ScadPy 0.4.3

Simplified 2D/3D modeling for Python with fluent API and boolean operations

ScadPy

Programmatic CAD in Pure Python. — Documentation

ScadPy provides a fluent, type-safe API for 2D and 3D parametric modeling, built on Shapely and trimesh. Write designs with the conciseness of OpenSCAD and the full power of Python.

Installation

pip install scadpy

Requirements: Python ≥ 3.12.

Quick examples

# 2D — chamfered mounting plate
from scadpy import rectangle, circle, text
import numpy as np

PLATE_WIDTH   = 80
PLATE_HEIGHT  = 50
PLATE_THICKNESS = 10
HOLE_RADIUS   = 4
HOLE_MARGIN   = 10
CHAMFER_SIZE  = 8

base  = rectangle([PLATE_WIDTH, PLATE_HEIGHT])
plate = base.chamfer(CHAMFER_SIZE)

for position, normal in zip(base.vertex_coordinates, base.vertex_normals):
    hole_center = position - HOLE_MARGIN * np.sqrt(2) * normal
    plate -= circle(HOLE_RADIUS).translate(hole_center)

plate.to_screen()

# 3D — extruded mounting plate with label (continues from above)
TEXT_THICKNESS = 2

extruded_plate = plate.linear_extrude(PLATE_THICKNESS)
label = text("ScadPy", size=15).linear_extrude(TEXT_THICKNESS)
extruded_plate |= label.translate(z(PLATE_THICKNESS))
extruded_plate.to_screen()

# 3D — parametric ball bearing
from scadpy import circle, rectangle, sphere, x, y, GRAY, ORANGE

BALL_RADIUS    = 3
RACE_RADIUS    = 15
NB_BALLS       = 11
CLEARANCE      = 0.1
RING_HEIGHT    = 7
RACE_THICKNESS = 10

groove  = circle(BALL_RADIUS + CLEARANCE) | rectangle([BALL_RADIUS, RING_HEIGHT])
race    = rectangle([RACE_THICKNESS, RING_HEIGHT]) - groove
bearing = race.radial_extrude(axis=y(), pivot=x(RACE_RADIUS)).color(GRAY)
ball    = sphere(BALL_RADIUS).color(ORANGE)
bearing += ball.radial_pattern(count=NB_BALLS, axis=y(), pivot=x(RACE_RADIUS))

bearing.to_screen()

# 3D — dice
from scadpy import cuboid, sphere, x, y, z

SIZE = 20
dice = cuboid(SIZE)
pip  = sphere(SIZE / 12).translate(z(SIZE / 2))

one   = pip
two   = pip.translate([SIZE / 4, SIZE / 4, 0]) + pip.translate([-SIZE / 4, -SIZE / 4, 0])
three = one + two
four  = two + two.rotate(90, z())
five  = one + four
six   = four + pip.translate(x(SIZE / 4)) + pip.translate(x(-SIZE / 4))

dice -= (
    one
    + two.rotate(90, x())
    + three.rotate(90, y())
    + four.rotate(-90, y())
    + five.rotate(-90, x())
    + six.rotate(-180, x())
)

dice.to_screen()

# 3D — storage box
from scadpy import square, x, z

SIZE_OUTER      = 20
SIZE_INNER      = 18
FILLET          = 1
BASE_HEIGHT     = 10
CUT_HEIGHT      = 8
CAP_HEIGHT_OUTER = 1.5
CAP_HEIGHT_INNER = 3
CAP_OFFSET_X    = 25
CUT_OFFSET_Z    = 2

outer_base = square(SIZE_OUTER).fillet(FILLET).linear_extrude(BASE_HEIGHT)
inner_cut  = square(SIZE_INNER).linear_extrude(CUT_HEIGHT).translate(z(CUT_OFFSET_Z))
base       = outer_base - inner_cut

cap_outer = square(SIZE_OUTER).fillet(FILLET).linear_extrude(CAP_HEIGHT_OUTER)
cap_inner = square(SIZE_INNER).linear_extrude(CAP_HEIGHT_INNER)
cap       = (cap_outer | cap_inner).translate(x(CAP_OFFSET_X))

storage_box = base + cap
storage_box.to_screen()

Cheat sheet

Parameters shown in # comments are optional, with their default values.

2D — Shape

from scadpy import *

# primitives
circle(radius=3)                                # segment_count=64
polygon(points=[(-2, -2), (2, -2), (0, 2)])
rectangle(size=[6, 3])
Shape.from_dxf("file.dxf")
Shape.from_svg("file.svg")
square(size=4)

# boolean operations
s = square(size=4);  c = circle(radius=3)
s | c    # union
s - c    # difference
s & c    # intersection
s ^ c    # symmetric difference
s + c    # concat (no merge)

