MHX converted rig knee pole not follow IK foot move (corrupted IK) anymore.
Issue #453
resolved
With any IK foot,, when I move FK foot,, usually knee try to follow the move.
Then I tweak IK pole to adjust the Knee rotation. (direction)
Current MHX converted rig Knee not follow IK foot at all. Knee rotate with the with IK foot transform to strange direction.
you simply compare Rig fy IK foot move and MHX Ik foot move, and check how knee pole change.
I have never seen such behavor for MHX rig, or any IK rig for IK foot and knee.
Comments (21)
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reporter
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This is related to
#421#439I don’t seem to experience ik flipping with rigify. You have to optimize the rest pose for ik first, as provided in the finishing panel.
edit. As a side note for Thomas, I see that rigify doesn’t get bone shapes for the face. It would be nice to get bone shapes the same as mhx does, a simple circle would be enough at least to avoid the sticks.
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reporter
The problem is to solve IK flipping issue, current MHX rig pefectly broken to get usual IK animation. I have never seen any IK human rig, which knee rotate around with foot IK move. it need to follow with IK foot .
It is not related JCM or show hidden slider as option at all, . ALL animator know which slider need to use for animaation. so just show hidden JMC slider as UI, it is not problem at all. They simply avoid it when they need not use it.
You may need to ask your course teacher, then show 2 rig how work (MHX before and after) then ask which you may hope to make animation with use IK . Current way is pefectly broken to pose IK correctly. If mhx rig keep current way about IK, no one may use it to make simple IK animation. it is so clear wrong behavor.
I do not hope to test those things, untill most of morph problem may solved as default rig, then did not concern what have changed. I have seen MHX stable work, then if it was improved more , it is good enough. But current way actually broke usual IK foot system.
As for me,, the old rig was far better to pose with IK foot. I only need to care flip issue. I can show you how rig-fy cause flipping but it not matter now, I am talking current corrupted MHX IK rig. I test it with default G3, and no morph. it actually broken for me.
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reporter
Then Alessandro, all things need to consider Pro and Con.
If you do not like to show hidden systematic Driver as UI (and prop which adjust JCM) you can hide it. there is nothing wrong to remain it as UI. because you have option show or not. then at same time most of Daz user, understand, we only tweak JCM slider (hidden) when we need it. So it is actually no problem.
I do not think Thomas make add on for user who do no know how JCM work. If I make document for man who do not know JCM meaning, of course I may say “ basically you do not need to tweak Hidden driven value untill you know how it work)
I ask those things, to make it work as same as daz work about driven value. so if you do not use it do it as you like. But I use it when it need. then ask add slider as option. because if there is no raw prop. I can not make it work easy. as same as daz. then if user not adjust JCM in daz studio, they do not do it with blender. you need not to use it. so I really do not need to care user about the JCM things.
It never force others to change JCM effect when you make pose or animation. it is perfectly depend user.
This rig structure problem is not. there is no option. I really do not know Thomas actually test it or not. then if he test it, and think it work better than before,, I ask Him please keep old rig as option. so I can choose MHX still.
Btw I really do not think, current way is OK at all. then the problem is far worse than flip bone issue. If rig-fy show same behavor must report it as heavy bug.
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You can use the pole to pose the knee as you wish. Then you are right that the knee doesn’t align automatically with the foot, but this doesn’t mean that “the current mhx rig is perfectly broken“. This was done to avoid ik flipping.
Then if you “only need to care about the flip issue”, then this means the rig doesn’t work fine because the ik chain is unstable. I guess we don’t agree that ik flipping should be avoided. As for rigify it seems to work fine here, if you optimize the rest pose for ik.
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reporter
I think it seems no meaning which is better anymore. Because actually I may hope to solve the flip issue too.
But the problem is only happen, when you keep foot bone with angle. if you adjust it you can avoid it. and it only happen in range. Then you actually know, though it show more hard deform = ugry, you can easy correct it by adjusting the pole.
Current problem should happen all posing. everytime so you need to adjust Pole.
then the flip bone issue only happen with some condtion, about both case we need to adjust pole.
As for me, Current issue make MHX almost no useful as IK rig. but after all I think the flip issue need to be solved to use MHX as reliable converted rig.
I apologize Thomas to blame his enhanced rig only by himself long time. So without discuss which is worse, I decide to try to make it work. Or I think I may need to re-make rig from scratch . I may expect Thomas solve this issue, (and if he offer old rig as option, I think it is more easy to solve flip issue), but even though Thomas keep current status, I may not complain anymore, but just report as bug IK knee Pole should follow IK foot, at least current behavor is wrong enough.
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Yes of course, if we can avoid ik flipping and make the knee follow the foot that’s fine. I am not a rig expert at all so I myself can’t find the solution for that.
edit. p.s. May be the difficulty here is to keep the rig compatible with fk daz poses. I mean, my simple solution of external poles allows to don’t use “optimize pose for ik” and avoid ik flipping anyway. As I understand it, if we use “optimize pose for ik” then fk daz poses are no more compatible.
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repo owner
An option has been added for pole target parents.
