blender-3d-modeling

Blender 3D Modeling

Overview

Create 3D geometry procedurally using Blender's Python API. Build meshes from vertices and faces, use bmesh for advanced editing, apply modifiers, generate curves, and create parametric or procedural models entirely from code.

Instructions

1. Create a mesh from raw vertex data

import bpy

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

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")