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\page import_algos_page Use Existing Elements Algorithms

\n <em>Use Existing Elements </em>algorithms allow to define the mesh of a geometrical
object by the importing suitably located mesh elements from another
mesh. The mesh elements to import from the other mesh are to be contained in
groups. If several groups are used to mesh one geometry, validity of
nodal connectivity of result mesh must be assured by connectivity of
the source mesh; no geometrical checks are performed to merge
different nodes at same locations.
<br> The source elements must totally cover the meshed geometry.
The source elements lying partially over the geometry will not be used.
<br>
These algorithms can be used to mesh a very complex geometry part by
part, by storing meshes of parts in files and then fusing them
together using these algorithms.
<br>

<b>Use Existing 1D Elements</b> algorithm allows to define the mesh of
a geometrical edge (or group of edges)
by importing mesh edges contained in a group (or groups) from another mesh.
\n To apply this algorithm select the edge to be meshed (indicated in
the field \b Geometry of <b>Create mesh</b> dialog box),
<b>Use existing 1D elements</b> in the list of 1D algorithms and click the
<em>"Add Hypothesis"</em> button.
The following dialog box will appear:

\image html hyp_source_edges.png

In this dialog box you can define 
<ul>
<li>The \b Name of the algorithm. </li>
<li>The <b>Groups of Edges</b> to import 1D elements from.
<li>The <b>To copy mesh</b> checkbox is to import not only the edges of
the selected <b>Groups of Edges</b> but to copy the whole source
mesh. In this case <b>To copy groups</b>, if checked, forces creating
the same groups as in the imported source mesh.</li>
</ul>

<b>Use Existing 2D Elements</b> algorithm allows to define the mesh of
a geometrical face (or group of faces)
by importing mesh faces contained in a group (or groups) from another mesh.
\n To apply this algorithm select the geometrical face to be meshed (indicated in
the field \b Geometry of <b>Create mesh</b> dialog box),
<b>Use existing 2D elements</b> in the list of 2D algorithms and click the
<em>"Add Hypothesis"</em> button.
The following dialog box will appear:

\image html hyp_source_faces.png

In this dialog box you can define 
<ul>
<li>The \b Name of the algorithm. </li>
<li>The <b>Groups of Faces</b> to import 2D elements from.
<li>The <b>To copy mesh</b> checkbox is to import not only the faces of
the selected <b>Groups of Faces</b> but to copy the whole source
mesh. In this case <b>To copy groups</b>, if checked, forces creating
the same groups as in the imported source mesh.</li>
</ul>

<br><b>See Also</b> a sample TUI Script of a 
\ref tui_import "Use Existing Elements Algorithms".

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