Component:VRIK

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Component image 

VRIK component as seen in the Scene Inspector

Introduction

Oof

— Epsilion

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.

Fields

Name	Type	Description
persistent	Bool	Determines whether or not this item will be saved to the server.
UpdateOrder	Int	Controls the order in which this component is updated.
Enabled	Bool	Controls whether or not this component is enabled.
AutoUpdate	Bool
FixTransformsEnabled	Bool	Clamps IK transforms to reasonable values and Resets IK every update.
Solver	direct IKSolverVR	The actual solver that contains most of the fields of this component.
componentInitiated	Bool
_drives	list of BoneDrive

IKSolverVR

Most of the complexity in VRIK is actually stored in the IKSolverVR type. And even this is spread across multiple types.

Fields

Name	Type	Description
IKPosition	Float3
IKPositionWeight	Float	Weight of the IK
SimulationSpace	Slot
OffsetSpace	Slot
_initiated	Bool
OnPreInitiate	UpdateDelegate
OnPostInitiate	UpdateDelegate
OnPreUpdate	UpdateDelegate
OnPostUpdate	UpdateDelegate
root	Slot
BoneReferences	direct References
defaultLocalPositions	array of Float3
defaultLocalRotations	array of FloatQ
DebugVisuals	Bool	Enables Debug visuals
PlantFeet	Bool	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.
spine	direct Spine
leftArm	direct Arm
rightArm	direct Arm
leftLeg	direct Leg
rightLeg	direct Leg
locomotion	direct Locomotion
ForwardFlipped	Bool	Swaps the feet
ForceRootHeight	Nullable`1<Float>	Foot planting height override (Negative numbers cause issues with walking)
LocomotionPositionOffset	Float3
DefaultRootPosition	Float3
DefaultRootRotation	FloatQ

References

Fields

Name	Type	Description
root	Slot
pelvis	Slot
spine	Slot
chest	Slot
neck	Slot
head	Slot
leftShoulder	Slot
leftUpperArm	Slot
leftForearm	Slot
leftHand	Slot
rightShoulder	Slot
rightUpperArm	Slot
rightForearm	Slot
rightHand	Slot
leftThigh	Slot
leftCalf	Slot
leftFoot	Slot
leftToes	Slot
rightThigh	Slot
rightCalf	Slot
rightFoot	Slot
rightToes	Slot

Spine

Fields

Name	Type	Description
Initiated	Bool
HeadTarget	Slot	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.
PelvisTarget	Slot	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.
PositionWeight	Float	Positional weight of the HeadTarget.
RotationWeight	Float	Rotational weight of the HeadTarget.
PelvisPositionWeight	Float	Positional weight of the PelvisTarget.
PelvisRotationWeight	Float	Rotational weight of the PelvisTarget.
ChestGoal	Slot	If ChestGoalWeightis greater than 0, the chest will be turned towards this slot.
ChestGoalWeight	Float	Weight of turning the chest towards the ChestGoal.
MinHeadHeight	Float	Minimum Head height allowed by the IK solver (Nonfunctional)
BodyPosStiffness	Float	How much the body will try to move with the HeadTarget.
BodyRotStiffness	Float	How much the body will try to rotate with the HeadTarget.
NeckStiffness	Float	How much the chest will rotate when the head is rotated.
RotateChestByHands	Float	How much the chest rotates based on hand movement.
ChestClampWeight	Float	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.
HeadClampWeight	Float	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.
MoveBodyBackWhenCrouching	Float	How much the body will move backwards when crouching
MaintainPelvisPosition	Float	How much the pelvis will move with the feet instead of the HeadTarget.
MaxRootAngle	Float	How much the HeadTarget must rotate for the whole body to rotate (in degrees).
IKPositionHead	Float3	The solved position for the head. Driven.
IKRotationHead	FloatQ	The solved rotation for the head. Driven.
IKPositionPelvis	Float3	The solved position for the pelvis. Driven.
IKRotationPelvis	FloatQ	The solved rotation for the pelvis. Driven.
GoalPositionChest	Float3	The solved goal position for the chest. Driven.
headHeight	Float	Head height while standing. Used for calculating MoveBodyBackWhenCrouching.
anchorRelativeToHead	FloatQ	Root rotation relative to HeadTarget.
pelvisRelativeRotation	FloatQ	Pelvis rotation relative to HeadTarget.
chestRelativeRotation	FloatQ	Chest rotation relative to HeadTarget.
chestForward	Float3	Chest Forward Vector
pelvisForward	Float3	Pelvis Forward Vector

Arm

Contains parameters for the two arms: leftArm and rightArm.

