Creating 3D Assets with Blender MCP

This skill enables creating, modifying, and exporting 3D assets directly from Blender using the Model Context Protocol (MCP). Assets can be used in StickerNest's spatial canvas, VR/AR experiences, and 3D widgets.

Prerequisites

Blender Setup

•Install Blender 3.0+ from blender.org
•Download the addon.py from ahujasid/blender-mcp
•In Blender: Edit > Preferences > Add-ons > Install > Select addon.py
•Enable "Interface: Blender MCP" addon

Connect to Claude

•Open Blender and press N to show the sidebar
•Find the "BlenderMCP" tab
•Click "Connect to Claude"
•The MCP server will start on port 9876

When to Use This Skill

This skill helps when you need to:

•Create 3D primitives (cubes, spheres, cylinders, etc.)
•Generate procedural geometry with Python
•Apply materials and colors to objects
•Export web-ready 3D models (GLB/GLTF)
•Automate repetitive 3D tasks
•Create assets for StickerNest widgets

Core Concepts

The bpy Module

Blender's Python API is exposed through the bpy module:

•bpy.context - Current state (active object, selected objects, scene)
•bpy.data - Access to all data (meshes, materials, objects)
•bpy.ops - Operators that perform actions (like menu commands)

Object vs Mesh vs Material

•Object: Container with transform (location, rotation, scale)
•Mesh: Actual geometry data (vertices, edges, faces)
•Material: Surface appearance (color, roughness, metallic)

Coordinate System

Blender uses right-handed Y-up coordinates. When exporting to Three.js/R3F (Y-up), models export correctly. For Unity (Y-up converted), use export options.

Step-by-Step Guides

Creating Basic Primitives

python

import bpy

# Clear existing objects
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete()

# Create a cube
bpy.ops.mesh.primitive_cube_add(
    size=2,
    location=(0, 0, 1)
)
cube = bpy.context.active_object
cube.name = "MyCube"

# Create a sphere
bpy.ops.mesh.primitive_uv_sphere_add(
    radius=1,
    segments=32,
    ring_count=16,
    location=(3, 0, 1)
)

# Create a cylinder
bpy.ops.mesh.primitive_cylinder_add(
    radius=0.5,
    depth=2,
    vertices=32,
    location=(-3, 0, 1)
)

Applying Materials

python

import bpy

# Get the active object
obj = bpy.context.active_object

# Create a new material
mat = bpy.data.materials.new(name="SN_PurpleAccent")
mat.use_nodes = True

# Configure the Principled BSDF shader
bsdf = mat.node_tree.nodes["Principled BSDF"]
# StickerNest purple accent: #8b5cf6 = RGB(139, 92, 246)
bsdf.inputs["Base Color"].default_value = (139/255, 92/255, 246/255, 1.0)
bsdf.inputs["Metallic"].default_value = 0.0
bsdf.inputs["Roughness"].default_value = 0.4

# Assign material to object
if obj.data.materials:
    obj.data.materials[0] = mat
else:
    obj.data.materials.append(mat)

Adding Modifiers

python

import bpy

obj = bpy.context.active_object

# Subdivision Surface (smooth geometry)
subsurf = obj.modifiers.new(name="Subdivision", type='SUBSURF')
subsurf.levels = 2
subsurf.render_levels = 3

# Bevel (rounded edges)
bevel = obj.modifiers.new(name="Bevel", type='BEVEL')
bevel.width = 0.02
bevel.segments = 2

# Solidify (add thickness to surfaces)
solidify = obj.modifiers.new(name="Solidify", type='SOLIDIFY')
solidify.thickness = 0.1

# Apply all modifiers
for mod in obj.modifiers:
    bpy.ops.object.modifier_apply(modifier=mod.name)

Creating Procedural Geometry

python

import bpy
import bmesh
from mathutils import Vector

# Create new mesh
mesh = bpy.data.meshes.new("ProceduralMesh")
obj = bpy.data.objects.new("ProceduralObject", mesh)
bpy.context.collection.objects.link(obj)

# Use bmesh for procedural creation
bm = bmesh.new()

# Create a custom shape (star)
import math
verts = []
for i in range(10):
    angle = math.radians(i * 36)
    radius = 1.0 if i % 2 == 0 else 0.5
    x = math.cos(angle) * radius
    y = math.sin(angle) * radius
    verts.append(bm.verts.new((x, y, 0)))

# Create face from vertices
bmesh.ops.contextual_create(bm, geom=verts)

# Extrude for thickness
bmesh.ops.extrude_face_region(bm, geom=bm.faces[:])
for v in bm.verts:
    if v.select:
        v.co.z += 0.2

bm.to_mesh(mesh)
bm.free()

Exporting for Web (GLB)

python

import bpy

# Select objects to export
bpy.ops.object.select_all(action='DESELECT')
for obj in bpy.context.scene.objects:
    if obj.type == 'MESH':
        obj.select_set(True)

# Export as GLB (binary GLTF)
bpy.ops.export_scene.gltf(
    filepath="C:/Users/Kimber/StickerNestV3-4/public/assets/3d/my-asset.glb",
    use_selection=True,
    export_format='GLB',
    export_apply=True,  # Apply modifiers
    export_texcoords=True,
    export_normals=True,
    export_materials='EXPORT',
    export_colors=True,
    export_cameras=False,
    export_lights=False,
    export_yup=True  # Convert to Y-up for Three.js
)