# transforms
s.chamfer(size=0.8)              # vertex_filter=None, epsilon=1e-8
s.color(color=RED)
s.convexify()                    # part_filter=None
s.fill()                         # part_filter=None
s.fillet(size=0.8)               # vertex_filter=None, segment_count=32, epsilon=1e-8
s.grow(distance=0.5)             # part_filter=None
s.linear_cut(axis=x())          # pivot=0
s.linear_pattern(counts=4, steps=x(3))        # counts=[nx, ny], steps=[sx, sy]
s.linear_slice(thickness=2, direction=x())  # pivot=0, part_filter=None
s.mirror(normal=[1, 0])          # pivot=0
s.pull(distance=1.0)             # pivot=0, vertex_filter=None
s.push(distance=1.0)             # pivot=0, vertex_filter=None
s.radial_pattern(count=6)        # angle=360, pivot=0
s.radial_slice(start=0, end=180) # pivot=0, part_filter=None
s.resize(size=[6, None])         # auto=False, pivot=None, vertex_filter=None
s.rotate(angle=30)               # pivot=0, vertex_filter=None
s.scale(scale=[2, 0.5])          # pivot=0, vertex_filter=None
s.shrink(distance=0.5)           # part_filter=None
s.translate(translation=[2, 1])  # vertex_filter=None

# features
s.bounds                         # [min_x, min_y, max_x, max_y]
s.bounding_box                   # → Shape (rectangle)
s.centroid                       # [cx, cy] — geometric centroid
s.is_empty                       # bool

# topology — coordinates & attributes
s.are_vertices_convex            # (n_vertices,)   — convexity mask
s.directed_edge_directions       # (2*n_edges, 2)
s.edge_lengths                   # (n_edges,)
s.edge_midpoints                 # (n_edges,  2)
s.edge_normals                   # (n_edges,  2)
s.ring_types                     # (n_rings,)  — "exterior"|"interior"
s.vertex_angles                  # (n_vertices,)   — interior angles (°)
s.vertex_coordinates             # (n_vertices, 2)
s.vertex_normals                 # (n_vertices, 2) — outward unit normals

# topology — bridges (*_to_*)
s.directed_edge_to_edge             # directed_edge → edge
s.directed_edge_to_vertex           # directed_edge → [start, end]
s.edge_to_vertex                    # edge          → [start, end]
s.ring_to_part                      # ring          → part
s.vertex_to_incoming_directed_edge  # vertex        → directed_edge
s.vertex_to_outgoing_directed_edge  # vertex        → directed_edge
s.vertex_to_neighbor_vertex       # vertex        → [prev, next]
s.vertex_to_part                    # vertex        → part
s.vertex_to_ring                    # vertex        → ring

# extrusions → Solid
s.linear_extrude(height=3)
s.radial_extrude(axis=y(), pivot=x(5))  # start=0, end=360, segment_count=64

# export
s.to_dxf_file("output.dxf")
s.to_html_file("output.html")
s.to_screen()
s.to_svg_file("output.svg")

3D — Solid

from scadpy import *

# primitives
cone(radius=2, height=4)         # section_count=32
cuboid(size=[4, 3, 2])
cylinder(radius=2, height=4)     # section_count=32
polyhedron(vertices=vertices, faces=faces)
sphere(radius=3)                 # subdivision_count=4
Solid.from_stl("model.stl")

# boolean operations
a = cuboid(size=[4, 3, 2]);  b = sphere(radius=2)
a | b    # union
a - b    # difference
a & b    # intersection
a ^ b    # symmetric difference
a + b    # concat (no merge)

# transforms
a.color(color=RED)
a.convexify()                    # part_filter=None
a.linear_pattern(counts=4, steps=x(3))        # counts=[nx, ny, nz], steps=[sx, sy, sz]
a.mirror(normal=[1, 0, 0])       # pivot=0
a.pull(distance=1.0)             # pivot=0, vertex_filter=None
a.push(distance=1.0)             # pivot=0, vertex_filter=None
a.radial_pattern(count=6, axis=z())            # angle=360, pivot=0
a.resize(size=[6, None, None])   # auto=False, pivot=None, vertex_filter=None
a.rotate(angle=30, axis=z())    # pivot=0, vertex_filter=None
a.scale(scale=[2, 1, 0.5])       # pivot=0, vertex_filter=None
a.translate(translation=[1, 0, 0])  # vertex_filter=None

# features
a.bounds                         # [min_x, min_y, min_z, max_x, max_y, max_z]
a.bounding_box                   # → Solid (cuboid)
a.centroid                       # [cx, cy, cz] — geometric centroid
a.is_empty                       # bool

# topology — coordinates & bridges (*_to_*)
a.triangle_to_vertex    # triangle → [v0, v1, v2]
a.vertex_coordinates    # (n_vertices,  3)
a.vertex_to_part        # vertex   → part

# export
a.to_html_file("output.html")
a.to_screen()
a.to_stl_file("output.stl")

Roadmap

• Improve documentation
• Richer topology for Shape and Solid
• Richer transformations for Shape and Solid
• Chamfer and fillet on Solid
• New assembly types: PointCloud2d, Wire2d, PointCloud3d, Wire3d
• Better error messages
• More import/export formats

Development

# Create and activate venv
python3 -m venv .venv
source .venv/bin/activate

# Install with dev dependencies
pip install -e .[dev]

# Run doctests & generate documentation
cd docs && make doctest && make html

License

See LICENSE.md.