# Surfaces Replication

During the meshing process, open objects may be replicated in the meshing process to approximate them as two thin parallel layers. It may be useful to analyze open structures by using the CFIE formulation, as the thin layer replication allows to consider its objects at approximate volumes.

The following options may be edited within this section:

• Replicate Open Surfaces Select this option to activate the replication and the to enable rest of parameters in the window. If replication is enabled, the elements of the open objects are replicated to an automatic frequency-dependent distance from the original ones.
• Replication Area This section defines the criterion to select the open objects that would be replicated or not, according to its dimensions. To force any open objects to not be replicated, use the Surfaces to not duplicate option included in Advanced Options. The criterion may be edited:
• Automatic replication Any object with a total area greater than
(1) $a\ge 10\cdot {\left(\frac{lambda}{maximum\left(di{v}_{plane},di{v}_{curve}\right)}\right)}^{2}$
square meters is replicated, where div_plane and div_curve are the number of divisions per wavelength for planar and curved surfaces.. It is the default option.
• Replicate all open objects every open objects are replicated.
• Objects with area greater than To specify manually the threshold of the minimum total area of the open objects to be replicated, in square meters.
• Replication Distance The distance between the original objects and their parallel replicas can also be edited. Two different methods are available:
• Automatically calculate By default, the distance (in meters) is given by the following expression:
(2) $d=0.03\cdot \left(\frac{lambda}{maximum\left(di{v}_{plane},di{v}_{curve}\right)}\right)$
• Specified distance To specify manually the desired distance, in meters.