action? I'd like to see what's going on.

Here you are Mark, I hope I understood your request correctly.

The ZIP file contains the Choreography actions for my character and the models used, with the mesh striped from them, just leaving the rig.

I'v put some notes in the file too.

Niki_Rigs_ChorActions.zip

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I'm looking at it. It is mysterious!

 

i can rotate the LowerHip bone fine up to 22:05 and then at 22:06 I can't anymore.

 

My first guess was that some pose has been turned on at that point that puts a constraint on the LowerHips, but i can't detect anything like that.

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A bit of snooping shows me that one of your Smartskins for the "back" has rotation keyframes for the Lower Hips bone.

 

That's unusual. I would not expect to want a controller bone (and a non-geometry bone in this rig, I think) like the Lower Hips to have anything controlling its motion other than the animator himself.

 

If I delete that bone from that smartskin I can freely rotate LowerHips in the chor again.

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Actually it was on "Torso". My theory is that at about 22:06 that Smartskin got activated enough to make a key on the LowerHips kick in and lock you out of controlling it.

nikiSmartSkins.JPG

 

 

 

I'm also wondering why there's a Smartskin for a "knee" that's is controlled by a "Torso" bone. I haven't looked to see what it does but that sounds like trouble.

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Well some of those Smart Skins are a bit of a mystery to me too Robert!

Most were done prior to running the "Instal" action for the LietRig.

The hands at the wrists were done after export from installing the LiteRig.

With all Smart skins I only did one side of the model and then ran Mirror SmartSkin plugin.

Despite numerous attempts at it I could never get a completely clean model export out the other end of the LiteRig "Instal" action. So maybe thats when some of these SmartSkins got screwed up too.

There were a lot of bones and stuff as I recall that were miss placed/assigned to the wrong bones etc that I had to go through and put back in their proper hierarchies after exporting.

See this thread for my adventures there...

I'v been looking through these SmartSkins my self now you've pointed them out Robert and my first thoughts are; the Knee Smart Skin now seems to have some tummy CP's (which should belong to Lower Hips) and some shirt CP's? assigned to it but no actual knee ones which have been given to Skin 1? Why/how is it in the torso bone? and the Right Bicep isn't showing any CP's assigned to it now!

 

So far I'v not found any Smart Skins for the neck bone and I don't recall making one but that's not to say there isn't another Smart Skin 1 for it hiding some place.

But its gone 2 AM here now, so I'll look some more tomorrow…

Thanks again for your help so far and good night.

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Ok, my opinion is that it's a rig design issue. Holmes' idea was to keep the bone count down in the rig, which causes some issues.

 

The problem is the neck uses an aim at constraint to the head translator and a roll like constraint to the head. These two constraints usually don't work well together in certain situations (it's sort of a gimbal lock issue). Most rigs deal with this problem by using a target bone to aim roll at.

 

You can fix the issue by adding a target bone, child of the head bone, removing the roll like constraint and adding an aim roll at in the main constraints relationship. After fixing the model, if you decide to fix it, make sure you delete the keys on the neck in the chor action.

 

You may even have the same issue with the lower spine at some point.

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The problem is the neck uses an aim at constraint to the head translator and a roll like constraint to the head. These two constraints usually don't work well together in certain situations (it's sort of a gimbal lock issue). Most rigs deal with this problem by using a target bone to aim roll at.

 

For my literig implementation in my Lothario character, the neck bone is aimed at the head bone (not head translator), and rolls like the head bone, and the head bone is translated to the head translator null. I'm not sure if I changed that from what Holmes might have had, but it hasn't given me any problems.

 

(I just looked at Niki models and it appears they do the same as what I did, so I'm guessing I didn't change it)

 

I think the problem might be related to turning on/off "Hide extra bones" pose and animating with the neck bone.

 

I also notice some weird keys in choraction 1 for Niki13, for the head translator where it is made active at different frames - but they are out of sequence??? and there are some keys to ignore fog? I would delete all those keys, as well as delete all channels for the neck. I also notice many channels (other than head translator)that don't begin at frame 0 - it looks to me like perhaps the channels were moved?

 

EDIT:

I'm not a LiteRig connoisseur so I'm not sure what the proper time to do smartskin is in its workflow.

 

Best order is after assigning control points normally, and doing any weighting, then do smartskins, then install controls. But my guess is one can also do smartskins after installing controls.

 

I am noticing also that there are funny custom constraints (not standard in literig) in niki13 on the right bicep and left bicep as well (probably shouldn't be there?)

funnychannels.jpg

Edited by NancyGormezano
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Sorry Nancy, you're right (looking through too many relationships), my mistake, it is the head it is aimed at. But, this makes no difference in my opinion.

 

I have tested adding the target and the aim roll at constraint, it fixes the issue.

