VR arms becomes much shorter in new IK, causing extreme arm pull
Nimbkoll
The IK beta introduced a lot more arm pull (where my VR arms is a lot shorter than my IRL arms) for me, on every avatar I have tested so far.
This issue might be related to other users' report where their trackers are under the floor, and their arm length shortened. (I also experienced trackers going under the floor.)
EDIT:
After discussing with Kung on Discord. It is concluded that:
- The arm pull is much less severe while T-posing (around 1 inch) than with arms extended forward. (around 2~3 inches)
- It might be worth increasing the back and forth range of motion on the shoulders to combat arm pull.
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Shiro K
Wow! Build 1171 has fixed the issue for me. It feels much better now.
F
Finnish-Puppy
yeah i really dislike this change i hope they change this back to how it was but also im having this issue with my legs my feet feel way more under my feet than it should be
Shiro K
I have the same issue on any of my avatars with FBT 6point tracking. The arm of my avatar starts to bend, when my real arm is already bent 45° degrees. The arms feels right, when I increase my size by 13cm (5 inches). But then, my feets are under the floor. I use Vive Controllers by the way.
xantoz・ザントス
Personally I find the biggest difference here between Legacy IK and IK 2.0 is the presence/absence of torso leaning. I made a related canny here:
By the way, I never felt like the shoulder bones moved a lot in Legacy IK, anyway. At least this seems the case for 6 point regardless of controller, and for 3/4-point when using Index controllers. I only ever noticed the shoulder bones moving significantly in 3/4-point tracking when using Vive wands.
pager
While the big issue, the scaling bug, has been fixed, I still think the scaling ratio is a bit too small when in arm scaling mode.
My arms in vr max out just before my arms irl do, and the hand consistently detaches at the end of my reach. I've gotten a few other people to confirm that this is still the case in the last couple nights.
With scaling by height now an option, imo there's less reason to err on the too small side since there's a good option there, and there's no way aside from user height/playspace tweaks to make it larger.
It's still a super subjective thing so I'm actually really curious what's normal here (partially for imscale too).
pager
Two notes
- I think there's a world scale bug right now making the arms even shorter than they should be
- If user height is adjusted so that the viewport lines up with your headset it's significantly better, but still a smidge too short imo. Probably don't want to limit it to just my feedback here, everybody is slightly different and finding a happy medium on arm length (aka world scale) is probably hard.
Namekotuki
As others have commented, I think IK 2.0 is strongly affected by the lack of movement of the shoulder bones.
In the previous IK, when I lowered my arms, my shoulders also went down, but in 2.0, when I raise my arms, my shoulders go up, but when I lower them, they don't go below the T-pose angle. This has also led to the need to lower the shoulders in T-pose.
When I put my arms out in front of me, the starting point of the movement is also different from my actual body, which is the reason why I feel my arms are not long enough.
I would like the shoulder bones to be flexible in all directions, not just upward.
emperorofmars
As far as i see it, the issue is due to the shoulders not moveing.
If i completely pull my shoulders inwards and only rotate the joint, the arms length seem fine. The moment i move them, not just rotate, my real hands reach way beyond my virtual hands. The vrchat ik 2.0 does not account for the shoulder joint moving.
Sadly, this makes the beta feel terrible. The shoulders need to move and the hands need to always be where they are in real life. I need to set my user real height about 15-25cm higher (from 175cm to 190 or 195) to make this not a pain.
I also tried to make the arms of my avatar long enough, which looks rather comical and way beyond any reasonable human proportions, and it still doesn't feel good ingame. Reaching forward, they still lock up way before my real hands, even with a much increased shoulder bone. And while holding the arms down, they are strongly bent ingame when thay are fully locked out irl.
Moving the arms to the side, my right arm locks out before the left one, moving them forward, the left one locks out first. My irl arms are symmetric, there was co controller drift or anything.
Rotating irl doesn't change behaviour, pressing the controllers and trackers against my headset and rotating irl doesn't show any wobble.
Disabling fbt completely, the arm length issue and assymetric bending is still present.
Kung
emperorofmars: Were you able to determine if you could rotate 180 degrees IRL (or some other orientation) to see if your opposite elbow would look first? This looks identical to an issue with HMD and controller offset (though you already reported that holding controllers against your HMD seemed rigidly locked when you spun around, the effect there would have been subtle). Can you find any orientation in 360 degrees if IRL rotation where the effect reverses?
emperorofmars
Kung: I tried many different directions and i also tried my second pair of index controllers. The IK behaviour is consistent across all of that. I screenrecorded the steamvr mirror window. I can't paste it in here, is it ok if i dm it on discord?
Kung
emperorofmars: Thanks for doing the additional testing. I have my DMs turned off but you can embed it in the ik-2-beta channel and then copy the link to the embedded file here.
emperorofmars
Kung: sorry it took me a while, here is the video: https://discord.com/channels/189511567539306508/946881839400882196/951172604071403560
Franada
What about, let say, some kind of gizmo that show the max angle a bone can rotate and can be edited. Sound like a good idea. Just saying. 🤝
Franada
Shoulder should rotate forward to fix the reach issue. I understand the decrease of the down to help longer shoulder bone but over extension with IK chain never look good.
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