"""
Read a FreeCAD document
=======================

``.FCStd`` is FreeCAD's native document format: a zip archive carrying
``Document.xml`` plus one BREP per part. ``pyvista_cad.read_fcstd``
parses the manifest and tessellates the BREPs via OCP, no FreeCAD
binary required.

This example reads a real part straight from the FreeCAD parts library
(CC-BY 3.0, FreeCAD-library contributors): an M3 nyloc lock nut, and
walks the resulting :class:`pyvista.MultiBlock`.

Why this matters: FreeCAD is the dominant open-source MCAD package.
Reading FCStd without a FreeCAD install lets analysis pipelines pick
up community parts directly.
"""

# %%

import pyvista as pv

import pyvista_cad
from pyvista_cad.examples import downloads

# %%
# Read the real FCStd document.

mb = pyvista_cad.read_fcstd(downloads.fcstd_nut_path())
mb

# %%
# Render the nut.

for _, part in mb.cad.walk():
    part['elevation'] = part.points[:, 2]

pl = pv.Plotter()
pl.cad.add(mb, scalars='elevation', cmap='cividis')
pl.show()