.. _recon:

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> **_RECON_**

>

>> This command flips connections in the mesh to get restore the Delaunay
criterion or to improve element shapes. The option 1 (recommended for 2D
meshes only) adds points on the boundaries if needed. The option 0 (default)
specifies that no points are to be added on the boundaries. The standard
method used by recon is to flip connections based on the in-sphere test (the
circumsphere of a tetrahedral element should contain no other nodes).
Additional flipping criteria are available. The Minimum Error Gradient
Adaption ([mega](RADAPT.html)) can be invoked by changing the value of the
code variable [ivoronoi](../meshobject.html) (**cmo/setatt**//ivoronoi/-2).
The effect of this option is to generate well shaped elements; however the
grid will not be Delaunay. If the user has a function to used for adaptive
reconnection this option is available by setting the code variable ivoronoi to
2 (**cmo/setatt**//ivoronoi/2). The user will have to supply an external
function.

> > If damage is specified then flips on exterior boundaries are checked to
verify that the maximum depth of deformation of the external boundary does not
exceed the value of damage. The default value of damage is 1% of the problem
size. This setting prevents connecting across corners if the external boundary
is a reflective box.

>>

>> If the keyword **checkaxy **is provided, then 2D flips are suppressed if
the new triangles

would have xy-projected areas less than EPSILONA.

>>

>> **recon** is called by other LaGriT commands such as
**massage**.&nbsp_place_holder; To disable recon set ivoronoi to 5
(**cmo/setatt**//ivoronoi/5).

>>

>> **recon** will by default reconnect across interface
edges.&nbsp_place_holder; To restrict reconnection to interior faces and
exterior boundary faces, set [iopt2to2](../meshobject.html) to 0
(**cmo/setatt**//iopt2to2/0)

>

> FORMAT:

>

>> **recon**/[**1**|**0**]/[damage]/[**checkaxy**]

>

> EXAMPLES:

>

>> **recon**&nbsp_place_holder;&nbsp_place_holder; attempt to restore Delaunay

>>

>> **cmo/setatt**//ivoronoi/-2

>>

>> **recon&nbsp_place_holder;**&nbsp_place_holder;&nbsp_place_holder; attempt
to improve geometric mesh quality

>>

>> **recon**/**1**&nbsp_place_holder; for 2d meshes add nodes on boundaries to
guarantee Delaunay

>>

>> **recon**//.001&nbsp_place_holder; reconnect limit interface and boundary
damage to a maximum of .001.

>>

>> **recon**/0/.001/**checkaxy**&nbsp_place_holder; for 2d meshes reconnect,
limiting damage to a maximum of .001

&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&n
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p_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_
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ace_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_plac
e_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_
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er;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder
;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder; and preventing
creation of any negatively oriented or small triangles

&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&n
bsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbs
p_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_
place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_pl
ace_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_plac
e_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_
holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_ho
lder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_hold
er;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder
;&nbsp_place_holder;&nbsp_place_holder;&nbsp_place_holder; (with respect to
the xy-plane).

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>

> [Click here for demos](../demos/2d_recon/test/html/main_2d_recon.html)

>

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