Understanding the mesh update process

A mesh may require an update when:

• The mesh is modified. For example, you may modify a mesh by changing the element size or by changing some of the mesh options.

• The geometry that underlies the mesh is modified.

• Adjacent meshes or the underlying geometry of adjacent meshes is modified.

When you use the Model Update commands, the software follows a multi-step process to systematically update the meshes in your FEM file. The software updates:

• Any meshes marked in the Simulation Navigator as update pending.

• Any meshes that are adjacent to or related to those update pending meshes.

When you use the Model Update commands to update the meshes in your FEM file, the software generates a Mesh Update Log file that provides detailed information about the mesh update process for your particular model. The log file lists, for example:

• The meshes that were updated.

• The order in which the meshes were updated.

• Any errors that occurred during the mesh update process.

• Any manual meshes in which the updates resulted in elements being deleted.

You can use the information in the log file to better track the changes that occur to your meshes when the FEM file updates.

Mesh Update Logging customer default

You can use the Mesh Update Logging customer default to control the display of the mesh update log file. You can choose to:

• Always display the mesh update log.

• Never display the mesh update log.

• Ask you whether you want to display the mesh update log only when errors or warnings are encountered during the update process.

Propagation of changes to 2D mapped meshes

The software begins the update process by looking for meshes created with the 2D Mapped Mesh command that have a status of update pending in the Simulation Navigator. The software:

• Examines the geometry associated with any 2D mapped meshes that are marked as update pending to identify any adjacent mapped meshes that might be affected by the update.

• If any of the adjacent mapped meshes were created at a later time than the current update pending mapped mesh, the software marks these meshes as update pending as well.

Note:

The process of identifying adjacent meshes that are affected by an update is referred to as propagation.

In addition, the software identifies any of the following types of meshes that would be affected by updating the 2D mapped meshes:

• Any meshes created with the Surface Contact Mesh command.

• Any 3D meshes that are constrained by an update pending 2D mapped mesh.

• Any 1D meshes that are associated with an update pending 2D mapped mesh.

Propagation of changes to 3D swept meshes

The software next examines all meshes created with the 3D Swept Mesh command that have a status of update pending in the Simulation Navigator. If any of the adjacent 3D meshes were created at a later time than the current update pending 3D Swept Mesh, the software marks those meshes as update pending as well.

Abstraction of geometry related to the updated meshes

The software then makes updates to any of the polygon geometry that is associated with the updated meshes. For example, if you had used the Stitch Edge command to automatically stitch an edge or faces associated with an update pending mesh, the software uses the Stitch Edge recipe to try to recreate the stitching operations as it updates the polygon geometry.

Update of weld meshes

During this stage, the software updates weld meshes that have a status of update pending as follows:

• The software first updates all meshes created with the Spot Weld command.

• The software then updates all meshes created with the Weld Mesh command. The software marks any 2D or 3D meshes that are dependent on the updated weld mesh as update pending.

• The software then updates all edge contact meshes created with the Contact Mesh command. The software marks any 1D meshes that are dependent on the updated contact mesh as update pending.

Initial update of pre-NX 6 Edge-Face Connection meshes

The Edge-Face Connection command existed in NX 5 and previous releases. It was replaced in NX 6 by the 1D Connection command. If a model contains any legacy Edge-Face Connection meshes that were created with the Match Meshes option turned on, the software makes a preliminary update of those meshes at this point.

Update of 2D meshes

Next, the software updates all 2D meshes created with the 2D Mesh, 2D Mapped Mesh, and 2D Dependent Mesh commands that have been marked as update pending.

Update of 3D meshes

The software then updates any 3D meshes. First, it updates meshes created with the 3D Swept Mesh command. Then, it updates meshes created with the 3D Tetrahedral Mesh command. Then, the software updates any 2D surface coat meshes (created with the Surface Coat command) associated with the updated 3D meshes.

Update of 1D Meshes

The software then updates any meshes created with the 1D Mesh command that have been marked as update pending.

Update of Edge-Face Connection meshes

With the 2D, 3D, and 1D meshes in the model updated, the software then performs a second and final update of any legacy Edge-Face Connection meshes that were created with the Match Meshes option turned on.

Update of 2D Surface Contact Meshes

The software then updates any dependent meshes created with the Surface Contact Mesh command. This command is only available in the Simcenter Nastran and MSC Nastran solver environments.

Update of 0D Meshes

The software then updates any meshes created with the 0D Mesh command that have been marked as update pending.

Update of 1D Connection Meshes

The software then updates any dependent meshes created with the 1D Connection command that have been marked as update pending.

Update of Surface Coat Meshes

Finally, the software updates any dependent meshes created with the Surface Coat command that have been marked as update pending.

Reporting of deleted elements from manual meshes

In some cases, the software may need to delete elements from meshes that were created with one of the commands on the Element Operations toolbar, such as 3D Sweep Between. If that occurs, the software lists how many elements were deleted and the meshes from which they were deleted in the Mesh Update Log.

Learn more

Setting element size

Element size for acoustic analysis

Understanding the Automatic Element Size calculation

Understanding curvature-based size variation

Understanding the Snap Tolerance value

Show Tiny Edges

Multi-block decomposition in meshing

Controlling the proximity of nodes to the CAD Geometry

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Understanding the mesh update process, Simcenter 3D 2021.1 Series

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