# Ep.15 — Skin Bones Node Reference (`Skin_*`)

This document shares the naming guidelines for `Skin_*` bones generated by BipedPlus as default values.
It reflects the naming conventions OtakuSolutions follows for 3dsMax rigging.

If your team does not have internal rigging naming guidelines, feel free to use this document as a reference.
When customizing the rig, maintaining these node names and structural conventions ensures full compatibility.

BipedPlus uses a **dual-bone structure** for certain joints, separating the main bone from segment bones (`_Seg`).
This design enables joint stretching and prevents scale errors.


| | |
|---|---|
| Pattern | `Skin_*` |
| Left + Center nodes | **85** |
| Right nodes (mirror) | 63 |
| Total nodes | **148** |


### Skinning Structure Design

| Role | Description |
|------|-------------|
| Main bone (`is_skinned=X`) | Primary axis/rotation for joint motion. No skinning needed. |
| `_Seg` bone (`is_skinned=O`) | Child of main bone; handles per-segment mesh deformation. |
| `_Twist` bone (`is_skinned=O`) | Distributes twist rotation along the limb. |
| `_Cor` bone (`is_skinned=O`) | Corrective bone for bilateral symmetry correction. |
| Bones with no Seg/Twist (`is_skinned=O`) | Skinned directly to main bone (e.g., Finger, Hand, Foot). |
| `Nub` bone (`is_skinned=X`) | Chain endpoint marker. No skinning needed. |

### Field Descriptions

| Field | Description |
|-------|-------------|
| `direction` | left / center |
| `is_skinned` | Whether the bone receives skin weights (O = yes, X = no) |
| `parent` | Parent node (`{LAST}` = last-numbered bone in the chain) |
| `part` | Rig module part ID |


