.. _geometry:
.. include:: /icons.rst
========
Geometry
========
The Geometry pane is used to define the model geometry. This includes whether
the model is 2D or 3D, and the overall domain extents (xmin, xmax, ymin, ymax,
zmin, zmax). If there is complex geometry, the "Auto-size" button can
automatically set the extents to surround the geometry.
The geometry section provides tools for adding geometry objects (from STL files,
or primitive elements), filters to transform geometry objects, and
wizards to automate creating common complex geometries. Geometry objects can be
copied, removed, or combined using Boolean operations. All the geometry
operations are done using the `Visualization Toolkit (VTK)
`__'s library.
Geometry toolbar icons:
+----------------+-----------------------------------------------------+
| Icon | Description |
+================+=====================================================+
| |geometry| | Add geometry to model |
+----------------+-----------------------------------------------------+
| |filter| | Modify selected geometry with filter |
+----------------+-----------------------------------------------------+
| |wizard| | Add geometry from wizard |
+----------------+-----------------------------------------------------+
| |remove| | Remove the selected geometry |
+----------------+-----------------------------------------------------+
| |copy| | Add duplicate of the selected geometry (copy/paste) |
+----------------+-----------------------------------------------------+
| |union| | Add union of two or more selected geometries |
+----------------+-----------------------------------------------------+
| |intersect| | Add intersection of two or more selected geometries |
+----------------+-----------------------------------------------------+
| |difference| | Add difference of two or more selected geometries |
+----------------+-----------------------------------------------------+
In the geometry tree, the geometry object is displayed with the following icons:
+----------------+-----------------+
| Icon | Geometry Type |
+================+=================+
| |geometry| | polydata |
+----------------+-----------------+
| |function| | implicit |
+----------------+-----------------+
| |filter| | filter |
+----------------+-----------------+
| |union| | union |
+----------------+-----------------+
| |intersect| | intersect |
+----------------+-----------------+
| |difference| | difference |
+----------------+-----------------+
Adding Geometry
^^^^^^^^^^^^^^^
To add a Geometry object, click on the |geometry| (Geometry) icon and select
the geometry to add from the drop-down menu.
There are two types of geometric objects supported in the GUI: implicit
functions (quadrics), and objects defined by polydata (everything else: STL
files, primitives, parametrics, wizard geometry).
The following geometric objects can be added:
- STL files (select a \*.stl file from a file dialog)
- Implicit (Quadric) functions (sphere, box, cylinder, cone, quadric, superquadric)
- Primitives (sphere, box, cylinder, cone)
- Parametrics (torus, boy, conic spiral, etc.)
Applying Filters
^^^^^^^^^^^^^^^^
To apply a filter to the selected geometry, select a filter from the Filter
menu. The filter options can be edited in the parameter section. The following
filters are included:
+----------------------------+----------------------------------------------+------------------------------+
|Filter |Description |vtk class |
+============================+==============================================+==============================+
|sample implicit |converts an implicit function to polydata |vtkSampleFunction |
+----------------------------+----------------------------------------------+------------------------------+
|transform |rotate, scale, translate polydata |vtkTransformPolyDataFilter |
+----------------------------+----------------------------------------------+------------------------------+
|clean |merge duplicate points and remove unused |vtkCleanPolyData |
| |points and degenerate cells | |
+----------------------------+----------------------------------------------+------------------------------+
|fill holes |fill holes |vtkFillHolesFilter |
+----------------------------+----------------------------------------------+------------------------------+
|triangle |make sure all polys are triangles |vtkTriangleFilter |
+----------------------------+----------------------------------------------+------------------------------+
|decimate |reduce the number of triangles |vtkDecimatePro |
+----------------------------+----------------------------------------------+------------------------------+
|quadric decimation |reduce the number of triangles |vtkQuadricDecimation |
+----------------------------+----------------------------------------------+------------------------------+
|quadric clustering |reduce the number of triangles |vtkQuadricClustering |
+----------------------------+----------------------------------------------+------------------------------+
|linear subdivision |subdivide based on a linear scheme |vtkLinearSubdivisionFilter |
+----------------------------+----------------------------------------------+------------------------------+
|loop subdivision |subdivide based on the Loop scheme |vtkLoopSubdivisionFilter |
+----------------------------+----------------------------------------------+------------------------------+
|butterfly subdivision |subdivide based on 8-point butterfly scheme |vtkButterflySubdivisionFilter |
+----------------------------+----------------------------------------------+------------------------------+
|smooth |move points based on Laplacian smoothing |vtkSmoothPolyDataFilter |
+----------------------------+----------------------------------------------+------------------------------+
|windowed sinc |move points based on a windowed sinc function |vtkWindowedSincPolyDataFilter |
| |interpolation kernel | |
+----------------------------+----------------------------------------------+------------------------------+
|reverse sense |reverse order and/or normals of triangles |vtkReverseSense |
+----------------------------+----------------------------------------------+------------------------------+
Refer to the `VTK website `__ for details.
Wizards
^^^^^^^
Three wizards are available to more easily create common multiphase flow
geometries: cyclones, reactors, and hoppers. A special "distributed"
wizard is used to distribute one geometry inside another geometry with random,
cubic, or body centered cubic positions. Random rotations can also be applied
with the wizard.
|cyclone wizard| |hopper wizard| |reactor wizard|
Remove & Copy
^^^^^^^^^^^^^
To remove a selected geometry, click the |remove| (Remove) button. If a
geometry is grouped as part of a :ref:`boolean-operation`, removing it is
disabled until that Boolean Operation is removed first.
To duplicate the selected geometry, click the |copy| (Duplicate) button. If
multiple geometry objects are selected, duplication is disabled.
.. _boolean-operation:
Boolean Operation
^^^^^^^^^^^^^^^^^
There are two types of geometric objects supported in the GUI: implicit
functions (quadrics) and objects defined by polydata (everything else: STL
files, primitives, parametrics, wizard geometry). Boolean operations cannot be
performed between polydata and implicit geometry objects; the implicit function
needs to be converted to polydata by using the ``sample implicit`` filter.
Converting the implicit function also needs to be done in order for the GUI to
export a STL file that the mfixsolver can use.
Boolean operations can only be performed with geometry objects of the same
type (implicit, polydata). Boolean operations can not be performed
between polydata and implicit geometry objects. If an implicit and a polydata
must be managed together, the implicit object must be first converted to
a polydata object using the sample implicit filter.
.. note::
Boolean operation between two polydata objects is supported by MFiX, but for
complex objects the VTK library may crash.