ik/fk swap + stretchy bones + twist bones = huh?

[eek]

OK!

So the key is you driving a deformer chain, to do what you want, in your case its IK/FK and stretch.

Twist is a system that rides your deformer chain, only because its riding or being driven by the others IK,FK chains.

[zacleck]

I kind of theorized a solution for myself, but since I haven't put it into practice yet I wanted to make sure I understood you correctly.

The twist bones go on the deformer chain and the stretch goes on the ik chain, right? I wasn't planning on adding the stretch to the fk system because it seems to me that if the character's arm is stretching then the elbow should be bending (at least for a typical character). Have you found there to be an advantage with adding an fk stretch or is it just a preference thing?

I appreciate the responce, by the way

zac.

[PEN]

IK / FK Arm
http://www.paulneale.com/tutorials/IKFKarm/IKFKarmSetup.html

Twist Bones
http://www.paulneale.com/tutorials/twistBones/twistBones.html

Stretchy Bones thanks to Mathieson Facer
http://facerfx.com/tutorials/StretchyTwistBones/index.html

That might get you what you are looking for.

[eek]

I kind of theorized a solution for myself, but since I haven't put it into practice yet I wanted to make sure I understood you correctly.

The twist bones go on the deformer chain and the stretch goes on the ik chain, right? I wasn't planning on adding the stretch to the fk system because it seems to me that if the character's arm is stretching then the elbow should be bending (at least for a typical character). Have you found there to be an advantage with adding an fk stretch or is it just a preference thing?

I appreciate the responce, by the way

zac.

The stretch goes on the IK/FK chains yes - well you need it on both to snap them together in sync right?

[zacleck]

you guys are awesome, thanks for the help.

The stretch goes on the IK/FK chains yes - well you need it on both to snap them together in sync right?

well I was thinking any time the arms would be stretching I could handle it all in ik, and when I needed to switch to fk, the ik would be in a pose that wasn't stretched.

Also wondering, is there a quick setup to key the stretchiness on and off or is it more complicated? For the project I'm rigging for I definitely do not have time to incorporate it now, but I'm still interested in learning how to for later rigs that I'm sure to build.

zac

[zacleck]

IK / FK Arm
http://www.paulneale.com/tutorials/IKFKarm/IKFKarmSetup.html

Twist Bones
http://www.paulneale.com/tutorials/twistBones/twistBones.html

Stretchy Bones thanks to Mathieson Facer
http://facerfx.com/tutorials/StretchyTwistBones/index.html

That might get you what you are looking for.


Okay, so I set up my arms using the three tutorials above and all worked well except that the left side, the side where I mirrored my bones over, is flipping the twist bones when the elbow is rotated 90 degrees.

I often find weird orientation issues with my mirrored bones and I was wondering if this was potentially the issue and if anyone else has had issues with mirroring bones in max.

[Duncs]

Chances are it's not the bones causing your problem - if you mirrored them using the mirror utlility in the bonetools rollout then one of their axes will have been rotated instead of mirrored into place.

This means that if you then mirror your control objects using the standard max mirror tool you will be introducing an inconsistency between their orientation and the mirrored bones.

So, instead of mirroring your control object, make a copy and align it to your mirrored bone in orientation and position.

Not the easiest thing to explain quickly - PEN's rigging DVDs explain this process very well - available here (https://www.cg-academy.net/es_catalog/index.php?cPath=22_40&osCsid=eunbrc9i2a6p4so6rueu4isqkm7q47rd)

[zacleck]

So, instead of mirroring your control object, make a copy and align it to your mirrored bone in orientation and position.



I make it a habit not to mirror anything besides bones, so the controller itself isn't the issue.

I was looking at it again today and it doesn't seem to flip the bones unless there's a keyframe on the controller. I was playing around with the point helpers for the forearm twist stretch bones and it seems they're not staying aligned to the arm. at 90 degrees they rotate in the x axis, even though the x axis is wired into the exposed transform. It's happening to both arms but i didn't notice the other because the mesh wasn't twisting up like the mirrored side was.

It's gotta be because of the exposed transform and the twist stretch set up. weird weird situation, hopefully someone out there can help me figure it out.

[zacleck]

played around with the axis order of the exposed transform and it fixed it, so nevermind

zac

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.