# Ep.5 — Skinning Preparation · Rig/Skin Layer Separation · SkinLayer Studio

https://youtu.be/hGpNiXwD6FY?si=j3j_AbSRPGg0Yk2h

## Overview

This video explains, **before** starting serious skinning (weighting) work, **why BipedPlus separates** the **rigging layer** from the **skin layer**.  
It also covers why 3ds Max **default skinning** is challenging and what **SkinLayer Studio** offers.

## Core Concept: Two Layers

The BipedPlus rig is divided into **two layers with different roles**.

```
[ Rigging Layer ]   Controllers the animator moves, constraints, etc.
       ↕
[ Skin Bone Layer ] Bones that receive mesh weights and are exported to the game engine
```

**Remember:** When assigning weights, attach them to **"Skin Bones"**. Do not skin directly to controllers.

- The **method** of skinning (adding bones, entering values) is similar to standard Max workflow.
- What matters is **which layer's bones you select**.

## 3ds Max Default Skinning — Why It's Difficult

| Problem | In Plain Terms |
|---------|----------------|
| **Dated workflow** | UI and workflow feel **cumbersome** even by 2026 standards |
| **Many bones** | Hard to divide weights by zone for Twist, Corrective, etc. |
| **Higher quality bar** | More polys and bones than old mobile projects — **rough work no longer passes** |
| **Envelope** | Real-time zone editing — can get **complex and slow** |

### Recommendation for BipedPlus Rigs

- Instead of Envelopes, entering **values per vertex directly** is recommended (per the video).
- Rigs with **many bones** like BipedPlus can take **extremely long** if done entirely with the Max Skin Modifier alone.

## What Is SkinLayer Studio

**Layer-based skinning** — stack weights **region by region**, like Photoshop layers.

| Layer Example | Responsible Area |
|---------------|-----------------|
| Pelvis | Pelvis only |
| Spine | Back · Waist |
| Neck | Neck |
| Thigh · Knee | Thigh · Knee |

- Each layer has a **painted mask**, making **edits and left/right mirroring** convenient.
- Even with **complex bones**, work is divided **one region at a time**.
- **Linked to the Max viewport** — check motion in real time while playing back.
- Workflow speed is also **relatively fast** (team experience).

> SkinLayer Studio is a **separate tool from BipedPlus**, but it is being developed by the **same team** and is designed to work alongside skin work.

## Difference from Other Skinning Tools

- **Auto-skin-focused** tools: may be fine for the torso, but have limits for **facial or high-bone-count** characters.
- The approach of **managing zones with layers** (SkinLayer Studio, etc.) is considered **more manageable** by current standards.

## Pre-Practice Checklist

1. Ep.1–4 **Build · Figure · Controller** complete.
2. **Mesh** to skin prepared.
3. Think from **large regions first: pelvis → spine → legs…**
4. Rather than using the Max Skin Modifier **alone**, using **SkinLayer Studio** or the **team's designated skin tool** is recommended.

## Difference from Ep.6

| Ep.5 (This) | Ep.6 (Next) |
|-------------|-------------|
| **Why** to separate, and **which tool** to use for skinning | BipedPlus **Skin tab** for weight **save / load / disable** |

## Notes

- If your team **already has a good skin tool**, use that.
- The Ep.6 **Skin tab** is for **data management** — it is a different screen from **painting** skin.