Blender Mcp

vladmdgolam/agent-skills/skills/blender-mcp

作者 vladmdgolam5e3e9b95ec52无许可证9 个星标收录于 2026年10月8日更新于 2026年10月8日仓库3周前更新

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.

AI 生成的概览

指导 Blender MCP 工作流:场景检查、Python 提取、GLTF/GLB 导出与纹理优化。

功能
该技能记录了一套分步工作流:通过 MCP 工具检查 Blender 场景,用 bpy Python 脚本提取层级与材质数据,并使用无界面 Blender 命令行导出 GLTF/GLB。随后介绍用 gltf-transform 分步优化导出的 GLB,并对结果进行验证。它还列出常见的导出失败情形,例如程序化纹理和 Color Ramp 节点丢失,以及相应的处理办法。
适用场景
适用于使用 Blender MCP 工具、编写用于提取或修改的 Blender Python 脚本,或为 Three.js 等网页查看器导出 GLTF/GLB 场景时。也用于排查材质或纹理导出丢失问题以及优化 GLB 文件。
运行要求
需要运行中的 Blender MCP 插件与套接字服务器(默认端口 9876)、可用的 Blender 无界面命令行,以及用于 gltf-transform 命令行的 Node/npx。该技能仅附带参考文档,不含脚本。

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_infoexecute_python: print("ok")screenshot

If any step fails, stop and fix MCP connectivity first. See Known Errors.

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 = False        for node in mat.node_tree.nodes:            node_data = {"type": node.type, "name": node.name}            if node.type == 'BSDF_PRINCIPLED':                has_principled = True                for inp in node.inputs:                    if inp.is_linked:                        node_data[inp.name] = "linked"                    elif hasattr(inp, 'default_value'):                        val = inp.default_value                        try:                            node_data[inp.name] = list(val)                        except TypeError:                            node_data[inp.name] = float(val)            if node.type == 'TEX_IMAGE' and node.image:                node_data["image"] = node.image.filepath                node_data["size"] = [node.image.size[0], node.image.size[1]]                if node.image.size[0] > 2048:                    info["warnings"].append(f"Large texture: {node.image.filepath} ({node.image.size[0]}x{node.image.size[1]})")            if node.type in ('TEX_NOISE', 'TEX_VORONOI', 'TEX_WAVE', 'TEX_MUSGRAVE'):                info["warnings"].append(f"Procedural texture node '{node.name}' ({node.type}) will be LOST on GLTF export")            if node.type == 'VALTORGB':  # Color Ramp                info["warnings"].append(f"Color Ramp '{node.name}' remapping will be LOST on GLTF export")        if not has_principled:            info["warnings"].append("No Principled BSDF found — export result unpredictable")        info["nodes"].append(node_data)        materials.append(info)    return materials
result = extract_materials()for mat in result:    if mat["warnings"]:        print(f"WARN [{mat['name']}]: {'; '.join(mat['warnings'])}")print(json.dumps(result, indent=2))

Review all warnings before proceeding. Decide: bake procedural textures now, or patch materials at runtime after export.

Step 4: Export via Headless CLI

The MCP server cannot handle GLTF exports (timeout). Always use headless CLI:

bash
# Use 'blender' if it's on PATH, otherwise use the platform-specific path:#   macOS:   /Applications/Blender.app/Contents/MacOS/Blender#   Windows: "C:\Program Files\Blender Foundation\Blender 4.x\blender.exe"#   Linux:   /usr/bin/blenderblender \  --background "/path/to/scene.blend" \  --python-expr "import bpy, osexport_path = '/path/to/output.glb'os.makedirs(os.path.dirname(os.path.abspath(export_path)), exist_ok=True)bpy.ops.export_scene.gltf(    filepath=export_path,    export_format='GLB',    export_apply=False,    export_animations=True,    export_nla_strips=True,    export_cameras=True,    export_lights=False,    export_draco_mesh_compression_enable=False,)size_mb = os.path.getsize(export_path) / 1024 / 1024print(f'Export complete: {export_path} ({size_mb:.1f} MB)')"

Critical flags:

  • export_apply=False — do not bake modifiers (Array modifier turns 1 MB into 56 MB)
  • export_draco_mesh_compression_enable=False — apply Draco later via gltf-transform
  • Quote all paths that may contain spaces

Step 5: Optimize with gltf-transform

Run after a successful export. Always use individual steps, never optimize:

bash
# 1. Inspect raw export firstnpx @gltf-transform/cli inspect output.glb
# 2. Resize textures (max 1K for web/mobile)npx @gltf-transform/cli resize output.glb resized.glb --width 1024 --height 1024
# 3. WebP compression (quality 90 preserves detail)npx @gltf-transform/cli webp resized.glb webp.glb --quality 90
# 4. Draco mesh compression (LAST — irreversible)npx @gltf-transform/cli draco webp.glb final.glb
# 5. Inspect final resultnpx @gltf-transform/cli inspect final.glb

Expected size reduction: ~22 MB raw → ~3.7 MB (WebP) → ~1 MB (Draco). See references/texture-optimization.md [blocked] for detailed metrics.

