# Ep.20 — Convert Tip · Weight→Seg Analysis · .fig

https://youtu.be/dt8k3gpBaeU

## Overview

**Ep.19 Convert (FBX)** covers the **8-step pipeline**. This tip video is for when convert **does not match expectations** — start with **pre-analysis**.

> **Before convert, read Weight concentration and note Seg 1·2·3. Step 3 Mapping becomes much more accurate.**

Walkthrough: leg → arm → Step 3 manual assignment → `.fig` + FBX import → build (example character used with customer permission).

## What's covered

| Section | Content |
|---------|---------|
| Pre-analysis | Thigh / Calf / UpperArm / ForeArm Weight → Seg |
| Quality tip | Use Figure Mode **`.fig`** with FBX |
| Step 3 | Refine auto analysis · Skip/replace · temp Rename |
| After | Hierarchy · Skin save · Legacy · Import · Parent · Picker |

## Related

**Ep.19** Convert pipeline · **Ep.1–3** Build/Figure · **Ep.6** Skin · **Ep.8** Picker · **SkinLayer Studio** for weight cleanup

## 1. Why Body and Twist matter

Game rigs are often **Biped-based**. Extra bones (skirts, accessories) are usually simple chains for spring later. Custom Maya-style skirts are more complex; Max game rigs keep Extra simple — so Convert success hinges on **Body + Twist** analysis.

1. **Body** — Weight ↔ Seg mapping  
2. **Twist** — end-biased vs missing mid band  
3. **Extra** — leave unmatched bones; Parent later in Hierarchy

## 2. Pre-analysis method

Prefer **Layers → Sort by Hierarchy** and **Weight view** over Schematic alone.

| Observation | Seg note |
|-------------|----------|
| Weight biased to **root/start** | **Seg 1** |
| Mid weight band | **Seg 2** |
| Twist / weight biased to **end** | **Seg 3** (when using 3 twists) |

Reduced bone-count setups often mix Biped + Twist weights. Missing Seg 2 is OK for convert — fill later if needed.

### Leg / arm patterns (video)

- **Thigh** end-biased → Seg **3**; **Calf** Biped → Seg **1**; **Calf Twist** end → Seg **3**
- **UpperArm** Biped → Seg **3**; Twist1 → **2**; Twist2 → **3**
- **ForeArm** Biped → **1**; Twist ForeArm → **3**; mid Seg 2 may be empty
- Knee often mirrors forearm: Biped **1**, Twist **3**
- Spine / Neck / Head need Seg placement for stretch/squash — focus the **second analysis table**

## 3. Better quality with `.fig`

From Figure Mode, save a **`.fig`**. Convert is FBX-based, but importing **FBX + `.fig`** gets closer to the original figure and raises convert quality.

1. Save `.fig` in Figure Mode  
2. Export skinned FBX (see Ep.19 prep)  
3. Step 1: import **FBX + `.fig`**

## 4. Step 3 — manual Seg (critical)

After Analyze (video: Leg Link 3, Twist 3, no reverse leg), refine Mapping. Auto analysis helps but is imperfect — use your Weight notes.

1. Search UpperArm / ForeArm / Thigh…  
2. Assign the matching **Seg**  
3. If occupied → **Skip** then **Yes** to replace  
4. This is a **temporary Rename** so Skinning lands on the intended Segs

Leave Extra bones without BipedPlus counterparts as-is.

## 5. After Step 4

Init Point → Hierarchy/Skin save → **Legacy** prefix → Step 7 Import → Parent extras → Skin load + cleanup temps → Picker / Scale / Stretching check.

**Stretching note:** 3 Segs (e.g. Thigh) arc cleanly; 2-bone joints may not. Rebalance weights afterward (SkinLayer Studio or stock Skin) once the convert base is solid.

## 6. Stuck?

Email / open chat / messenger: `contact@otakusolutions.com` · [BipedPlus](https://otakusolutions.com/ko/biped-plus)