Feature Focus: Limb IK

[Jeff Almasol]

Arm IK is now called Limb IK and can control the bend directions and stretching of legs, as well as arms. For example, pin a hand in place while moving the rest of the body or make a character's feet stick to the ground as its squats in a more realistic way.

Check out the following walkthrough video for Limb IK:

Try out Limb IK using the following example puppets!

• DraggerDude.puppet
• Chloe Full Limb IK.puppet
• LimbIKBot.puppet

Note: Limb IK and Walk behaviors on the same puppet might cause issues because both want to control the same handles. If you do have both behaviors applied, consider turning off Limb IK when animating walk cycles, and turning off Walk when doing general body animation. Limb IK should work fine in side and 3/4 views.

(Use this Beta forum thread to discuss this feature and share your feedback with the Character Animator team and other Beta users. If you encounter a bug while using this feature, let us know by posting a reply here or choosing "Report a bug" from the "Provide feedback" icon in the top-right corner of the app.)

[claytor1999]

I really like this behavior. Brings the character to life even when the settings are subtle. And for all those Canadians who were looking for a quick way to make their character skate... Limb IK --> Legs --> Pin Left and Right Heel to Puppet. Boom.

[spefferly]

This new feature is really great! I've had to get creative whenever I had characters that needed to sit down or stand up from a desk....and the pin feature is really cool.

I had only a couple minor hiccups (and maybe I'm just doing something wrong). The first issue I had was with the Reverse Leg Bend. Whenever I have that selected, the ankle doesn't seem to want to move right with the leg...it kind of flips around haha (see picture below).

Reverse Leg Bend

The other issue I had (and this one is more minor). Now that I have the Limb IK added, and have gotten rid of the pins, my character's head doesn't just move when I move my head - his hips move as well in a sort of floating delayed manner. I'm not sure if there is anything that can be done about this or not. Below are video examples of what I mean. The first being the original pinning way, and the second video is with the Limb IK added.

Those are my only two issues with it though - everything else was great! I can't wait to utilize the new features in my workflow.

[oksamurai]

Thanks for the excellent feedback!

If you can DM me the File > Export > Puppet we can take a closer look at the flipping ankle issue.

I have felt the same about your head/body moving issue - no one moves like that. If I'm understanding correctly, you would prefer to have the head move/pivot more and the hips less. If there was a control to prevent or minimize the strength of the body movement (aka the influence of the head), so it looks more like your first example but with knee bends and the other benefits of Leg IK, would that solve your issue?

[spefferly]

Thanks for the quick response! Yes...exactly. That would 100% solve my head/body moving issue. I will send you the puppet separately for the ankle issue.

Thanks again!

[DarrenFMc]

I would second that. i have already mentioned this several times, where recording the head movement only causign the body and arms to shake or shudder. It would be good to be able to lock down everything that does not need to be moved during a take.

[Jeff Almasol]

Hi @spefferly,

There's a possible fix for the ankle twisting issue in the just-posted Beta build update (3.4.0.128). Can you try it and let us know if it's working better for you now?

Thanks for reporting this issue!

[spefferly]

Thanks Jeff! Whatever you guys did - it seems to have worked!!!!

[joev871976]

Just some thoughts. 

When going through the Eliza Character, I noticed that her toes were stuck to the ground.  Is that because she has a walk function?  When I removed the tag on the toes, she went into a weird gallop walk.  The Chloe, Dragger and  the BOT Characters are stationary front Facing.  Also when jumping, Eliza's toes point down (more realistic), and the other characters stay in their position.  They seem to be rigged the same way.

[oksamurai]

Hard to say for sure with Eliza - the walk behavior has a new "pin feet to ground" checkbox (see https://community.adobe.com/t5/character-animator-beta/feature-focus-pin-feet/td-p/11301057?page=1 so that might do it, or if you're using the 3-view version of her that has a staationary view. Bottom line: I wouldn't mix Limb IK with Walk except for a stationary view where you want some stationary limb bending. Otherwise I think the two can run into conflicts because they're both looking for the same limb tags like elbows and knees.

For the toe direction when jumping, try adjusting "ankle flexibility" - higher percentages seem to make them point down more.

