vertices = [ (-1, -1, 0), (1, -1, 0), (1, 1, 0), (-1, 1, 0), # bottom (-1, -1, 2), (1, -1, 2), (1, 1, 2), (-1, 1, 2), # top ] faces = [ (0, 1, 2, 3), # bottom (4, 5, 6, 7), # top (0, 1, 5, 4), # front (2, 3, 7, 6), # back (0, 3, 7, 4), # left (1, 2, 6, 5), # right ]

mesh = bpy.data.meshes.new("CustomBox") mesh.from_pydata(vertices, [], faces) mesh.update()

obj = bpy.data.objects.new("CustomBox", mesh) bpy.context.collection.objects.link(obj)


`from_pydata(vertices, edges, faces)` is the primary way to build meshes. Pass empty lists `[]` for edges or faces if not needed.

### 2. Use bmesh for advanced mesh editing

```python
import bpy
import bmesh

# Create from scratch
bm = bmesh.new()

# Or edit an existing mesh
obj = bpy.context.active_object
bm = bmesh.new()
bm.from_mesh(obj.data)

# Add geometry
v1 = bm.verts.new((0, 0, 0))
v2 = bm.verts.new((1, 0, 0))
v3 = bm.verts.new((1, 1, 0))
v4 = bm.verts.new((0, 1, 0))
bm.faces.new((v1, v2, v3, v4))

# Common operations
bmesh.ops.extrude_face_region(bm, geom=bm.faces[:])
bmesh.ops.translate(bm, vec=(0, 0, 1), verts=[v for v in bm.verts if v.select])
bmesh.ops.subdivide_edges(bm, edges=bm.edges[:], cuts=2)

# Write back to mesh
bm.to_mesh(obj.data)
bm.free()
obj.data.update()

Always call bm.free() when done to release memory.

3. Apply modifiers programmatically

import bpy

obj = bpy.context.active_object

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

# Mirror
mirror = obj.modifiers.new(name="Mirror", type='MIRROR')
mirror.use_axis = (True, False, False)
mirror.use_clip = True

# Array
array = obj.modifiers.new(name="Array", type='ARRAY')
array.count = 5
array.relative_offset_displace = (1.1, 0, 0)

# Boolean
bool_mod = obj.modifiers.new(name="Boolean", type='BOOLEAN')
bool_mod.operation = 'DIFFERENCE'
bool_mod.object = bpy.data.objects["Cutter"]

# Solidify
solid = obj.modifiers.new(name="Solidify", type='SOLIDIFY')
solid.thickness = 0.1

# Bevel
bevel = obj.modifiers.new(name="Bevel", type='BEVEL')
bevel.width = 0.05
bevel.segments = 3

# Apply a modifier permanently
bpy.context.view_layer.objects.active = obj
bpy.ops.object.modifier_apply(modifier="Subdivision")

4. Create curves and surfaces

import bpy
import math

# Create a bezier curve
curve_data = bpy.data.curves.new("MyCurve", type='CURVE')
curve_data.dimensions = '3D'
curve_data.resolution_u = 24

spline = curve_data.splines.new('BEZIER')
spline.bezier_points.add(3)  # 4 points total (1 default + 3 added)

coords = [(0, 0, 0), (1, 1, 0), (2, 0, 1), (3, 1, 1)]
for i, (x, y, z) in enumerate(coords):
    pt = spline.bezier_points[i]
    pt.co = (x, y, z)
    pt.handle_type_left = 'AUTO'
    pt.handle_type_right = 'AUTO'

# Add depth to make it a tube
curve_data.bevel_depth = 0.1
curve_data.bevel_resolution = 4

obj = bpy.data.objects.new("MyCurve", curve_data)
bpy.context.collection.objects.link(obj)

# Create a NURBS circle
bpy.ops.curve.primitive_nurbs_circle_add(radius=2)
circle = bpy.context.active_object
circle.data.bevel_depth = 0.05

5. Procedural generation patterns

Grid of objects:

import bpy

rows, cols = 10, 10
spacing = 2.5

for i in range(rows):
    for j in range(cols):
        bpy.ops.mesh.primitive_cube_add(
            size=1,
            location=(i * spacing, j * spacing, 0)
        )
        obj = bpy.context.active_object
        obj.name = f"Grid_{i}_{j}"

Circular array:

import bpy
import math

count = 12
radius = 5

for i in range(count):
    angle = (2 * math.pi * i) / count
    x = radius * math.cos(angle)
    y = radius * math.sin(angle)
    bpy.ops.mesh.primitive_cylinder_add(radius=0.3, depth=2, location=(x, y, 0))
    obj = bpy.context.active_object
    obj.rotation_euler.z = angle

Terrain from heightmap:

import bpy
import bmesh
import math
import random

size = 20
res = 50

bm = bmesh.new()
verts = []
for i in range(res):
    row = []
    for j in range(res):
        x = (i / res - 0.5) * size
        y = (j / res - 0.5) * size
        z = math.sin(x * 0.5) * math.cos(y * 0.5) * 2 + random.uniform(-0.2, 0.2)