Fields

Name	Type	Description
Initiated	Bool
Target	Slot	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.
BendGoal	Slot	The arm's elbow will be bent towards this slot if BendGoalWeight > 0.
PositionWeight	Float	Positional weight of the Target.
RotationWeight	Float	Rotational weight of the Target.
ShoulderRotationMode	ShoulderRotationMode	Shoulder rotation method. Pitch/yaw is more accurate, while From/to is simpler.
ShoulderRotationWeight	Float	How much the arm's shoulder should move based on Hand position.
BendGoalWeight	Float	if greater than 0, will bend the elbow towards the BendGoal slot.
SwivelOffset	Float	Rotation offset for the arm's elbow in degrees.
WristToPalmAxis	Float3	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)
PalmToThumbAxis	Float3	Thumb Direction; local axis of the hand bone that points from the palm towards the thumb. Used for defining hand bone orientation.
ArmLengthMlp	Float	Arm Length Multiplier. Used to make the arm shorter/longer. Works by displacement of hand and forearm local position.
StretchCurve	direct SyncCurve`1<Float>	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).
IKPosition	Float3	The solved position for the arm's hand. Driven.
IKRotation	FloatQ	The solved rotation for the arm's hand. Driven.
BendGoalPosition	Float3	The solved position for the bend goal. Driven.
TwistRelaxWeight	Float	How much the forearm twists towards the wrist
TwistCrossfade	Float	Weight of the forearm twisting
TwistAngleOffset	Float	Angle offset of the forearm twisting
chestForwardAxis	Float3
chestUpAxis	Float3
forearmTwistAxis	Float3
forearmAxis	Float3
axisRelativeToUpperArm	Float3
axisRelativeToHand	Float3

ShoulderRotationMode

Values

Name	Value	Description
YawPitch	0
FromTo	1

Leg

Contains parameters for the two legs: leftLeg and rightLeg.

Fields

Name	Type	Description
Initiated	Bool
Target	Slot	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.
BendGoalPosition	Float3	The solved position for the bend goal. Driven.
BendGoal	Slot	The left knee will be bent towards this slot if BendGoalWeight > 0.
PositionWeight	Float	Positional weight of the Target.
RotationWeight	Float	Rotational weight of the Target.
BendGoalWeight	Float	if greater than 0, will bend the left knee towards the BendGoal slot.
SwivelOffset	Float	Rotation offset for the left knee in degrees.
CalfBendNormal	Float3
IKPosition	Float3	The solved position for the left foot/toe. Driven.
IKRotation	FloatQ	The solved rotation for the left foot/toe. Driven.

Locomotion

Fields

Name	Type	Description
Weight	Float
FootDistance	Float	Tries to maintain this distance between where each foot will attempt to plant themselves.
StepThreshold	Float	How far you have to move for the feet to take a step (re-plant themselves).
AngleThreshold	Float	How much you have to rotate for the feet to take a step (re-plant themselves).
ComAngleMlp	Float	Multiplier angle of the (center of mass minus the center of pressure) vector. Larger value makes the character step sooner if losing balance.
MaxVelocity	Float	Maximum magnitude of head/hand target velocity for prediction.
VelocityFactor	Float	How much the feet will use your current head/hand target velocity to predict where you're stepping.
MaxLegStretch	Float	How much your leg can stretch before it attempts to take a step. 1 means fully stretched.
RootSpeed	Float	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.
StepSpeed	Float	How fast the foot planter will move the feet to their new position when re-planting
StepHeight	direct SyncCurve`1<Float>	The height of the foot by normalized step progress (0 - 1).
HeelHeight	direct SyncCurve`1<Float>	The height offset of the heel by normalized step progress (0 - 1).
RelaxLegTwistMinAngle	Float	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.
RelaxLegTwistSpeed	Float	How fast the feet can rotate while on the ground; the speed of rotating the foot while the leg is not stepping to relax the twist rotation of the leg.
StepInterpolation	InterpolationMode	The type of interpolation the feet will use during stepping.
Offset	Float3	Offset for feet planting relative to your HMD
LeftFootOffset	Float3
RightFootOffset	Float3
OnLeftFootstep	Action	Non-Functional WorldDelegate
OnRightFootstep	Action	Non-Functional WorldDelegate
_leftFootstep	direct Footstep
_rightFootstep	direct Footstep

Footstep

Fields

Name	Type	Description
_initialized	Bool
footRelativeToRoot	FloatQ
footGroundHeight	Float

BoneDrive

Fields

Name	Type	Description
Position	field drive of Float3
Rotation	field drive of FloatQ