### Node List (85 — Left + Center)

| node | part | direction | parent | is_skinned |
| --- | --- | --- | --- | --- |
| Skin_Com | spine | center | Root | O |
| Skin_Pelvis | spine | center | Root | X |
| Skin_Spine | spine | center | Skin_Pelvis | X |
| Skin_Spine1 | spine | center | Skin_Spine | X |
| Skin_Spine2 | spine | center | Skin_Spine1 | X |
| Skin_Spine3 | spine | center | Skin_Spine2 | X |
| Skin_Spine4 | spine | center | Skin_Spine3 | X |
| Skin_Pelvis_Seg | spine | center | Skin_Pelvis | O |
| Skin_Spine1_Seg | spine | center | Skin_Spine1 | O |
| Skin_Spine2_Seg | spine | center | Skin_Spine2 | O |
| Skin_Spine3_Seg | spine | center | Skin_Spine3 | O |
| Skin_Spine4_Seg | spine | center | Skin_Spine4 | O |
| Skin_Spine_Seg | spine | center | Skin_Spine | O |
| Skin_Head | neck-head | center | Skin_Neck | X |
| Skin_Neck | neck-head | center | Skin_Spine{LAST} | X |
| Skin_HeadNub | neck-head | center | Skin_Head | X |
| Skin_Head_Seg | neck-head | center | Skin_Head | O |
| Skin_Neck_Seg | neck-head | center | Skin_Neck | O |
| Skin_Neck_Twist | neck-head | center | Skin_Neck | O |
| Skin_L_Clavicle | arm | left | Skin_Spine{LAST} | O |
| Skin_L_ForeArm | arm | left | Skin_L_UpperArm | X |
| Skin_L_Hand | arm | left | Skin_L_ForeArm | O |
| Skin_L_UpperArm | arm | left | Skin_L_Clavicle | X |
| Skin_L_ForeArm_Seg1 | arm | left | Skin_L_ForeArm | O |
| Skin_L_ForeArm_Seg2 | arm | left | Skin_L_ForeArm | O |
| Skin_L_ForeArm_Seg3 | arm | left | Skin_L_ForeArm | O |
| Skin_L_ForeArm_Seg4 | arm | left | Skin_L_ForeArm | O |
| Skin_L_ForeArm_Seg5 | arm | left | Skin_L_ForeArm | O |
| Skin_L_UpperArm_Seg1 | arm | left | Skin_L_UpperArm | O |
| Skin_L_UpperArm_Seg2 | arm | left | Skin_L_UpperArm | O |
| Skin_L_UpperArm_Seg3 | arm | left | Skin_L_UpperArm | O |
| Skin_L_UpperArm_Seg4 | arm | left | Skin_L_UpperArm | O |
| Skin_L_UpperArm_Seg5 | arm | left | Skin_L_UpperArm | O |
| Skin_L_Finger0 | finger0 | left | Skin_L_Hand | O |
| Skin_L_Finger01 | finger0 | left | Skin_L_Finger0 | O |
| Skin_L_Finger02 | finger0 | left | Skin_L_Finger01 | O |
| Skin_L_Finger1 | finger1 | left | Skin_L_Hand | O |
| Skin_L_Finger11 | finger1 | left | Skin_L_Finger1 | O |
| Skin_L_Finger12 | finger1 | left | Skin_L_Finger11 | O |
| Skin_L_Finger2 | finger2 | left | Skin_L_Hand | O |
| Skin_L_Finger21 | finger2 | left | Skin_L_Finger2 | O |
| Skin_L_Finger22 | finger2 | left | Skin_L_Finger21 | O |
| Skin_L_Finger3 | finger3 | left | Skin_L_Hand | O |
| Skin_L_Finger31 | finger3 | left | Skin_L_Finger3 | O |
| Skin_L_Finger32 | finger3 | left | Skin_L_Finger31 | O |
| Skin_L_Finger4 | finger4 | left | Skin_L_Hand | O |
| Skin_L_Finger41 | finger4 | left | Skin_L_Finger4 | O |
| Skin_L_Finger42 | finger4 | left | Skin_L_Finger41 | O |
| Skin_L_Calf | leg | left | Skin_L_Thigh | X |
| Skin_L_Foot | leg | left | Skin_L_Calf | O |
| Skin_L_HorseLink | leg | left | Skin_L_Calf | X |
| Skin_L_Thigh | leg | left | Skin_Pelvis | X |
| Skin_L_Toe0 | leg | left | Skin_L_Foot | O |
| Skin_L_Calf_Seg1 | leg | left | Skin_L_Calf | O |
| Skin_L_Calf_Seg2 | leg | left | Skin_L_Calf | O |
| Skin_L_Calf_Seg3 | leg | left | Skin_L_Calf | O |
| Skin_L_Calf_Seg4 | leg | left | Skin_L_Calf | O |
| Skin_L_Calf_Seg5 | leg | left | Skin_L_Calf | O |
| Skin_L_HorseLink_Seg1 | leg | left | Skin_L_HorseLink | O |
| Skin_L_HorseLink_Seg2 | leg | left | Skin_L_HorseLink | O |
| Skin_L_HorseLink_Seg3 | leg | left | Skin_L_HorseLink | O |
| Skin_L_HorseLink_Seg4 | leg | left | Skin_L_HorseLink | O |
| Skin_L_HorseLink_Seg5 | leg | left | Skin_L_HorseLink | O |
| Skin_L_Thigh_Seg1 | leg | left | Skin_L_Thigh | O |
| Skin_L_Thigh_Seg2 | leg | left | Skin_L_Thigh | O |
| Skin_L_Thigh_Seg3 | leg | left | Skin_L_Thigh | O |
| Skin_L_Thigh_Seg4 | leg | left | Skin_L_Thigh | O |
| Skin_L_Thigh_Seg5 | leg | left | Skin_L_Thigh | O |
| Skin_Prop1 | prop1 | center | Root | O |
| Skin_Prop2 | prop2 | center | Root | O |
| Skin_Prop3 | prop3 | center | Root | O |
| Skin_L_BackA_Skirt1 | extra_skirt | left | Skin_Pelvis | O |
| Skin_L_BackA_Skirt2 | extra_skirt | left | Skin_L_BackA_Skirt1 | O |
| Skin_L_BackA_Skirt3 | extra_skirt | left | Skin_L_BackA_Skirt2 | O |
| Skin_L_FrontA_Skirt1 | extra_skirt | left | Skin_Pelvis | O |
| Skin_L_FrontA_Skirt2 | extra_skirt | left | Skin_L_FrontA_Skirt1 | O |
| Skin_L_FrontA_Skirt3 | extra_skirt | left | Skin_L_FrontA_Skirt2 | O |
| Skin_L_Side_Skirt1 | extra_skirt | left | Skin_Pelvis | O |
| Skin_L_Side_Skirt2 | extra_skirt | left | Skin_L_Side_Skirt1 | O |
| Skin_L_Side_Skirt3 | extra_skirt | left | Skin_L_Side_Skirt2 | O |
| Skin_L_Back_Hip | extra_hip | left | Skin_Pelvis | O |
| Skin_L_Front_Hip | extra_hip | left | Skin_Pelvis | O |
| Skin_L_Side_Hip | extra_hip | left | Skin_Pelvis | O |
| Skin_L_ForeArm_Cor | extra_forearm | left | Skin_L_UpperArm | O |
| Skin_L_Calf_Cor | extra_calf | left | Skin_L_Thigh | O |

> **Right Side** — Replace `_L_` with `_R_` to get the mirrored node.
> e.g. `Skin_L_UpperArm` → `Skin_R_UpperArm`