Infinite Box: Complete the Infinite Box

Infinite box : reminder

The main domain of finite element computation is, in many cases, surrounded by a special region called Infinite Box (IB).

This technique permits the user to limit the size of the finite element computation domainand takes into account the infinite.

Construction of the IB

The Infinite Box is created as follows:

Stage Description

Creation of points and lines in the Infinite Box :

Command: Create Infinite Box


Creation of closing lines if necessary :

Command: Create Line


Construction of faces :

Command: Construct face


Construction of volumes in 3D :

Command: Construct volume

Completing IB

To facilitate the user's work, stages 2, 3 and 4 can be carried out at one time by the command: Complete Infinite Box .

Remark: in case of imported mesh (see HyperMesh (and OptiStruct) and SimLab mesh import), a specific building option allows creating lines, faces, volumes and mesh for the non-meshed parts. This option is called “add geometry and mesh after mesh import”.


The use of the command Complete Infinite Box, in the case of a 3D device with 3 plans of symmetry, is presented in the figures below.

Effect of the command "Create IB"

Effect of the command "Complete IB"

In the presence of periodicity

In case of devices with repetitive geometry the computation domain represents a reduced portion of the device (the basic geometry). It is possible to set the appropriate boundary conditions of periodicities to the periodicity plans.

Like the command Propagate face , the command Complete IB offers the user an option to create a linked mesh generator that is associated to the repetitive faces.