Step 6: Validate

Run the full Post-Export Validation checklist below before shipping.

Post-Export Validation Checklist

After every export, verify the following before handing off the GLB for integration:

  • File size is reasonable — raw GLB under 30 MB, optimized GLB under 5 MB for typical web scenes. Flag anything above these thresholds.
  • Inspect with gltf-transform CLI — run npx @gltf-transform/cli inspect final.glb and check: mesh count, texture count, texture sizes, animation count, accessor sizes. No unexpected duplication.
  • Visual test in Babylon.js Sandbox — drag-and-drop the GLB at sandbox.babylonjs.com. Verify: mesh renders correctly, textures appear, animations play, no black/pink materials.
  • No Three.js console errors — load in a minimal Three.js GLTFLoader test page and check browser console. Common errors: THREE.GLTFLoader: Unknown extension, missing texture files, unsupported Draco version.
  • Materials spot-check — pick 3–5 materials and visually confirm roughness, metalness, and base color look correct. Compare against Blender viewport render. Flag any that look flat or overly shiny.
  • Animation spot-check — if the scene has animations, verify at least one plays correctly in Babylon.js Sandbox or Three.js. Check frame count matches expected.
  • Name mapping verified — if runtime code references mesh names, confirm the names match after GLTF export transformation (spaces → underscores, dots removed). See Critical Rule 5.
  • No missing textures — check Babylon.js Sandbox network tab. No 404s for texture files. All textures should be packed inside the GLB.

Examples

Example 1: Export Character Rig with Animations

Scenario: You have a humanoid character with armature, 3 NLA actions (idle, walk, run), PBR texture set, and a weapon attached via parenting. You need a web-ready GLB for a Three.js scene.

Step 1: Health check and scene inspection

bash
# MCP tool callsget_scene_infoexecute_python: print("ok")

Step 2: Inspect the rig

python
import bpy, json
# Check armature and NLA stripsfor obj in bpy.data.objects:    if obj.type == 'ARMATURE':        print(f"Armature: {obj.name}")        if obj.animation_data:            print(f"  Active action: {obj.animation_data.action.name if obj.animation_data.action else 'None'}")            for track in obj.animation_data.nla_tracks:                print(f"  NLA track: {track.name}")                for strip in track.strips:                    print(f"    Strip: {strip.name}, frames {strip.frame_start}-{strip.frame_end}")

Step 3: Check materials for export losses

Run the material extraction above. For a character, watch for:

  • Procedural skin texture nodes (Noise → color variation) — these will be lost
  • Color Ramp on roughness for fabric — will be lost, roughness will look flat
  • Decision: bake procedural variations to image textures, or patch roughness values at runtime

Step 4: Export

bash
blender \  --background "/path/to/character.blend" \  --python-expr "import bpy, os, tempfileexport_dir = tempfile.gettempdir()bpy.ops.export_scene.gltf(    filepath=os.path.join(export_dir, 'character.glb'),    export_format='GLB',    export_apply=False,    export_animations=True,    export_nla_strips=True,    export_cameras=False,    export_lights=False,    export_draco_mesh_compression_enable=False,    export_skins=True,    export_morph=True,)print('done:', os.path.getsize(os.path.join(export_dir, 'character.glb')) / 1024 / 1024, 'MB')"

Step 5: Verify animations exported

bash
npx @gltf-transform/cli inspect character.glb | grep -i anim

Expected output: 3 animations (Idle, Walk, Run). If 0, check that NLA strips are muted or the tracks are set to solo.

Step 6: Optimize

bash
npx @gltf-transform/cli resize character.glb char_resized.glb --width 1024 --height 1024npx @gltf-transform/cli webp char_resized.glb char_webp.glb --quality 90npx @gltf-transform/cli draco char_webp.glb character_final.glb

Step 7: Runtime animation setup (Three.js)

javascript
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';import { DRACOLoader } from 'three/addons/loaders/DRACOLoader.js';import * as THREE from 'three';
const dracoLoader = new DRACOLoader();dracoLoader.setDecoderPath('/draco/');
const loader = new GLTFLoader();loader.setDRACOLoader(dracoLoader);
loader.load('/character_final.glb', (gltf) => {    const mixer = new THREE.AnimationMixer(gltf.scene);    const clips = gltf.animations; // [Idle, Walk, Run]    const idleAction = mixer.clipAction(clips.find(c => c.name === 'Idle'));    idleAction.play();    // Animate mixer in render loop: mixer.update(delta)});

Example 2: Debug Material Export Loss (Roughness Looks Flat)

Scenario: After export, a metal panel material looks uniformly flat and shiny in Three.js. In Blender it had interesting roughness variation from a Noise Texture → Color Ramp → roughness input.

