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Rigging Arm and IK/FK Switch Issue. please help.

jenyseok89
Explorer

Rigging Arm and IK/FK Switch Issue. please help.

jenyseok89
Explorer
Explorer

i've been trying to fix this. but i cant figure out where it went wrong.

i  made base skeleton/IK/FK and also twist joint between the humerus and radius, radius and wirst, and wirst twist joint.

constrains are connected all under the humerus joint (IK/FK part)

I also created and connected the IK/FK switch attribute with constrains/ctrl offset group.

However, when moving with the IK/FK controls, the joint movement looks strange.

I've been checked a lot and re-created it over and over again.

But I couldn't find a solution. Skinning also gets weird.

(*blue _ base  joint *yellow _ FK   *pink_ IK)

please help this :-),.,!

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Replies (6)

Kahylan
Advisor
Advisor

Hi!

 

It seems like there are quite a few things going wrong here. Your twist joints in the lower leg and lower arm are not aiming at the ankle and wrist. It seems like the Thigh joint is not connected to the switch. And I think there is probably also something going wrong with your stretching mechanics, if you have any (arm base joints seem way to long).

 

There is too much going on to tell you how to fix those issues from a few screenshots, if you could attach the scene as a zipped .ma file I could probably find the problems and tell you how to fix them.

jenyseok89
Explorer
Explorer

Kahylan! 🙂

THANKS for your attention..!i appreciate your comment!:---)

probably there is too much things went wrong and mixed up.

here is my scene file:-)

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Kahylan
Advisor
Advisor
Accepted solution

So, I took a first look at the Rig. And I decided to split up the corrections for the Leg and the Arm into two comments, since I started with the Leg and I found quite a few issues. I'll take a look at the arm later today.

 

The problems is see are the following:

 

1) The knee joint is connected to the IK/FK switch the wrong way around, so the Knee is in IK mode when the rest of the Leg is in FK mode and vise versa. This is the biggest problem, but it can also be easily fixed by just reversing the two connections on the knee switch constraint.

 

2) The visibiltiy of your controllers is also connected the wrong way around. So when your leg is in IK Mode the FK controls are visible and vise versa. Once again, just changing those connections should work out.

 

3) The pole Vector is aiming at the wrong target. The left leg Knee is aiming at the polevector control of the right leg. Just redoing the pole vector constraint for the left leg with the left leg target should fix this issue.

 

4) your twist setup doesn't really make sense. Both thigh twist joints are in the same position while the ankle joints are offset from each other, also there aren't any twist or roll calculations going on on any of them and there is no way to access them using a controller. So currently they are just additional joints that need to be painted but they don't do anything.

 

5) You dont have a foot control. I'm not sure if you just wanted to set up a direct FK control for the foot and haven't gotten around to it. But I would encourage you to extend your IK/FK Setup to the foot as well, legs are in IK mode 90% of the time so having a good IK foot setup will literally save you hours of work in animation. If you want some good foot tutorials, let me know and I will link some.

 

If you fix those things, your leg should behave more or less how you want it to. But I also have to mention, that the joints aren't oriented correctly. In the default stance all joints have more than one non-zero translation channel (they should have 1) and some of them have non zero-rotations, this will make it impossible to implement squash and stretch and it can more easily lead to gimbal lock problems during animation. So if you want your rig to be optimal, you should probably  diconnect the setups, from the controllers and each other, orient the joints correctly and redo the connections.

I know this sounds harsh. It's probably the first rig you are building. But believe me, a good rig will save you a lot of time in animation and the rig you have right now in the leg will cause you problems and headaches down the road.

 

I'll write you about the arm later.

jenyseok89
Explorer
Explorer

omg Thanks a lot! I've checked what you said and I've fixed it:-0!

and i found this foot tutorial. 

https://youtu.be/FfGfV7Lc_34

Thanks for your advice. I'll wait for next reply:----) 

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Kahylan
Advisor
Advisor
Accepted solution

Ok, so I finally got around to looking at the arm. It looks a lot cleaner than the arm, thats is good.

 

1) the wrist constraint has mixed up connections to the switch control.

 

2) same as in the leg, the visibility connections of the controls need to be changed, since FK is visible in IK mode and vise versa.

 

3) In the default pose the IK wrist control doesn't have (0,0,0) as tranlations. This doesn't affect the functionality of the rig, but it will make it harder during animation to reset to bindpose. I see you already froze tranformations at one point so freezing just the translation again in bindpose should do the trick.

 

The Tutorial you posted is one that I would have recommended to you, so following that should do the trick. If you are interested in Rigging Ant CGI has great videos in general.

 

I hope it helps!

jenyseok89
Explorer
Explorer
it helps a lot:-)
Thanks kahylan!
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