.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/pre-processing/example_build_mesh.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_gallery_pre-processing_example_build_mesh.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_pre-processing_example_build_mesh.py:


Building a model from a pyvista grid
====================================

When you don't have a CDB on disk, the easiest way to build a
:class:`femorph_solver.Model` from scratch is to author a
:class:`pyvista.UnstructuredGrid` directly and hand it to
:meth:`femorph_solver.Model.from_grid`.  Here we build a 4-element
HEX8 cantilever beam this way — no foreign deck required.

.. GENERATED FROM PYTHON SOURCE LINES 11-21

.. code-block:: Python


    from __future__ import annotations

    import numpy as np
    import pyvista as pv
    from vtkmodules.util.vtkConstants import VTK_HEXAHEDRON

    import femorph_solver
    from femorph_solver import ELEMENTS








.. GENERATED FROM PYTHON SOURCE LINES 22-24

Author the nodes
----------------

.. GENERATED FROM PYTHON SOURCE LINES 24-39

.. code-block:: Python

    LX, LY, LZ = 4.0, 1.0, 1.0
    NX = 4

    points: list[tuple[float, float, float]] = []
    node_id: dict[tuple[int, int, int], int] = {}
    nn = 0
    for i in range(NX + 1):
        for j in range(2):
            for k in range(2):
                points.append((i * LX / NX, j * LY, k * LZ))
                node_id[(i, j, k)] = nn  # 0-based pyvista index
                nn += 1

    points_arr = np.asarray(points, dtype=float)








.. GENERATED FROM PYTHON SOURCE LINES 40-42

Author the hex connectivity
---------------------------

.. GENERATED FROM PYTHON SOURCE LINES 42-61

.. code-block:: Python

    cells: list[int] = []
    for i in range(NX):
        cells.extend(
            [
                8,
                node_id[(i, 0, 0)],
                node_id[(i + 1, 0, 0)],
                node_id[(i + 1, 1, 0)],
                node_id[(i, 1, 0)],
                node_id[(i, 0, 1)],
                node_id[(i + 1, 0, 1)],
                node_id[(i + 1, 1, 1)],
                node_id[(i, 1, 1)],
            ]
        )

    cell_types = np.full(NX, VTK_HEXAHEDRON, dtype=np.uint8)
    grid = pv.UnstructuredGrid(np.asarray(cells), cell_types, points_arr)








.. GENERATED FROM PYTHON SOURCE LINES 62-64

Wrap as a Model and stamp material
----------------------------------

.. GENERATED FROM PYTHON SOURCE LINES 64-69

.. code-block:: Python

    m = femorph_solver.Model.from_grid(grid)
    m.assign(ELEMENTS.HEX8, material={"EX": 2.1e11, "PRXY": 0.30, "DENS": 7850.0})

    print(f"model: {m.n_nodes} nodes, {m.n_elements} elements")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    model: 20 nodes, 4 elements




.. GENERATED FROM PYTHON SOURCE LINES 70-72

Apply BCs and solve
-------------------

.. GENERATED FROM PYTHON SOURCE LINES 72-93

.. code-block:: Python

    node_nums = np.asarray(grid.point_data["ansys_node_num"])
    pts = np.asarray(grid.points)

    fixed = node_nums[pts[:, 0] < 1e-9]
    m.fix(nodes=fixed.tolist(), dof="ALL")

    tip_mask = pts[:, 0] > LX - 1e-9
    tip_nodes = node_nums[tip_mask]
    for tip_nn in tip_nodes:
        m.apply_force(int(tip_nn), fz=-250.0)

    res = m.solve()
    dof_map = m.dof_map()
    tip_uz = np.array(
        [
            res.displacement[int(np.where((dof_map[:, 0] == nn) & (dof_map[:, 1] == 2))[0][0])]
            for nn in tip_nodes
        ]
    )
    print(f"tip UZ (mean over 4 corner nodes): {tip_uz.mean():.4e} m")





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    tip UZ (mean over 4 corner nodes): -1.4761e-06 m




.. GENERATED FROM PYTHON SOURCE LINES 94-96

Render
------

.. GENERATED FROM PYTHON SOURCE LINES 96-110

.. code-block:: Python

    deformed = femorph_solver.io.static_result_to_grid(m, res)
    plotter = pv.Plotter(off_screen=True)
    plotter.add_mesh(deformed, style="wireframe", color="gray", opacity=0.35, label="undeformed")
    plotter.add_mesh(
        deformed.warp_by_vector("displacement", factor=500.0),
        scalars="displacement_magnitude",
        show_edges=True,
        cmap="viridis",
        scalar_bar_args={"title": "|u| [m]"},
        label="deformed (×500)",
    )
    plotter.add_legend()
    plotter.add_axes()
    plotter.show()



.. image-sg:: /gallery/pre-processing/images/sphx_glr_example_build_mesh_001.png
   :alt: example build mesh
   :srcset: /gallery/pre-processing/images/sphx_glr_example_build_mesh_001.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 1.112 seconds)


.. _sphx_glr_download_gallery_pre-processing_example_build_mesh.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: example_build_mesh.ipynb <example_build_mesh.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: example_build_mesh.py <example_build_mesh.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: example_build_mesh.zip <example_build_mesh.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_