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) can be invoked by changing the value of the code variable ivoronoi (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. To disable recon set ivoronoi to 5 (cmo/setatt//ivoronoi/5).

recon will by default reconnect across interface edges. To restrict reconnection to interior faces and exterior boundary faces, set iopt2to2 to 0 (cmo/setatt//iopt2to2/0)

FORMAT:

recon / [1 OR 0] / [damage] / [checkaxy]

EXAMPLES:

recon 

attempt to restore Delaunay

recon/1 

for 2d meshes add nodes on boundaries to guarantee Delaunay

recon//.001  

reconnect limit interface and boundary damage to a maximum of .001.

recon/0/.001/checkaxy  

for 2d meshes reconnect, limiting damage to a maximum of .001 and preventing creation of any negatively oriented or small triangles (with respect to the xy-plane).