Common Patterns

Pattern: StickerNest-Themed Object

Create objects with StickerNest's color palette:

python

import bpy

# StickerNest theme colors
SN_COLORS = {
    'bg_primary': (15/255, 15/255, 25/255, 1),      # #0f0f19
    'bg_secondary': (26/255, 26/255, 46/255, 1),    # #1a1a2e
    'accent_primary': (139/255, 92/255, 246/255, 1), # #8b5cf6
    'accent_secondary': (236/255, 72/255, 153/255, 1), # #ec4899
    'success': (34/255, 197/255, 94/255, 1),        # #22c55e
    'error': (239/255, 68/255, 68/255, 1),          # #ef4444
}

def create_sn_material(name, color_key, metallic=0.0, roughness=0.4):
    mat = bpy.data.materials.new(name=f"SN_{name}")
    mat.use_nodes = True
    bsdf = mat.node_tree.nodes["Principled BSDF"]
    bsdf.inputs["Base Color"].default_value = SN_COLORS[color_key]
    bsdf.inputs["Metallic"].default_value = metallic
    bsdf.inputs["Roughness"].default_value = roughness
    return mat

# Usage
accent_mat = create_sn_material("Accent", "accent_primary")

Pattern: Widget Frame

Create a standard frame for 3D widgets:

python

import bpy

def create_widget_frame(width=2, height=1.5, depth=0.1, corner_radius=0.1):
    # Create base plane
    bpy.ops.mesh.primitive_plane_add(size=1)
    frame = bpy.context.active_object
    frame.name = "WidgetFrame"

    # Scale to dimensions
    frame.scale = (width, height, 1)
    bpy.ops.object.transform_apply(scale=True)

    # Add solidify for depth
    solidify = frame.modifiers.new("Solidify", 'SOLIDIFY')
    solidify.thickness = depth

    # Add bevel for rounded corners
    bevel = frame.modifiers.new("Bevel", 'BEVEL')
    bevel.width = corner_radius
    bevel.segments = 4

    # Apply modifiers
    bpy.ops.object.modifier_apply(modifier="Solidify")
    bpy.ops.object.modifier_apply(modifier="Bevel")

    return frame

# Create a 4:3 widget frame
frame = create_widget_frame(width=2, height=1.5)

Pattern: Batch Asset Generation

Generate multiple variations of an asset:

python

import bpy
import math

def generate_icon_set(base_shape='sphere', variations=5):
    """Generate a set of icon variations"""

    assets = []

    for i in range(variations):
        # Clear selection
        bpy.ops.object.select_all(action='DESELECT')

        # Create base shape
        if base_shape == 'sphere':
            bpy.ops.mesh.primitive_uv_sphere_add(radius=0.5)
        elif base_shape == 'cube':
            bpy.ops.mesh.primitive_cube_add(size=1)
        elif base_shape == 'cylinder':
            bpy.ops.mesh.primitive_cylinder_add(radius=0.5, depth=0.2)

        obj = bpy.context.active_object
        obj.name = f"Icon_{base_shape}_{i}"

        # Apply unique transformation
        obj.location = (i * 1.5, 0, 0)
        obj.rotation_euler.z = math.radians(i * 15)

        # Apply unique material with hue shift
        hue = i / variations
        mat = bpy.data.materials.new(name=f"Icon_Mat_{i}")
        mat.use_nodes = True
        bsdf = mat.node_tree.nodes["Principled BSDF"]

        # HSV to RGB conversion (simplified)
        import colorsys
        r, g, b = colorsys.hsv_to_rgb(hue, 0.7, 0.9)
        bsdf.inputs["Base Color"].default_value = (r, g, b, 1)

        obj.data.materials.append(mat)
        assets.append(obj)

    return assets

# Generate 5 sphere icon variations
icons = generate_icon_set('sphere', 5)

MCP Tool Reference

When Blender MCP is connected, use these tools:

Scene Information

code

get_scene_info - Returns objects, materials, cameras in scene
get_object_info(name) - Get details about specific object

Object Operations

code

create_object(type, name, location) - Create primitive
modify_object(name, location, rotation, scale) - Transform object
delete_object(name) - Remove object

Materials

code

set_material(object_name, color, metallic, roughness) - Quick material

Code Execution

code

execute_blender_code(code) - Run Python in Blender context

External Assets

code

get_polyhaven_assets(type) - List Poly Haven HDRIs/textures/models
download_polyhaven_asset(name, type) - Download asset
search_sketchfab(query) - Search 3D models
import_sketchfab_model(url) - Import from Sketchfab
generate_hyper3d_model(prompt) - AI-generate 3D model

Viewport

code

get_screenshot - Capture current viewport

Export Checklist for StickerNest

Before exporting an asset for StickerNest:

• Triangle count under target (widgets: 10k, environments: 50k)
• All modifiers applied
• Materials use Principled BSDF (GLTF-compatible)
• UV coordinates present for textured objects
• Object origins centered appropriately
• Scale applied (Ctrl+A > Scale)
• No duplicate vertices (Mesh > Clean Up > Merge by Distance)
• Named appropriately (sn-{category}-{name})
• Export with Y-up for Three.js compatibility

Troubleshooting

Issue: MCP not connecting

Cause: Blender addon not enabled or connection refused Fix: Check addon is enabled, ensure port 9876 is free, restart Blender

Issue: Export has wrong orientation

Cause: Blender uses Z-up, Three.js uses Y-up Fix: Enable export_yup=True in GLTF export settings

Issue: Materials look different in Three.js

Cause: Blender materials may use features not in GLTF spec Fix: Stick to Principled BSDF with basic inputs only

Issue: Model too large/heavy

Cause: High poly count or large textures Fix: Use Decimate modifier, reduce texture resolution

Reference Files

•Agent definition: .claude/agents/blender-3d-creation.md
•MCP configuration: .claude/mcp.json
•3D asset folder: public/assets/3d/
•Widget models: src/widgets/builtin/*/assets/

Additional Resources

•Blender Python API Docs
•Blender MCP GitHub
•GLTF Specification
•Poly Haven - Free HDRIs, textures, models