Arm Rig Headache

#1
Trying to set up, what I think is a simple arm set up.

First, what is the proper way to construct a hand and finger set up at the end of the arm. I can't seem to do that without having finger bones all over the place and then have to manually try to straighten them all out. Not sure where the fingers should be "sprouting" from.

Secondly, I have a simple IK set up on the arm and I would also like to add a wrist control to rotate the wrist. Each time I try to put a parent constraint on the same bone as the IK is on, the bones wig out or Cheetah freezes. I assumed it might be a priority problem, but that didn't seem to fix it.

I've attached the file here with the problem. The Circle is what I'm trying to parent to use to rotate the wrist.

I appreciate any enlightenment!
Bob
 

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#2
The only luck I have had doing what you are trying to do is use an orientation constraint on the same target as the IK. This does work, but you have to make sure your bones orientation match the world coordinates or you will end up with backward rotations.

I will upload a demo file when I get the chance.
 
#3
You can now fully control the hand with the circle you had.

The two main issues were bone orientations and IK Priority. I bumped the IK Priority down to 9 and left the orientation at 10. The bone orientation I did by hand. I rotated the orientation of all bones 180* on the Y axis to match the world better. Again, that is the only way I can get the orientation constraint to work right.

There might be a better way, but I have not found it yet.
 

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#6
Yeah, the other problem I had was how to make the fingers. I seem to keep getting extra joints. Not sure where I should start from. And, I can't get them to just come out straight no matter which view I use. They shoot out all over the pace and I have to manually adjust each joint of each finger.
 

ZooHead

Well-known member
#7
I've done a lot of testing with a set up for shoulder control and scraped it because it never worked 100%.
Same with this one. My thought is the best controller is the Transform Tool, so just select the "wrist/ankle" bone.
It's not worth it if it 's so hard to get working each time.
 
#8
OK, Does this seem odd, though< right? I'd swear that's the way to set that up, but it doesn't seem to work in Cheetah.

Also, did you try making fingers at the end of the arm?
 
#9
Another odd thing: Joint 6 won;t rotate on it's own. All the other ones seem to but not that one.

This is just testing, so I know things are far from perfect here.
 
#11
So, after doing that, I can continue to make the rest of the joints on each finger/toe? It seems when I do that, the continuing toes shoot out all over. They don't stay in line with the rest if the toe. And I can't use Splint Joint, becasue each single joint is basically a tip joint.
 

ZooHead

Well-known member
#12
If you do it this way it will work.

I guess this is one reason why I use the Joint Object instead of the Joint Tool.
All my bones start out straight with zero rotation except the root connectors.
 
#13
Yes, I did do a quick test and you can split these.

It would be nice if holding shift while setting a new bone kept them in a line.

I may play around with the Joint Object.

Thanks for your help!
 

ZooHead

Well-known member
#15
Random tip, rotate don't slide, except for the root joints.
That's the ones connected to the hip/shoulder/root connector bone.
 
#18
That sounds strange to me. Can you make a short video or Gif about it? - never happened to me. Starting to guess snapping will cause it - but it´s not during joint layout.

Cheers
Frank
Try adding bones to the ends of the fingers. I used top view, clicked the last bone, then clicked in front with the joint tool and got an up pointing bone. This may be normal behvior since the bones aren't stright, but from top view I'm not sure why it woul not stay at least level with the bones it's coming from.
 

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ZooHead

Well-known member
#19
That sounds strange to me. Can you make a short video or Gif about it? - never happened to me. Starting to guess snapping will cause it - but it´s not during joint layout.

Cheers
Frank
I think the end of his bone is is compound rotated, and not in line with the bone.
So any additional joints are also akimbo.
 
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