The mhx rig was designed ten years ago, and when I designed it I read a bit on rigging. At the time little was written about advanced rigging for Blender, so I mainly used a book for Maya to get ideas. It was not straightforward to translate all Maya stuff into Blender, so I may very well have misunderstood something, but I think they suggested that the pole targets have parents. Anyway, with the new option the user can decide himself.
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As I understand it, and again I’m not a rig expert, it’s not that poles can’t have parents. But, since they’re a reference for the ik chain, they can’t have parents inside the ik chain. That is, if we want the ik chain to be stable and avoid flipping.
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repo owner
The parents are not inside the IK chains.
The arm chain consists of the upper arm and the forearm. The parent of the elbow PT is the same as the upper arm parent, i.e. outside the chain.
The leg chain consists of the thigh and the shin, and the ik target is the hidden ankle bone. Both the knee PT and the ankle are (great grand-)children of the foot IK, which again is outside the IK chain.
If the PT parents were inside the IK chains, Blender would surely complain about dependency loops. It does that a lot.
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repo owner
Flipping can occur anyway. E.g., if you move the ik foot vertically, the knee PT also moves vertically (child), but the knee moves both forward and upward. At some point the knee has moved past the knee PT in the horizontal direction, and the leg starts to flip.
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Yes, I see what you mean. The difference is that having the poles parented to the root they stay in place so the reference doesn’t change unless we move them on purpose, and there’s no flipping. While having the poles parented to the feet they move with the feet and may cross the knee point thus flipping. This is not a unstable ik chain per se, but requires a careful placing of the poles when we move the feet. Personally I prefer poles on the root so they move only when I want to.
That’s resolved for me. Having the choice of the poles parent seems a good solution.
p.s. Thomas if you may add shapes to the rigify face the same as mhx it would be nice. Or may be we can add this to
#451to do when you get some time.p.p.s. oops, I see it’s just done, again you’re faster to do things than I am to think about them
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I prefer the pole parented to the IK bone since it allows you to control everything from the IK bone, as shown here: https://www.youtube.com/watch?t=748&v=DZ_ocmY8xEI&feature=youtu.be
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Xin, that’s what the parent option does for the legs, and there may be flipping when you move the foot and the pole cross the knee. It doesn’t for the arms though, here the poles are parented to the shoulder instead of the hand. So this differs from the video you linked.
edit. p.s. Anyway, to be fair, it is easy enough to change the pole parent after we generate the mhx rig. So I believe anyone with a bit of experience can fit the rig to his preference. I can do it myself that I’m really basic on rigs.
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I just don’t see how having to tweak the pole every time you change the pose could be less awkward than only having to tweak it for some poses (since you have some degree of control over the pole with the IK bone when it’s parented to it). I agree with engetudouiti. It’s good that the option was restored.
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repo owner
In the last commit there are separate options for the pole target parents.
Elbow parent is one of Hand/Shoulder/Master.
Knee parent is one of Foot/Hip/Master.
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Xin, I use the poles for the knee and elbow angles so it’s just natural to me to pose them. I believe elbow to hand and knee to foot with the new options is what you want, that’s different from Engetudouiti's anyway.
Commit 2124f07 works fine here.
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reporter
Alessandro why you decide, I am different what Xin said? I said same thing.
I do not think there is any user who do not use IK Pole target with IK Foot when we adjust pose here. Of course we do so. IK Pole target and IK pose bone are set of IK rig. We know when we make IK rig. There is no one who do not understand it. So please do not take time to declare it.
At same time, Any IK human rig which I had seen, pole try to follow foot movement naturally. then with small adjustment (if you like to set pose so) you may make ideal pose for the frame, Sometimes you may move pole hard (to adjust knee direction) , when you want to set pose on the frame.
But after all from the current frame you move foot IK,, pole angle try to follow the foot movement natrually. so interpolation frame1 and frame 2 do not show strange movement.
On the other hand flip issue can avoid, and could control as limitation. though it is not perfect, and do not hope it happen, But if someone know animation which is good is too clear thing for me.
If knee do not follow Foot position but get strange rotation with foot move, you can not make smooth animation, or you may need to set key all frame for Pole between foot key1 and key2. Of course If I need to choose one of them, I prefer, knee auto follow foot even though it remain flip issue. I still not test new commit, but if the option cause flip issue, It is not good as official add on covnert rig . if one option can solve both issue, I think Thomas could solve real issue for daz convert MHX rig (FK IK). Anyway thank you Thomas return it as option. So I can choose MHX as option as same as before.
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Engetudouiti, to reply to your question “I said same thing“. It’s because what you asked for is to go back to the previous setup that’s different, 1.5.1 gets the knee pole parented to ankle.ik.L, while in 1.6.0 it’s parented to foot.ik.L as Xin suggested. Same for the arms.
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reporter
- changed status to closed
I found how to manage way, so make new topic.
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reporter
- changed status to resolved
There were already topic which related with Xin add on. then close this.
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When I test old scene MHX rig, it was stable enough for me.
But current IK chain are perfectly wrong.
If some user expect to set IK chain and pole, as current way (and think it is usall) please offer it as separate option. or I may simply hope remain old MHX way as option. not matter which is default you think.