Mesh Column Operations

Column operations allow users direct control over the mesh connectivity while maintaining full-geometric associativity.  Often, hex meshing schemes such as sweeping and mapping result in mesh topology forced into unnatural shapes, such as a square shaped source surface mesh getting swept into a circular target surface.  Often forcing meshes into shapes like this results in poor element quality because of non-optimal element angles.  The Column commands allow users to directly modify mesh topology to make minor tweaks to a mesh improving element quality.  Column operations are almost always followed by smoothing to enable element quality improvement.
 
Cubit provides tools to perform insertion, deletion, swapping, grouping, and drawing of hex columns.

Column Insertion

A single column can be inserted into the mesh by using the following command:

column open node <center node id> <orientation node ids>

For example, given the following meshed brick:


we issue the command, column open node 89 88 90 , to get this result:

 

Column Deletion

Columns can be removed with neighboring columns being joined together using collapse commands. Collapse commands are of two types: interior and boundary.

For interior node collapse, the two nodes which are opposite on a face are combined together. The column associated with the face is removed. Use the following command:

column collapse node <opposite node ids>

For example, given the following meshed brick:


we issue the command, column collapse node 51 59, to get this result:

The column collapse command can be used with boundary nodes. For example, we issue the command, column collapse boundary node 13 2 11, to get this result:

Column Swapping

Faces between two hex columns can be swapped using the following command:

column swap node <old edge node ids> <new edge node ids>

For example, given the following meshed brick:


we issue the command, column swap node 103 94 102 18, to get this result:

Column Groups

A group consisting of hexes that comprise a column can be created using the following command:

column { face <id> | edge <id1> <id2> | hex <id1> <id2> } group

Drawing Columns

Columns can be drawn using the following command:

draw column { face <id> | edge <id1> <id2> | hex <id1> <id2>}