blender-mcp

Este extracto es una copia guardada durante la revisión. La fuente externa contiene la versión completa y actual.

---
name: blender-mcp
description: "Blender MCP expert for scene inspection, Python scripting, GLTF export, and material/animation extraction. Activate when: (1) using Blender MCP tools (get_scene_info, execute_python, screenshot, etc.), (2) writing Blender Python scripts for extraction or manipulation, (3) exporting scenes to GLTF/GLB for web (Three.js, R3F), (4) debugging material or texture export losses, (5) optimizing GLB files with gltf-transform, (6) using asset integrations (PolyHaven, Sketchfab, Hyper3D Rodin, Hunyuan3D). Covers critical export gotchas, material mapping survival, texture optimization pipeline, headless CLI patterns, and known failure modes."
---

# Blender MCP

## Tool Selection

Use **structured MCP tools** (`get_scene_info`, `screenshot`) for quick inspection.

Use **`execute_python`** for anything non-trivial: hierarchy traversal, material extraction, animation baking, bulk operations. It gives full `bpy` API access and avoids tool schema limitations.

Use **headless CLI** for GLTF exports — the MCP server times out on export operations.

## Health Check (Always First)

1. `get_scene_info` — verify connection (default port 9876)
2. `execute_python` with `print("ok")` — verify Python works
3. `screenshot` — verify viewport capture works

If MCP is unresponsive, check that the Blender MCP addon is enabled and the socket server is running.

## Complete Export Workflow

This is the end-to-end linear narrative. Follow these steps in order. Do not skip steps.

### Step 1: Health Check

Confirm MCP is alive before touching anything else:

```bash
# In MCP tool call:
get_scene_info
execute_python: print("ok")
screenshot
```

If any step fails, stop and fix MCP connectivity first. See [Known Errors](#known-errors--workarounds).

### Step 2: Inspect Scene

Run the full hierarchy extraction to understand what you're working with:

```python
import bpy, json

def extract_hierarchy(obj, depth=0):
    data = {
        "name": obj.name,
        "type": obj.type,
        "location": list(obj.location),
        "rotation": list(obj.rotation_euler),
        "scale": list(obj.scale),
        "visible": not obj.hide_viewport,
        "children": [],
    }
    if obj.type == 'MESH' and obj.data:
        data["vertices"] = len(obj.data.vertices)
        data["faces"] = len(obj.data.polygons)
        data["materials"] = [slot.material.name for slot in obj.material_slots if slot.material]
    if obj.type == 'LIGHT':
        data["light_type"] = obj.data.type
        data["energy"] = obj.data.energy
        data["color"] = list(obj.data.color)
    for mod in obj.modifiers:
        if mod.type == 'ARRAY':
            data.setdefault("modifiers", []).append({
                "type": "ARRAY",
                "count": mod.count,
                "offset_object": mod.offset_object.name if mod.offset_object else None,
            })
    for child in obj.children:
        data["children"].append(extract_hierarchy(child, depth + 1))
    return data

scene_data = {
    "name": bpy.context.scene.name,
    "fps": bpy.context.scene.render.fps,
    "frame_start": bpy.context.scene.frame_start,
    "frame_end": bpy.context.scene.frame_end,
    "objects": [],
}
for obj in bpy.context.scene.objects:
    if obj.parent is None:
        scene_data["objects"].append(extract_hierarchy(obj))

print(json.dumps(scene_data, indent=2))
```

Look for:
- Array modifiers (will balloon file size if baked — must replicate at runtime)
- Objects with many vertices (risk of slow export or large GLB)
- Hidden objects you may or may not want to export
- Missing materials (empty `material_slots`)

### Step 3: Verify Materials

Run the material extraction to catch export-lossy setups before committing to an export:

```python
import bpy, json

def extract_materials():
    materials = []
    for mat in bpy.data.materials:
        if not mat.use_nodes:
            continue
        info = {"name": mat.name, "nodes": [], "warnings": []}
        has_principled = Fal