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

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_examples_trifaces.py>`
        to download the full example code.

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

.. _sphx_glr_examples_trifaces.py:


Face Markers and Surface Data
-----------------------------

Demonstrate the usage of several attributes of :class:`tetgen.TetGen`.

You can access faces and edges from an instance of :class:`tetgen.TetGen` from
the :attr:`tetgen.TetGen.trifaces` and :attr:`tetgen.TetGen.edges` attributes.

.. GENERATED FROM PYTHON SOURCE LINES 11-17

.. code-block:: Python


    # sphinx_gallery_thumbnail_number = 1
    import numpy as np
    import pyvista as pv
    import tetgen








.. GENERATED FROM PYTHON SOURCE LINES 18-19

First, let's tetrahedralize a sphere.

.. GENERATED FROM PYTHON SOURCE LINES 19-25

.. code-block:: Python


    sphere = pv.Icosphere(nsub=1)
    tet = tetgen.TetGen(sphere)
    tet.tetrahedralize(order=1, mindihedral=20, minratio=1.5, regionattrib=True)
    tet.grid






.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">

    <table style='width: 100%;'>
    <tr><th>UnstructuredGrid</th><th>Information</th></tr>
    <tr><td>N Cells</td><td>80</td></tr>
    <tr><td>N Points</td><td>43</td></tr>
    <tr><td>X Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Y Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Z Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>N Arrays</td><td>0</td></tr>
    </table>


    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 26-28

Next, let's construct a :class:`pyvista.PolyData` from the triangular faces,
accessible from the :attr:`tetgen.TetGen.trifaces` attribute.

.. GENERATED FROM PYTHON SOURCE LINES 28-34

.. code-block:: Python


    # mesh containing both exterior and interior elements
    trimesh = pv.PolyData.from_regular_faces(tet.node, tet.trifaces)
    trimesh







.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">

    <table style='width: 100%;'>
    <tr><th>PolyData</th><th>Information</th></tr>
    <tr><td>N Cells</td><td>200</td></tr>
    <tr><td>N Points</td><td>43</td></tr>
    <tr><td>N Strips</td><td>0</td></tr>
    <tr><td>X Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Y Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Z Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>N Arrays</td><td>0</td></tr>
    </table>


    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 35-37

Interior faces are marked by the :attr:`tetgen.TetGen.triface_markers` attribute.
We can plot this using PyVista.

.. GENERATED FROM PYTHON SOURCE LINES 37-50

.. code-block:: Python


    pl = pv.Plotter()
    pl.add_mesh(
        trimesh.explode(0.3),
        scalars=tet.triface_markers,
        show_edges=True,
        show_scalar_bar=False,
    )
    pl.enable_ssao(radius=0.1)
    pl.enable_anti_aliasing("ssaa")
    pl.camera.zoom(1.5)
    pl.show()




.. image-sg:: /examples/images/sphx_glr_trifaces_001.png
   :alt: trifaces
   :srcset: /examples/images/sphx_glr_trifaces_001.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 51-53

Interior faces are denoted with 0 and exterior faces are marked as -1 within
the :attr:`tetgen.TetGen.triface_markers` array.

.. GENERATED FROM PYTHON SOURCE LINES 53-57

.. code-block:: Python


    tet.triface_markers






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

 .. code-block:: none


    array([ 0,  0,  0, -1,  0,  0,  0, -1,  0,  0,  0, -1,  0,  0,  0, -1,  0,
            0,  0, -1,  0,  0,  0, -1,  0,  0, -1, -1,  0,  0, -1,  0,  0, -1,
           -1,  0,  0, -1, -1,  0, -1,  0,  0, -1,  0,  0, -1,  0, -1,  0, -1,
            0,  0, -1,  0,  0, -1,  0,  0, -1,  0, -1,  0,  0, -1,  0, -1,  0,
            0,  0, -1,  0,  0, -1,  0, -1,  0, -1,  0,  0, -1,  0, -1,  0, -1,
            0,  0, -1,  0, -1,  0, -1,  0,  0, -1,  0,  0, -1,  0, -1,  0,  0,
           -1,  0,  0, -1,  0,  0, -1,  0, -1,  0,  0,  0, -1,  0,  0,  0, -1,
            0, -1,  0, -1,  0, -1,  0, -1,  0,  0, -1,  0,  0,  0, -1,  0, -1,
            0, -1,  0,  0, -1,  0,  0, -1, -1,  0,  0, -1,  0,  0, -1,  0, -1,
            0,  0,  0, -1, -1,  0,  0, -1,  0, -1,  0, -1,  0, -1,  0,  0, -1,
            0, -1, -1,  0,  0, -1,  0, -1,  0, -1,  0,  0, -1, -1,  0,  0, -1,
            0, -1, -1,  0, -1,  0, -1,  0, -1, -1,  0, -1, -1], dtype=int32)



.. GENERATED FROM PYTHON SOURCE LINES 58-60

Finally, create an edges :class:`pyvista.PolyData` from the
:attr:`tetgen.TetGen.edges` attribute.

.. GENERATED FROM PYTHON SOURCE LINES 60-74

.. code-block:: Python


    # construct a VTK style edges array
    n_edges = tet.edges.shape[0]
    edges = np.empty((n_edges, 3), dtype=int)
    edges[:, 0] = 2
    edges[:, 1:] = tet.edges

    # mesh containing both exterior and interior elements
    edgemesh = pv.PolyData()
    edgemesh.points = tet.node
    edgemesh.lines = edges
    edgemesh







.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">

    <table style='width: 100%;'>
    <tr><th>PolyData</th><th>Information</th></tr>
    <tr><td>N Cells</td><td>162</td></tr>
    <tr><td>N Points</td><td>43</td></tr>
    <tr><td>N Strips</td><td>0</td></tr>
    <tr><td>X Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Y Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>Z Bounds</td><td>-1.000e+00, 1.000e+00</td></tr>
    <tr><td>N Arrays</td><td>0</td></tr>
    </table>


    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 75-76

Plot the edges with ``pyvista`` and color the interior and exterior edges.

.. GENERATED FROM PYTHON SOURCE LINES 76-85

.. code-block:: Python


    edgemesh.plot(
        scalars=tet.edge_markers,
        cmap="bwr",
        line_width=10,
        render_lines_as_tubes=True,
        show_scalar_bar=False,
        zoom=1.5,
    )



.. image-sg:: /examples/images/sphx_glr_trifaces_002.png
   :alt: trifaces
   :srcset: /examples/images/sphx_glr_trifaces_002.png
   :class: sphx-glr-single-img






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

   **Total running time of the script:** (0 minutes 20.295 seconds)


.. _sphx_glr_download_examples_trifaces.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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