VRChat IK 2.0

This is motivated by @Kung's request in this post: https://feedback.vrchat.com/vrchat-ik-20/p/in-lock-both-mode-spine-scrunching-pathologically-overbends-the-neck In general, it seems that there's a bunch of cases where one-solution-fits-all would leave at least some people disappointed with the default behaviour of IK and no option to change it outside of [redacted]. As such, it seems sensible to provide more in-depth IK options that would allow users to fine-tune it for their own preferences and avatars. Naturally, it won't hurt to clearly mark these in-depth options as "advanced" and maybe collapsed by default so that average users won't be spooked by a huge array of variety - that and defaults that work well for most users will likely be sufficiently user-friendly. One important aspect here is in-game availability. Given that these options concern IK, having to edit a config file (and maybe even restart the game) just to see their effect would be incredibly bad for usability. On top of that, this same approach can be used during open beta to let users try out different approaches and solutions and gather feedback on what works and what doesn't. Options that produce split feedback would indicate that keeping it as an actual option for release might be beneficial, as people have different preferences on that specific thing. Additional discussions and ideas on this topic can be found in comments here: https://feedback.vrchat.com/vrchat-ik-20/p/chest-trackers

The head on desktop is limited to -35-45~ degrees of up/down motion from a third person view. The BetaIK does not take this limit into account, and will push the entire body forward/back once you've looked past that outside limit. Clip explains it better: https://cdn.discordapp.com/attachments/946881839400882196/969455978024173648/VRChat_2JLQUSBUdr.mp4 I used the world Full Body Calibrate for the clip, as it has a third person camera available for desktop: https://vrchat.com/home/world/wrld_a5e9ec13-36b1-4e63-ae0c-dab9023401f9

This is a bit of a specific case, but I have some avatars that I actually don't want the spine to bend on. My problem comes when I limit the spine rotation in Unity in the avatar config, my hip is always rotating with my tracker, However on certain avatars I don't want that to be the case due to their body shape. When I limit the spine rotation, the head desyncs from my real head in Lock Head, Lock hip and lock both mode and the entire spine bends downwards because the hip tracker rotation is always forced to rotate the hip no matter what. I feel like if there's a rotation limit on the avatar rig settings, it should possibly keep your head in place and make the spine not rotate on the up/down axis, and decoupling your hip tracker rotation in this case so your spine stays straight, I know it's not really physically accurate but it can be a stylistic choice for avatars with strange body shapes. Attached below are the rig muscle settings in Unity combined with how it looks like in-game. I'm doing the exact same pose here IRL in both screenshots. I wonder if this could be a setting or something?

If you're using full body tracking and then proceed to turn off all your trackers, your avatar of course falls back to three-point tracking. However, for locomotion animations to start working again (e.g. those provided by Gogo Loco or Gorone System), the avatar has to be reloaded. This in itself works fine, however the issue I am running into is that this avatar reload only seems to happen after some form of user interaction: say opening the quick menu on either controller. I might be remembering wrong, but I believe that before IK 2.0 this either used to be automatic, or that no reload used to be required for locomotion animations to start working again after turning off your trackers. I understand that with IK 2.0 the reload is necessary, but it would be great if this reload were to happen automatically. My use case for this is that I develop an external tool that turns off motion trackers and falls back to controling locomotion animations over OSC when users fall asleep. Because users who are asleep cannot provide the necessary user input to trigger the avatar reload, there is no way for them to transition between FBT and locomotion animations. Alternatively, getting the ability to trigger an avatar reload over OSC would be a possible workaround.

TLDR: Vrchat elbow behavior is still incorrect, With 6-point tracking. I have used streaming motion-capture software that is more accurate. The information below best explains this. Check screenshots. The following is a screenshot captured from my motion capture software that I use for streaming. This software's IK system Best reflects my physical body's actual pose in physical reality. Notice where my elbows are. Notice how my forearms are parallel with my virtual body. This is a one-to-one with reality. This was captured using a six-point tracking system. The Avatar reflected here is a vrm conversion of Vrchat Avatar. The Armature of the Avatar is no different than the one that is being used in vrchat. It was converted to using {UniVRM} https://drive.google.com/file/d/1NWHFrszOCzLsI3X6GSy3IDcuHuBQJf-t/view?usp=sharing The following is a screenshot captured from vrchat. I'm using the exact same trackers (6 point) Again the Armature with the avatar is no different than the one in the previous screenshot. Notice where my elbows are and how they are not in the correct position. My forearms are at an angle and not parallel with my virtual body. My physical body is posed is the exact same as in the previous screenshot, above but VRChat doesn't reflect this. The only way I can explain why there's a difference between these two is perhaps in the IK systems that the motion capture software uses in relation to the one that vrchat is currently using in the most recent ik beta. I'd really like to see behavior like this change. This is only a small example of the desync I have experienced between physical bodies and virtual ones. There's a similar effect with knees. I don't have the time to capture every single pose and every single desync that occurs. But if I notice anything specific I can post another canny post or attach it to this one https://drive.google.com/file/d/1NSaJEzdqrB-kP8Wp3CjCqvZLI5IdOcgP/view?usp=sharing I updated the original post to be more clear.

I'm not exactly sure what caused this but recently after my Quest 3 updated (V79.1031) my head IK has been doing these jerky movements. This occurs on 3pt tracking and 6pt tracking with Hips and Head spine mode locked. In the GIF I'm only looking straight up and straight down and you can see the extra rotations. Although when I move really slow I can do a normal nod This movement happens to every avatar I try on. Has this happened to anyone else?

Stop locking avatars in place when players walk through walls or high furniture by walking around in their playspace. It's unnecesary, doesn't help with immersion, is annoying, causes confusion, and/or gives cursed results. If you want to add some optional thing for world creators so players can't look through walls and cheat in games n such: be my guest, but this current behavior doesn't work this way.

Sometimes when booting up VRChat, my hands will not be aligned perfectly with my view. This causes full body tracking calibration to look worse, as if my hands are slightly to the right of me. I've noticed its always offset from my view ball (avatar descriptor) where it should be, and restarting sometimes fixes the issue. Perhaps there is something going wrong when first initializing VRC that causes it to be confused where my head actually is? EDIT: The offset issue is happening between loading new instances too. But not for my head, just the trackers.

Instead of having an arm ratio, why not let users set both their height and arm span?

See attached video. When I lock in in 11 point tracking using Lock All mode. and the hip tracker is on the side of my hip, the spine leans to one side. This is 100% repeatable across multiple different types of avatars whether they are my own or from other creators and in different body types. The issue is not present when the hip tracker is centered at the front of my body.