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Perhaps Holmes will chime in. When i move the head the neck behaves very erratically and I think there must be some unseen factor here. I'm doubtful Holmes would have not noticed this while he was developing it.

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I still think there is some unexpected factor making that neckbone misbehave. We may discover it yet.

 

However, here is a suggestion for an alternative way to control the head that is simpler and faster to work with.

 

FYI, The head translator null in the literig was included to allow some pseudo squetching of the neck in any direction, just like the torso translator is used to pseudo squetch the torso in any direction. Neither null has any limits, so it is up to the animator to squetch, translate it so that it looks good for the character.

 

I've used both of these translators and loved this feature of the literig. Works best of course for cartoon type characters. I've never had a problem with using either translator.

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I think that all could still be controlled with just a head bone and separate translate controller wouldn't be necessary.

 

And I totally agree: All that's really needed is head and neck bone (no controller even), and one can also have some pseudo-squetching by scaling the head bone

 

That's the beauty of lite-rig. It's the easiest rig to hack, modify, because it's lite, simple, "easyish" to understand. I believe Holmes would probably say that was part of his intention in creating it.

headneckwithsquetch.jpg

HeadNeckWithSquetch.prj

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Hello all and thanks for the ideas and help :)

Robert, the vid was informative as always and I have altered Niki14's head to that method and in fact I'v just finished redoing the head animation which took very little time.

For now I'm leaving the first part, with Niki13, alone as I'm done working with that model and will fix it later if I have time.

I probably need to do the smart skins again too for 14 but surprisingly they do still seem to work even if some of them are "stored" in the wrong places. So something else to do if time permits.

 

Mark I wanted to try your idea for fixing the head, on the Lower Spine like you suggested, as its played up a bit the same as the neck did, but I got confused :blink: and thought it best to leave it alone until you could clarify it for me.

Could you walk through the steps for changing that?

Here's what the constraints are at the moment on the Lower Spine.

Screen_shot_2012_05_01_at_21.12.19.png

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Does changing the head rig solve the neck jumping problem?

 

 

One thing I'm not clear on is why you need a different version of Niki in there. Why not use a second instance of the same one, unless we know what's wrong with 13, in which case we coudl fix it.

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Here's niki14 with the added targets and constraints.

 

To fix your model (since I don't have a version with geometry) open this model and your model in the same project. Go into bones mode on the fixed model, from a side view you will see 3 target bones. Select each bone to see their location (take note of their parent). From the PWS select the bones and drag them to their parent bone in your model (hide them afterwards). Once you've done that, drag and drop the relationship folder from the fixed model to your models name, this will update the relationships. You'll need to go into where you smartskin relationships are and delete the relationship for the torso (dragging and dropping the relationships folder does not delete the smartskin).

 

In your chor action, delete the neck and lower spine from the action in the PWS. (This is for your original chor action you posted)

 

Let me know if this fixes the issues you were having.

Niki14_Mark_Fix.zip

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Does changing the head rig solve the neck jumping problem?

 

 

One thing I'm not clear on is why you need a different version of Niki in there. Why not use a second instance of the same one, unless we know what's wrong with 13, in which case we could fix it.

It maybe early days yet but in redoing the head moves last night, the neck bone behaved perfectly and meekly followed its controller!

 

Well yes your right Robert the animation could all be done with one model and it would have been… but because Niki started playing up during the animation and the end of May fast approaches, I hoped for a quick fix and thought I might just kill two birds with one stone...

 

1; As parts of 13 stopped working properly and I didn't know why (maybe it was just that model) the easiest option seemed to keep what I had already done but dump the model and bring in a new version for the rest and see how well she fared. We now know that was never going to work!

 

2; I was also having problems with the left foot controls. Don't get me wrong, they work just fine but somehow I had managed to manoeuvre that leg in such a way, so that the controls were nearer the right foot now than the left and I couldn't find the right combination of moves and turns to bring both foot and controls back together again and it just confused me every time I wanted to animate with the left foot controller. (I confuse easily ;) )

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Here's niki14 with the added targets and constraints.

 

To fix your model (since I don't have a version with geometry) open this model and your model in the same project. Go into bones mode on the fixed model, from a side view you will see 3 target bones. Select each bone to see their location (take note of their parent). From the PWS select the bones and drag them to their parent bone in your model (hide them afterwards). Once you've done that, drag and drop the relationship folder from the fixed model to your models name, this will update the relationships. You'll need to go into where you smartskin relationships are and delete the relationship for the torso (dragging and dropping the relationships folder does not delete the smartskin).

 

In your chor action, delete the neck and lower spine from the action in the PWS. (This is for your original chor action you posted)

 

Let me know if this fixes the issues you were having.

Thanks Mark I'v redone the lower Spine now with your fix and so far all seems good.

So she now has Roberts head solution and yours for the spine. I just need to redo some Smart Skin around the tummy I think and then she's good to go again. :)

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