Top-level and pelvis-related nodes

• Female03MasterRoot / Female04_Anime01_SkeletonMASTER
• This is the "MasterRoot Node" of the Avatar Skeleton, under which all body bones are ultimately attached, equivalent to the overall root node of the entire character.
• When exporting animations and attachments, as long as this set of Root + skeleton naming is used correctly, actions can be reused across different avatars.

• PelvisNode
• is directly connected under MasterRoot and is also the core node of the waist/hip.
• All leg bones (lfHip/rtHip) and the spine Spine01 branch out from here, serving as the bifurcation point of the "upper and lower body".

• MasterRoot = the root of the entire body.

• PelvisNode = the "main junction" between the upper and lower body.

Nodes related to legs and feet

• lfHip / rtHip
• The left/right hip joint connects the pelvis and the thigh.

• lfThigh / rtThigh
• The left/right femur allows the leg to bend downward from the hip.

• lfCalf / rtCalf
• Left/right lower leg bone, corresponding to the bend below the knee.

• lfFoot / rtFoot
• Left/right sole, controls the rotation and tilt of the foot on the ground.

• lfToes / rtToes
• Rough bending control of left/right toes for more natural movements such as walking and tiptoeing.

• Spine01 / Spine02 / Spine03 / Spine04
• Above the PelvisNode are the spinal bones in sequence, controlling the bending and twisting of the waist, chest, and upper back.
• When doing forward and backward bending, left and right swaying, and rotation of the body, these segments are mainly used to control the posture and center of gravity.

• Neck01 / Neck02 / Neck03 / Neck04
• The neck bones, which connect the spine and the head, are responsible for the smooth transition of the head's upward and downward movements, as well as left and right rotations.

• Head
• The real "skull", which controls the overall orientation of the head, serves as the attachment reference point for many accessories (hair, hats, headphones, etc.).

• zhead
• The "procedural gaze" system for IMVU enables avatars to look in a specific direction.
• Official Note: Ordinary creators generally do not need to directly use this skeleton for animation or attachments, as it is mainly for internal system use.

• lfClavicle / rtClavicle
• The left and right clavicles connect the upper part of the spine to the shoulders.
• Used for fine-tuning shoulder elevation/retraction, controlling upper body posture to be more natural.

• lfShoulder / rtShoulder
• The left and right shoulder joints, which connect the collarbone and the upper arm, are the main bones for large-scale arm movement.

• lfbicep / rtBicep (sometimes written as lfBicep / rtBicep)
• Left and right upper arm bones, in conjunction with Elbow, control arm bending. The specific naming may vary slightly in case in different skeleton versions, but the function remains the same

• lfElbow / rtElbow
• The left and right elbow joints mainly control the bending angle of the arms.

• lfWrist / rtWrist
• Rotate and flex the entire hand relative to the forearm at the left and right wrists.

• lfHand / rtHand
• Left and right palms, the master control node, with all finger bones hanging beneath it.

• lfmetaCarpal01–05 / rtmetaCarpal01–05
• corresponds to the metacarpal bones from the thumb to the little finger.

• lfThumb01d / lfThumb02 / lfThumb03 / rtThumb01 / rtThumb02 / rtThumb03
• The three phalanges of the left/right thumb are used for actions such as making a fist and pinching objects.

• lfFingerIndex01/02/03、lfFingerMiddle01/02/03、lfFingerRing01/02/03、lfFingerPinky01/02/03
• The three phalanges of the index finger, middle finger, ring finger, and little finger.
• The same applies to the right hand, such as rtFingerIndex01/02/03, etc.

xTipBones and other "technical bones"

• xTipBonexx (such as xTipBone33, xTipBone86, etc.)
• These xTip bones are essentially end auxiliary bones used to work with the old Physique/weight system to ensure that the skinning tool correctly handles end weights.
• Official Note: Creators usually do not need to directly animate these bones or attach accessories to them. They can be understood as "technical points that can be left untouched".

• Various AttachmentRoot / AttachmentNode
• When creating an accessory, the AttachmentRoot and AttachmentNode bones are used as the accessory's own skeletal root and attachment point.
• AttachmentNode is usually bound/aligned to a specific bone (such as Head, lfHand, etc.) in the Avatar Skeleton, thereby determining the position where the attachment appears on the character.

Rules and Points to Note for the Skeleton Structure

• Hierarchical Structure Rules
• The Avatar Skeleton must have a MasterRoot (such as Female03MasterRoot), to which all bones ultimately connect back.
• The bones have a parent-child relationship: Pelvis → Spine → Neck → Head; Pelvis → Hip → Thigh → Calf → Foot → Toes, etc. The strict hierarchy ensures that there will be no errors during animation export and import.

• The Importance of Naming
• IMVU matches animations and attachments by bone names. If your animations use the official bone names, they can be reused on different avatars; conversely, if the names are changed or the structure is disrupted, the animations cannot be applied correctly.
• Attachment points (such as Head, lfHand, rtFoot, etc.) also fully rely on standard bone names. Renaming them arbitrarily will cause attachment positions to be incorrect or not display at all.