VRChat IK 2.0

The way to reproduce this that we found was to recline on your back at about 45 degree angle (gaming chair style) and simply move the head a bit. What you'll observe is the hip swinging wildly forward and back, as if moving between the tracked position and the animated position of crouch animation. While in head lock mode hip drift is inevitable in some poses, I'd expect the hip to at least stay constrained to the line going through head and hip trackers (i.e. it drifts down, away from head), instead of just going to completely random positions unrelated to hip tracker position.

I've noticed for a lot of users on the test world that their feet on their avatars was clipping through the bottom of the world. May be worth checking to make sure everything is alright (No playspace movers, heights accurate, happened across multiple avatars)

I have noticed that the when using "lock head" mode in the new IK beta that the spine of some avatars will twist erratically. I was told that this is due to some avatars hip root bone not being oriented up correctly as the new IK in lock head mode does not account for non zero hip rotation. While it is good practice to have the hip bone oriented properly (as the SDK has been warning us about for years) this is the first instance of it affecting avatars in a tangible way. This will break years worth of content if not accounted for, some of which reuploading or remaking is not feasible, there are tens of thousands of avatars which have an inverted pelvis already in vrchat. I know my current base that I sell suffers from this and I do plan to make a patch to address this issue regardless, but it will not fix the 2 years worth of content people using my base have already made, it would also break existing animations that use the tail. I know that the rexorium base suffers from this issue as well as other popular base models. Another issue that this change doesn't account for is non blender users. Maya for example has a different way of handling bone orientation than blender does and if a model needs to pass through both modeling suites a hip error like this can occur even if its accounted for in one of the programs. While it could be a slight performance or accuracy hit to check for hip orientation on avatar load I feel it is a worthy sacrifice in the name of preservation.

※ The original Japanese text is shown below the English text.（英文の下に日本語の原文を載せています） Please publish clearly the details about avatars adapted to VRC's IK from the official document. (with pictures). Currently, the avatar's bone structure is mainly a matter of user-to-user information exchange, and is still in the realm of speculation. In addition, there is no end to the number of accidents that occur when FBX exported from Blender are opened in Unity, such as Armature being scaled 100 times, or being rotated -90° on the X axis due to differences in the software's rotation axis. When I recently reposted the FBX output instructions on Twitter, lots of people responded. https://twitter.com/0ne_chan/status/1525653071497289728 That's how many people don't know about avatar standards. With Blender, it's just a matter of adding an addon, but there were a lot of people who couldn't get to that information, and I was one of them. I would like to know the criteria for a suitable avatar for VRChat, such as, "How much angle is acceptable for the spine bones?" It would be a great help to the creators of avatars, costumes and accessories, which have increased a lot thanks to VRChat, if this information was made public by the official document. VRCのIKに合わせたアバターについての詳細を公式から明確に公表してほしいです。（画像付きで） 現在、アバターのボーン構造についてはユーザー同士での情報交換がメインとなっており、憶測の域を出ません。 また、BlenderからエクスポートしたFBXをUnityで開くと、Armatureのスケールが100倍になっていたり、ソフトの回転軸の違いからX軸で-90°回転していたり、という事故が後を絶ちません。 先日FBXの出力方法をTwitterで再掲したところ、沢山の人が反応をしてくれました。 https://twitter.com/0ne_chan/status/1525653071497289728 それくらい、アバターの基準について知らない人が多いのです。 BlenderならAddonを入れれば済む話なのですが、その情報に辿り着けない人が沢山居て、私もその中の一人でした。 「背骨のボーンはどれくらいの角度までなら許容範囲なのか」ということなど、VRChatに適したアバターの基準を知りたいです。 これらの情報が公式から公表されれば、VRChatのおかげで沢山増えたアバターや衣装やアクセサリーの制作者の方々は非常に助かると思われます。

This is mostly personal preference of the wearer, not the maker, so being able to always slide around (or always walk around) would be really nice to have here

~Kung Remainder Canny~ Discussed this a bit with Kung and it was realized that calibration saving can still function as intended when swapping between height and arm span measurement and that toggling between the two methods should no longer force a recalibrate, so setting this canny up as a remainder to revisit and correct that.

With the new IK2 system, the Auto Footstep is resetting the positions of the feet when locomotion stops, rather than continuing the procedural animation from the foots current position. This causes the feet to slowly slide from your idle pose into the tpose position when locomotion stops. This will happen to all avatars with their legs in a non default position at idle. https://streamable.com/pvdi2q

Avatar will have foot IK target previous still position for a second once you stop moving. Beta IK does not have this issue. Desktop and VR (no fbt). (fixed on desktop once swapped to Beta IK from VR) Edited canny to reflect new findings. nakos

Please save calibration between avatars so we dont need to recalibrate every time when we switch avatars.

The new beta version of the IK 2.0 introduced shoulder tracking when using elbow trackers on your upper arms However, using elbow trackers on your forearms would break your avatar's shoulders. While this wouldn't be a problem for people using Vive or Tundra trackers, people using SlimeVR would suffer greatly from this. SlimeVR (a cheap FBT solution using IMUs) estimates your elbows positions from your controllers and a single tracker on your forearm. The tracker must be on the user's forearm (I would know, I developed it :p). This would effectively make SlimeVR elbow tracking unusable in VRChat. A simple solution for this would be to add a toggle somewhere to switch between "Elbows-only" and "Elbows and Shoulders" tracking mode.