Step 1: Confirm the problem in Blender

python
import bpy, json
mat = bpy.data.materials.get("MetalPanel")if mat and mat.use_nodes:    for node in mat.node_tree.nodes:        print(f"Node: {node.type} - {node.name}")        for inp in node.inputs:            if inp.is_linked:                print(f"  Input '{inp.name}': linked to something")

Expected output reveals:

Node: BSDF_PRINCIPLED - Principled BSDF  Input 'Roughness': linked to somethingNode: VALTORGB - Color Ramp         <-- this will NOT exportNode: TEX_NOISE - Noise Texture     <-- this will NOT export

Step 2: Understand what GLTF received

The export exports the Principled BSDF's roughness input. When linked to a Color Ramp, GLTF exporter takes the default_value of the input socket (fallback), which is typically 0.5 — perfectly flat.

Step 3A: Fix by baking in Blender (best quality)

python
import bpy
# Select the objectobj = bpy.data.objects["MetalPanelMesh"]bpy.context.view_layer.objects.active = objbpy.ops.object.select_all(action='DESELECT')obj.select_set(True)
# Create a new image to bake intobake_img = bpy.data.images.new("MetalPanel_roughness_baked", width=1024, height=1024)bake_img.colorspace_settings.name = 'Non-Color'
# Add image texture node to materialmat = obj.active_materialnodes = mat.node_tree.nodesimg_node = nodes.new('ShaderNodeTexImage')img_node.image = bake_imgnodes.active = img_node
# Bake roughness (use ROUGHNESS pass or EMIT trick)bpy.context.scene.cycles.bake_type = 'ROUGHNESS'bpy.ops.object.bake(type='ROUGHNESS', save_mode='INTERNAL')
# Save baked imageimport tempfile, osbake_path = os.path.join(tempfile.gettempdir(), 'MetalPanel_roughness_baked.png')bake_img.filepath_raw = bake_pathbake_img.file_format = 'PNG'bake_img.save()print(f"Baked roughness to {bake_path}")

Then connect the new image texture node to the Roughness input and re-export.

Step 3B: Fix at runtime in Three.js (quick patch)

If you cannot bake, override the material roughness after load:

javascript
loader.load('/metal_panel.glb', (gltf) => {    gltf.scene.traverse((child) => {        if (child.isMesh && child.material) {            const mats = Array.isArray(child.material) ? child.material : [child.material];            mats.forEach(mat => {                if (mat.name === 'MetalPanel') {                    // Instead of flat 0.5, set a textured roughness or varied value                    mat.roughness = 0.3;  // adjust to match intended look                    mat.metalness = 0.9;                    mat.needsUpdate = true;                }            });        }    });});

Step 4: Verify fix

Re-export and run validation checklist. In Babylon.js Sandbox, compare the metal panel material against a Blender viewport screenshot to confirm roughness variation is preserved.

Critical Rules

1. MCP Server Times Out on Exports

The Blender MCP server cannot handle GLTF exports — they exceed the timeout. Always use headless CLI:

bash
blender --background "scene.blend" --python-expr "import bpy, osexport_path = 'output.glb'os.makedirs(os.path.dirname(export_path), exist_ok=True)bpy.ops.export_scene.gltf(    filepath=export_path,    export_format='GLB',    export_apply=False,    export_animations=True,    export_nla_strips=True,    export_cameras=True,    export_lights=False,    export_draco_mesh_compression_enable=False,)print(f'Size: {os.path.getsize(export_path)/1024/1024:.1f} MB')"

2. Do NOT Apply Modifiers on Export

Set export_apply=False. Array modifiers (circular patterns, linear repeats) balloon file size when baked. Replicate them at runtime instead.

Example: 16 roller instances via Array modifier = ~1 MB GLB. Baked = ~56 MB GLB.

3. Export WITHOUT Draco First

If you plan to optimize with gltf-transform, export without Draco compression. Re-encoding existing Draco corrupts meshes. Apply Draco as the final step.

4. Procedural Textures Don't Export to GLTF

These Blender node setups are lost on export:

Node SetupWhat's LostWorkaround
Noise Texture → roughnessEntire procedural chainBake to texture, or shader patch at runtime
Color Ramp on roughness textureValue remapping rangeManual roughness values, or runtime remap
Procedural bump (Noise → Bump)Bump detailBake normal map in Blender
Mix Shader with complex factorBlend logicSimplify to single BSDF before export

What DOES export: flat roughness/metallic values, image textures (without Color Ramp remapping), baked normal maps, PBR texture sets (baseColor, metallicRoughness, normal).

