The VRIK component is used to configure Inverse Kinematics on an avatar, for posing joints based on the position of IK Targets such as a VR HMD, hand tracking, or Vive Trackers
This component is automatically configured when importing a mesh with a detectable humanoid rig, and generally should not be modified unless you know what you are doing.
Documentation on this component may take some time, as it is very complex, and not commonly used. The basis for this component seems to be the VRIK solver developed by Final IK.
Usage
All weight values are 1-0, excluding clamps which are inverted 0-1.
You can overdrive some of them with interesting results.
When enabled, feet positions will be prioritized over anything else including HeadTarget. (Causes issues with walking) If true, will keep the toes planted even if the HeadTarget is out of reach, so this can cause the camera to exit the head if it is too high for the model to reach.
Typically the position and rotation of the HMD tracker. Note: on my own avatar, this is set to null. It's possible that this value isn't used, and instead the Head slot of the User is used.
Typically the position and rotation of the hip tracker. Note: on my own avatar, this is set to null. It's possible that this value isn't used, and instead the hip tracker slot of the User is used.
How much the chest can rotate relative to the head with 0 being full movement and 1 being no movement. A value of 0.5 allows 90 degrees of rotation for the chest relative to the head. A value of 0 allows 180 degrees and a value of 1 means the chest will be locked relative to the head.
How much the head can rotate relative to the HeadTarget with 0 being full movement and 1 being no movement. A value of 0.5 allows 90 degrees of rotation for the head relative to the HeadTarget. A value of 0 allows 180 degrees and a value of 1 means head rotation will be locked to the HeadTarget.
The target for the arm's hand. Note: on my own avatar, this is set to null. It's possible that this value isn't used, and instead the appropriate Hand slot of the User is used.
Palm Direction; local axis of the hand bone that points from the wrist towards the palm. Used for defining hand bone orientation. (Higher values on the Y axis increase the amount the arms move with your controllers)
Unsupported. Would evaluate stretching of the arm by target distance relative to arm length. Value at time 1 represents stretching amount at the point where distance to the target is equal to arm length. Value at time 2 represents stretching amount at the point where distance to the target is double the arm length. Value represents the amount of stretching. Linear stretching would be achieved with a linear curve going up by 45 degrees. Increase the range of stretching by moving the last key up and right at the same amount. Smoothing in the curve can help reduce elbow snapping (start stretching the arm slightly before target distance reaches arm length).
The target for the left foot/toe. This isn't the left foot tracker itself, but a child Slot parented to it so you could adjust its position/rotation to match the orientation of the foot/toe bone. If LeftToes is assigned, the solver will match the left toe bone to this target. If no LeftToes is assigned, LeftFoot will be used instead. Note: on my own avatar, this is set to null. It's possible that this value isn't used, and instead the left foot slot of the User is used.
How fast the pelvis and legs will move to catch up to the HMD; the speed of lerping the root of the character towards the horizontal mid-point of the footsteps.
How much your HMD has to rotate before your feet begin to rotate towards your HMD without stepping; rotates the foot while the leg is not stepping to relax the twist rotation of the leg if ideal rotation is past this angle.
