# Skill: 3D Model Generation with Tripo Studio

Generate 3D models from text descriptions or 2D images using [Tripo Studio](https://studio.tripo3d.ai). This skill covers the workflow for game-ready 3D assets.

## Overview

Tripo Studio is a web-based text-to-3D and image-to-3D tool. You describe a character, prop, or environment piece --- or upload concept art --- and Tripo generates a textured 3D model in ~60 seconds.

**Output:** GLB or FBX with full PBR textures (basecolour, normal, ORM/metallic/roughness).

**Cost:** ~25-50 credits per generation. Free tier: 150 credits/month.

## When to Use

- You have approved 2D concept art and need a 3D model
- You need a quick 3D prototype from a text description
- You're generating props, characters, or environment pieces for a game
- You need multiple variants of the same object

## Workflow

### Text-to-3D

1. Open [Tripo Studio](https://studio.tripo3d.ai)
2. Click **Create** -> **Text to 3D**
3. Enter your prompt (see prompt tips below)
4. Settings:
   - Quality: **Ultra**
   - Model: **v3.1 Best Quality** (or latest)
   - Texture: **ON** (critical --- generates PBR maps)
5. Click Generate (~35-50 credits, ~60s)
6. Review the model in the 3D viewer --- rotate, check materials
7. Export as **GLB** (preferred) or FBX

### Image-to-3D

1. Upload your approved concept art (front view, T-pose for characters)
2. Settings: same as text-to-3D
3. Generate
4. Review --- check if the back and sides match your expectations
5. Export

## Prompt Tips for Game Assets

### Characters

```
Full body character, T-pose, front facing. Young Polynesian woman wearing
woven pandanus skirt and tapa cloth top. Shell necklace, flower in hair.
Stylized game character, not photorealistic. Clean topology.
```

**Key rules:**
- Always specify **T-pose** for characters (needed for rigging)
- Mention **clean topology** to reduce mesh artifacts
- Describe clothing and accessories explicitly
- Specify art style (stylized, realistic, low-poly, etc.)

### Props

```
Carved wooden fishing spear with bone tip. Wrapped handle with
woven cord. Polynesian style, game prop, stylized.
```

### Environment pieces

```
Thatched-roof hut on wooden stilts. Open sides with woven wall panels.
Polynesian longhouse style. Game-ready, stylized 3D.
```

## Post-Generation Tools

Tripo offers several refinement tools after generation:

| Tool | Purpose | When to Use |
|------|---------|-------------|
| **Segment** | Split model into parts | Characters with large hair (split hair from body for rigging) |
| **Retopo** | Retopologize mesh | When face count is too high or topology is bad |
| **Texture** | Regenerate textures | When colours don't match concept art |
| **Animate** | Add basic animations | Quick previews (not production quality) |
| **Edit** | Modify the model | Remove artifacts, adjust proportions |

## Export Options

| Format | Use |
|--------|-----|
| **GLB** | Preferred. Single file, preserves PBR textures, works everywhere |
| **FBX** | When your pipeline requires it (Unity, some Blender workflows) |
| OBJ | Legacy. Loses PBR data. Avoid. |
| USD | For USD-based pipelines |
| STL | 3D printing only. No textures. |

## Polygon Budget

Tripo outputs ~1.5M faces by default. You'll need to decimate:

| LOD | Target Faces | Method |
|-----|-------------|--------|
| LOD0 | 25,000 | Blender Decimate modifier or CLI |
| LOD1 | 10,000 | Same |
| LOD2 | 2,500 | Same |

Use Tripo's built-in **Retopo** tool for a quick reduction, or decimate in Blender for more control.

## The Large Hair Problem

Auto-riggers (Mixamo, Godot's skeleton system) break when character meshes include large or complex hairstyles. The rig misidentifies the hair volume as part of the body.

**Solution:**
1. After generation, use Tripo's **Segment** tool
2. Select the hair and split it from the body
3. Export the **body-only** mesh for rigging
4. Export hair separately
5. Reattach hair after rigging in Blender or your engine

Flag this in your handoff document for every character with big hair.

## Batch Generation

When generating multiple assets in one session:

1. Prepare all prompts upfront
2. Generate in priority order
3. Use the 3 free retries per generation before spending more credits
4. Score and review each model immediately
5. Track remaining credits
6. Export approved models right away --- don't leave them only in the cloud

## Credit Optimisation

| Action | Credits |
|--------|---------|
| Standard quality generation | ~15-25 |
| Ultra quality generation | ~35-50 |
| Retopo | ~10-15 |
| Texture regeneration | ~10 |
| Segment | ~5 |

**Tip:** Start with Standard quality for exploration, switch to Ultra only for final approved designs.

## Common Mistakes

| Problem | Fix |
|---------|-----|
| Model has no textures | Ensure Texture is ON before generating |
| Back of character looks wrong | Use image-to-3D with front AND back views, or add "detailed back view" to prompt |
| Mesh has floating geometry | Use Edit tool to clean up, or regenerate |
| Merged fingers | Common artifact. Regenerate or fix in Blender |
| Too many polygons for game use | Use Retopo tool or Blender Decimate |
| Hair breaks auto-rigger | Segment hair from body, rig body-only |

## Related Skills

- [Image Generation](image-generation.md) --- create 2D concept art to feed into Tripo
- [Concept Art Pipeline](concept-art-pipeline.md) --- full 2D-to-3D workflow