        row.append(bm.verts.new((x, y, z)))
    verts.append(row)

for i in range(res - 1):
    for j in range(res - 1):
        bm.faces.new((verts[i][j], verts[i+1][j], verts[i+1][j+1], verts[i][j+1]))

mesh = bpy.data.meshes.new("Terrain")
bm.to_mesh(mesh)
bm.free()

obj = bpy.data.objects.new("Terrain", mesh)
bpy.context.collection.objects.link(obj)

# Smooth the terrain
sub = obj.modifiers.new("Smooth", 'SUBSURF')
sub.levels = 1

6. Assign materials to faces

import bpy
import bmesh

obj = bpy.context.active_object

# Create materials
mat_red = bpy.data.materials.new("Red")
mat_red.diffuse_color = (1, 0, 0, 1)
mat_blue = bpy.data.materials.new("Blue")
mat_blue.diffuse_color = (0, 0, 1, 1)

obj.data.materials.append(mat_red)   # index 0
obj.data.materials.append(mat_blue)  # index 1

# Assign by face index
for i, poly in enumerate(obj.data.polygons):
    poly.material_index = 0 if i % 2 == 0 else 1

Examples

Example 1: Parametric staircase

User request: "Generate a spiral staircase with 20 steps"

import bpy
import math

def create_spiral_staircase(steps=20, radius=3, height=6, step_width=1.5):
    bpy.ops.object.select_all(action='SELECT')
    bpy.ops.object.delete()

    step_height = height / steps
    angle_per_step = (2 * math.pi) / steps

    for i in range(steps):
        angle = i * angle_per_step
        x = radius * math.cos(angle)
        y = radius * math.sin(angle)
        z = i * step_height

        bpy.ops.mesh.primitive_cube_add(
            size=1,
            location=(x, y, z),
            scale=(step_width, 0.4, step_height * 0.8)
        )
        step = bpy.context.active_object
        step.rotation_euler.z = angle
        step.name = f"Step_{i+1:02d}"

    # Add central column
    bpy.ops.mesh.primitive_cylinder_add(
        radius=0.2, depth=height, location=(0, 0, height / 2)
    )
    bpy.context.active_object.name = "CentralColumn"

create_spiral_staircase(steps=20)
bpy.ops.wm.save_as_mainfile(filepath="/tmp/staircase.blend")

Example 2: Honeycomb panel

User request: "Create a flat honeycomb pattern panel"

import bpy
import bmesh
import math

def create_hexagon(bm, cx, cy, radius):
    verts = []
    for i in range(6):
        angle = math.radians(60 * i + 30)
        x = cx + radius * math.cos(angle)
        y = cy + radius * math.sin(angle)
        verts.append(bm.verts.new((x, y, 0)))
    bm.faces.new(verts)

radius = 0.5
rows, cols = 8, 10
bm = bmesh.new()

for row in range(rows):
    for col in range(cols):
        cx = col * radius * 1.75
        cy = row * radius * 1.52
        if col % 2 == 1:
            cy += radius * 0.76
        create_hexagon(bm, cx, cy, radius * 0.9)

mesh = bpy.data.meshes.new("Honeycomb")
bm.to_mesh(mesh)
bm.free()

obj = bpy.data.objects.new("Honeycomb", mesh)
bpy.context.collection.objects.link(obj)

# Add thickness
solid = obj.modifiers.new("Solidify", 'SOLIDIFY')
solid.thickness = 0.1

Guidelines

Use from_pydata() for simple static meshes. Use bmesh when you need to build geometry with operations like extrude, subdivide, or per-face manipulation.
Always call mesh.update() after from_pydata() and bm.free() after bmesh operations.
When applying modifiers via bpy.ops.object.modifier_apply(), ensure the object is active and selected.
For large procedural meshes (10k+ faces), prefer bmesh over repeated bpy.ops calls — it's significantly faster since operators have per-call overhead.
Link new objects to a collection with bpy.context.collection.objects.link(obj) — objects not linked to any collection won't appear in the scene.
Blender uses Z-up coordinate system. Keep this in mind when importing from Y-up systems (most game engines).
For smooth shading: bpy.ops.object.shade_smooth() or set per-face polygon.use_smooth = True.
Test procedural scripts with small counts first, then scale up. A 100x100 grid with subdivision modifiers can freeze Blender.

blender-3d-modeling

Blender 3D Modeling

Overview

Instructions

1. Create a mesh from raw vertex data