5. GLTF Name Mapping

Blender names are transformed in GLTF:

  • Spaces → underscores
  • Dots → removed
  • Trailing spaces → trailing underscore
BlenderGLTF
RINGS ball LRINGS_ball_L
Sphere.003Sphere003
RINGS L.001RINGS_L001
RINGS S (trailing space)RINGS_S_

Always check names in the exported GLB, not Blender, when referencing meshes in code.

6. Never Use gltf-transform optimize

The optimize command includes simplify which destroys mesh geometry. Use individual steps instead:

bash
# Resize textures (max 1024x1024)npx @gltf-transform/cli resize input.glb resized.glb --width 1024 --height 1024
# WebP texture compressionnpx @gltf-transform/cli webp resized.glb webp.glb --quality 90
# Draco mesh compression (LAST step)npx @gltf-transform/cli draco webp.glb output.glb

7. Quote Paths with Spaces

Blender project paths often contain spaces. Always double-quote:

bash
blender --background "$HOME/Downloads/blend 3/scene.blend" ...

Scene Extraction Pattern

Full hierarchy with materials, transforms, and modifiers:

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)        if obj.data.type == 'AREA':            data["size"] = obj.data.size            data["size_y"] = obj.data.size_y    # Array modifiers (important for runtime replication)    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))

Material Extraction Pattern

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": []}        for node in mat.node_tree.nodes:            node_data = {"type": node.type, "name": node.name}            if node.type == 'BSDF_PRINCIPLED':                for inp in node.inputs:                    if inp.is_linked:                        node_data[inp.name] = "linked"                    elif hasattr(inp, 'default_value'):                        val = inp.default_value                        try:                            node_data[inp.name] = list(val)                        except TypeError:                            node_data[inp.name] = float(val)            if node.type == 'TEX_IMAGE' and node.image:                node_data["image"] = node.image.filepath                node_data["size"] = [node.image.size[0], node.image.size[1]]            info["nodes"].append(node_data)        materials.append(info)    return materials
print(json.dumps(extract_materials(), indent=2))

Animation Keyframe Extraction

python
import bpy, json
def extract_animation(obj):    if not obj.animation_data or not obj.animation_data.action:        return None    tracks = []    for fc in obj.animation_data.action.fcurves:        keyframes = []        for kp in fc.keyframe_points:            keyframes.append({                "frame": int(kp.co[0]),                "value": float(kp.co[1]),                "interpolation": kp.interpolation,            })        tracks.append({            "data_path": fc.data_path,            "index": fc.array_index,            "keyframes": keyframes,        })    return {"object": obj.name, "tracks": tracks}
animations = []for obj in bpy.data.objects:    anim = extract_animation(obj)    if anim:        animations.append(anim)
print(json.dumps(animations, indent=2))

GLTF Export Settings Reference

SettingValueWhy
export_format'GLB'Single binary file
export_applyFalseDon't bake modifiers (Array, etc.)
export_animationsTrueInclude animation data
export_nla_stripsTrueBake NLA strips into actions
export_camerasTrueInclude camera rigs
export_lightsFalseHandle lights in runtime (Three.js/R3F)
export_draco_mesh_compression_enableFalseApply Draco later via gltf-transform

Texture Optimization Pipeline

Target: smallest GLB with acceptable visual quality.

Blender export (no Draco) → resize (1K max) → WebP (q90) → Draco   ~22 MB                    ~3.7 MB           ~3.7 MB      ~1 MB

Key insights:

  • 4K textures (4096x4096) = ~89 MB GPU memory per texture. 1K = ~5.6 MB. 16x reduction.
  • PNG metallicRoughness textures compress well to WebP at quality 85-90.
  • Mobile GPUs (Adreno, Mali) benefit most from texture downscaling.
  • Inspect with: npx @gltf-transform/cli inspect model.glb

See references/texture-optimization.md [blocked] for concrete commands and quality metrics.

Asset Integrations

Available through Blender MCP when configured:

IntegrationCapabilities
PolyHavenSearch, download, import free HDRIs, textures, and 3D models with auto material setup
SketchfabSearch and download models (requires access token)
Hyper3D RodinGenerate 3D models from text descriptions or reference images
Hunyuan3DCreate 3D assets from text prompts, images, or both

See references/asset-integrations.md [blocked] for usage examples and workflow patterns.

Known Errors & Workarounds

See references/errors.md [blocked] for complete error tables.

Data Output

  • print() + json.dumps() for small results (scene info, single object)
  • Use tempfile.gettempdir() for large extraction results (full hierarchy, animation data, material reports)
  • Always include metadata: scene name, fps, frame range, Blender version

来源与署名

来源:vladmdgolam/agent-skills位于skills/blender-mcp提交5e3e9b9

许可证: 无许可证

内容归原作者所有。SourceWeft 从公开仓库中收录这些内容。

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