[oksamurai]

Update: Here is an updated version of LimbIKbot that does a bit of a hack to get more head tilting and less body tilting. Thsi was a technique I first found out about in a Digital Puppets video. It's not perfect, but hopefully it's a viable workaround for the head/body issues.

[spefferly]

This is great! Worked like a charm. So much more flexibility now with different scenarios!

[rufia74067359]

Can't seem to find the limb IK, i installed it but I only see the arm IK there on the list, what am i missing?

[oksamurai]

Did you update to the most recent version of the beta? Limb IK will only show up in the latest beta versions. If you're still seeing Arm IK, you are most likely in an older build or the public release. If you're still seeing it in the latest version (x128) please let us know.

[rufia74067359]

I didn't realize I was suppose to open CA (Beta), I opened the CA. I got it. Thanks!

[follain0101]

I am trying to use limb Ik on a quadruped character.  It's working very well for the back leg, but there are some minor problems for the arms :

- If I make the arm with arm handle tag, I can't use the option "Ground detection" and "foot pinning" for the arm. Which mean that the arm go down when the body move down.  (see the first picture)
- If I try to make the arm with "leg" handle tag  (which mean having 2 right Hip/knee/heel  and 2 left Hip/ect) ;  it's making the last handle that I have put bug (usualy the arm in this case)

The only way to have an alright Ik for the arm is to set up them with arm handle, and move them at the corect place with a dragable+ hold in place.  The only problem with this set up is that the hand rotate when the body move, it's impossible to make them keep the same rotation ; as you can see in the 2nd picture (unless I am missing a feature).

The 2 potential solutions to solve this problem could be those :
- Add an option to remove hand rotation in drag option
- Make it possible to make more than 2 legs for quadruped quaracter.  So we can use "Ground detection" and "foot pinning" for every limb  (Or maybe add "Arm pinning")

Don't mind the quality of the puppet, it's still a WIP.

[oksamurai]

I wonder if you might be better off adding a second Limb IK behavior manually to the second set of "legs" - I haven't personally tried anything like this, but theoretically it might allow for all both sets of legs to be pinned. Basically I'd probably try making two groups: FRONT LEGS and BACK LEGS, and add a Limb IK behavior to each one to see if that helps.

[follain0101]

Yes, it's work perfectly.  Thank you very much
I though for some reason Limb Ik was only a global behavior since it affect both arm and leg at the same time. Didn't think I could use multiple of them.

[gregorypezeshki]

Trying out the new limb IK in BETA with a new character. Loving the way you can get some really fluid movements, huge potential for this and Character Animator in general, been using regular version for about 6 months.

A couple issues with new limb IK:

First, whole body goes bends at knees great when using camera input, but I put a dragger on the body to move the character, bend down, etc... however while the body moves great, the top of the head sticks in place and the rest of the head layer warps, keeping it attached at the neck while also stretching out the head. Is there a fix to this or is that a bug?

Thanks for all you do!

Greg

[oksamurai]

For dragging the body around, I actually usually put it on the Head origin handle - so typically it's going to be dual tagged as head and draggable. That's our recommended placement - I think putting it on the body won't overpower the head, which is probably why you're getting the stretching look. I think some of the example characters in the first post should be set up like this.

[gregorypezeshki]

Yes! That seemed to fix the head drag issue. Thank you so much!

[Stefan_Boeker]

Limb IK is very cool! 8) 
One minor issue to improve the UX: 
When you add the "pin the wrests to scene" behaviour-option the wrests are not pinned to screne – not before you move the wrests manualy a little bit manualy. 
It whould make more sense to me if they are pinned to scene right away. 
You could save some time to every user not familiar with this new option (like me :))

[oksamurai]

Agreed, great suggestion.

[philipj25268431]

I have used this behavior successfully with simple puppets. However with a 3-view puppet, I get rigging issues on the arms for the frontal and right quarter views. Their arms are draggable but too stretchy. Only the top (left quarter) view works properly. They are all set up the same way, including the attachment style. I only have one set of legs and those work -- perhaps that's the issue. I tried reorganizing the layers, but that crashed Character Animator. 

[oksamurai]

I believe Limb IK only looks for the first instance of its tags, so if you want it to work for multiple views, you would need to add a Limb IK behavior for each view. Try adding the behavior to the Frontal and Right Quarter groups and see if it works for you then.