"""Bridges to and from build123d.
Translates between :mod:`build123d` shapes / compounds and PyVista
datasets, riding on the shared OCCT tessellator in
:mod:`pyvista_cad._conversion`.
"""
from collections.abc import Iterable
from typing import Any
import numpy as np
import pyvista as pv
from pyvista_cad._conversion import (
polydata_to_topods,
topods_to_polydata,
unwrap_to_topods,
)
from pyvista_cad._errors import OptionalDependencyError
def _color_rgb(obj: Any) -> tuple[float, ...] | None:
"""Extract an RGB or RGBA color from a build123d object.
A modern :class:`build123d.Color` is iterable, yielding four
floats ``(r, g, b, a)`` in ``[0, 1]``; it exposes neither
``.r/.g/.b`` attributes nor item access. Legacy color objects
carrying ``.r/.g/.b`` are still handled for forward compatibility.
Parameters
----------
obj : Any
build123d shape or compound child. Its ``color`` attribute
is read; anything else is ignored.
Returns
-------
tuple of float or None
``(r, g, b)`` or ``(r, g, b, a)`` in ``[0, 1]``, matching the
``cad.color`` contract. ``None`` when no usable color exists.
"""
color = getattr(obj, 'color', None)
if color is None:
return None
r = getattr(color, 'r', None)
g = getattr(color, 'g', None)
b = getattr(color, 'b', None)
if r is not None and g is not None and b is not None:
try:
return (float(r), float(g), float(b))
except (TypeError, ValueError):
return None
if isinstance(color, Iterable) and not isinstance(color, (str, bytes)):
try:
components = [float(c) for c in color]
except (TypeError, ValueError):
return None
if len(components) >= 4:
return tuple(components[:4])
if len(components) == 3:
return tuple(components[:3])
return None
return None
[docs]
def from_build123d(
shape: Any,
/,
*,
linear_deflection: float = 0.1,
angular_deflection: float = 0.5,
pass_data: bool = True,
) -> pv.PolyData | pv.MultiBlock:
"""Convert a :mod:`build123d` ``Shape`` or ``Compound`` to PyVista.
Parameters
----------
shape : build123d.Shape or build123d.Compound
Input geometry.
linear_deflection : float, default: 0.1
OCCT tessellation linear deflection (model units).
angular_deflection : float, default: 0.5
OCCT tessellation angular deflection (radians).
pass_data : bool, default: True
When ``True``, propagate build123d color and label onto
``cad.color`` and ``cad.label`` field-data.
Returns
-------
pyvista.PolyData or pyvista.MultiBlock
``PolyData`` for a single shape; ``MultiBlock`` for a
``Compound`` with multiple children.
Raises
------
pyvista_cad.OptionalDependencyError
If :mod:`build123d` is not installed.
Examples
--------
Convert a build123d box to PyVista (requires the ``[step]`` extra):
>>> import build123d as b3d
>>> from pyvista_cad import from_build123d
>>> box = b3d.Box(10, 10, 10)
>>> mesh = from_build123d(box)
>>> type(mesh).__name__
'PolyData'
>>> [round(b) for b in mesh.bounds]
[-5, 5, -5, 5, -5, 5]
"""
try:
import build123d as b3d
except ImportError as exc:
msg = 'build123d not installed; install pyvista-cad[step]'
raise OptionalDependencyError(msg) from exc
if isinstance(shape, b3d.Compound):
children = list(shape.children) if getattr(shape, 'children', None) else []
if children:
mb = pv.MultiBlock()
for child in children:
topods = unwrap_to_topods(child)
poly = topods_to_polydata(
topods,
linear_deflection=linear_deflection,
angular_deflection=angular_deflection,
)
label = getattr(child, 'label', '') or f'part_{mb.n_blocks}'
if pass_data:
color = _color_rgb(child)
if color is not None:
poly.field_data['cad.color'] = np.asarray(color, dtype=float)
poly.field_data['cad.label'] = np.array([label])
poly.field_data['cad.source_format'] = np.array(['build123d'])
mb.append(poly, name=label)
mb.field_data['cad.source_format'] = np.array(['build123d'])
return mb
topods = unwrap_to_topods(shape)
poly = topods_to_polydata(
topods,
linear_deflection=linear_deflection,
angular_deflection=angular_deflection,
)
if pass_data:
color = _color_rgb(shape)
if color is not None:
poly.field_data['cad.color'] = np.asarray(color, dtype=float)
label = getattr(shape, 'label', '') or ''
if label:
poly.field_data['cad.label'] = np.array([label])
poly.field_data['cad.source_format'] = np.array(['build123d'])
return poly
[docs]
def to_build123d(mesh: pv.PolyData) -> Any:
"""Wrap a :class:`pyvista.PolyData` as a faceted ``build123d.Compound``.
Parameters
----------
mesh : pyvista.PolyData
Surface mesh to convert.
Returns
-------
build123d.Compound
Faceted compound. Analytical surface data is lost; chained
fillets / shells will not behave as on parametric geometry.
Raises
------
pyvista_cad.OptionalDependencyError
If :mod:`build123d` is not installed.
Examples
--------
Wrap a PyVista sphere as a build123d compound (requires the
``[step]`` extra):
>>> import pyvista as pv
>>> from pyvista_cad import to_build123d
>>> compound = to_build123d(pv.Sphere())
>>> type(compound).__name__
'Compound'
"""
try:
import build123d as b3d
except ImportError as exc:
msg = 'build123d not installed; install pyvista-cad[step]'
raise OptionalDependencyError(msg) from exc
topods = polydata_to_topods(mesh)
return b3d.Compound(topods)
