# F12 — Export / Import Weights (.json)

> SkinLayer Studio **1.3.x Standalone** UI reference.  
> Practice: EP00–EP12 · Features: **F01–F17** (order 50+).

> **What is JSON for?**  
> Transfer **layer weights only**. Backup, Import into another session, Max connector.  
> Mesh/skeleton package or Pick failure → [FBX](/guide/skin-layer-studio/ui-fbx?lang=en).

> Export SLS **layer weights** to a `.json` file, then  
> apply them to Skin in the **3ds Max connector**, or **Import** them back into SLS.

---

## What this does

| | Description |
|--|-------------|
| **Does** | Saves the mesh LayerStack weights (+ meta · bone/vertex info) as **`os_skinLayer_studio` JSON** |
| **Uses** | Backup · offline apply in Max · continue work in another PC/session of SLS |
| **File examples** | `Body_Geo_weights.json`, `Dummy_Body_weights.json` |

Separate from Apply to Skin (live DCC push) — this is a **file-based exchange / restore** path.

---

## Menu locations

```
Tools  →  Export Weights (.json)
Tools  →  Export Weights to Folder...
Tools  →  Import Weights (.json)...
```

![Tools menu — Export / Import JSON](export_json_tools_menu.png)

---

## Export Weights (.json)

| Item | Description |
|------|-------------|
| Target | **Current active** mesh only |
| Action | Choose save path → write `{meshName}_weights.json` |
| Contents | Layer weights · mesh_name meta · bone/vertex info (when available) |

Cannot save if the active slot has no weights yet (before Pick).

---

## Export Weights to Folder...

![Export Weights to Folder](export_json_to_folder.png)

Use when exporting many meshes as JSON into one folder.

| UI | Description |
|----|-------------|
| **Select All** | Select/deselect all in the list |
| Check list | Meshes loaded in Skin Desk (`Body_Geo`, `Dummy_Body`, …) |
| **Export Selected Mesh Weights (JSON)** | Save `{name}_weights.json` for each checked mesh |
| **Cancel** | Close |

After you pick a folder, one file per mesh is created. (On name clash, suffixes like `_weights_2`.)

---

## Reload in SLS (Import)

```
Tools  →  Import Weights (.json)...
```

1. Load the **receiving mesh** into Skin Desk first (Pick)
2. Import Weights → choose the JSON file
3. Match Target mesh and apply

Use this path when restoring a backed-up JSON into SLS.

---

## Load in the 3ds Max connector

In Max, open the **SkinLayer Studio Connector** window, then:

```
[Import Weights (*.json)]
```

1. Add JSON files (multiple OK)
2. Match to scene meshes by filename / `meta.mesh_name`  
   e.g. `Arm_Geo_weights.json` → scene `Arm_Geo`
3. Run Import → apply weights to Max Skin (offline JSON import)

> Connector About also describes this as *Offline JSON weight import utility for 3ds Max*.  
> A same-name mesh must exist in the scene for matching.

---

## Flow at a glance

```
[SLS] Paint · layer work
   │
   ├─ Tools → Export Weights (.json)          ← active 1
   └─ Tools → Export Weights to Folder...     ← multiple meshes
              ↓
         *.json files
              ↓
   ┌──────────┴──────────┐
   ▼                     ▼
[SLS] Import Weights    [3ds Max Connector]
  (.json)...             Import Weights (*.json)
  → edit again           → apply to Max Skin
```

---

## Related docs

| Doc | Contents |
|-----|----------|
| [Transfer Weights · Tools menu](/guide/skin-layer-studio/ui-transfer-weights?lang=en) | Full Tools menu |
| [UI layout guide](/guide/skin-layer-studio/ui-layout-overview?lang=en) | Menu bar · Apply to Skin |
| [Import / Export FBX](/guide/skin-layer-studio/ui-fbx?lang=en) | FBX · Pick alternative |
| Practice EP02 Install | Connector install |

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*Images: `export_json_tools_menu.png` · `export_json_to_folder.png`*  
*Written: 2026-07-26*