Morphing a mesh

Mesh morphing is a process for updating an existing mesh to conform to geometry modifications without regenerating the entire mesh. When you morph a mesh, the software tries to keep the overall mesh topology constant. The software computes new locations for the nodes in the existing mesh to conform to the changed geometry and expands or shrinks the mesh to fit the modified geometry.

Morphing provides an alternative to the mesh update that occurs within the Model Update solution process. With a mesh update, the software deletes and recreates meshes that are affected by change to the underlying geometry.

You may want to morph, rather than update, a mesh when:

• It is important that you preserve your current node and element labels.

• You want to retain the shape and size of the existing elements in a mesh in areas that are unaffected by the modifications to the CAD geometry.

For example, it is a standard design procedure to reuse legacy finite element models that have very minor modifications to the underlying geometry. These modifications generally involve the repositioning of or re-sizing of existing features. The modified surface is topologically identical to the original surface though its geometry is different. Rather than regenerate the entire mesh on the modified geometry, you can use the mesh morphing commands to update the appropriate node and element locations to reflect the geometric change.

In some cases, for example, you may want to preserve your existing mesh and expand or shrink the existing elements to fit the new geometry. In the example, (1) shows an existing mesh inside the outline of new geometry, and (2) shows how the existing mesh can be morphed to fill the new geometry.

Automatically morphing a mesh

Use the Automatic Morph command to have the software try to automatically morph a mesh to conform to modified CAD geometry. During this process, the software tries to associate the existing nodes to the new geometry.

The Automatic Morph command is intended for cases in which the CAD geometry is modified but does not have any topological changes; that is there are no additions or deletions of vertices, edges, or faces. Ideally, you should use the Automatic Morph command immediately after the CAD geometry is modified.

For more information, see Automatically morphing a mesh.

Manually morphing a mesh

Use the Manual Morph command to manually morph existing nodes and elements to conform to modified CAD geometry. You must manually define the associations between the existing nodes and the updated CAD geometry.

Use the Manual Morph command when:

• You want to morph a mesh to conform to updated CAD geometry that has topology modifications.

• The Automatic Morph command is not able to automatically associate the existing nodes to the new geometry.

• Only selected elements need to be morphed to achieve a localized change.

• You want to update a specific region of an orphan mesh, which is a mesh with no existing geometry association.

For more information, see Manually morphing a mesh.

Saving full morphing data

When you create a FEM file, you can use the Save Full Morphing Data option in the New FEM dialog box to control whether the software stores comprehensive data about modifications to the underlying CAD geometry. If you plan to use morphing, rather than the FEM Update command, to update the meshes in your model in subsequent sessions, you should select this option. When you select the Save Full Morphing Data option, the software stores additional data about changes to the CAD geometry. If you use the morphing commands in a subsequent session, this additional data allows the software to produce higher quality morphing results.

Note:

The Save Full Morphing Data option does not have any impact on the quality of morphing results when you modify the CAE geometry and morph an associated mesh in the same session.

Manually associating and disassociating nodes from geometry

• Use the Node Association command to associate the orphan nodes in a mesh to nearby geometry within a specified tolerance. This command controls only the geometry association between a node and geometry. It does not change the location of a node. The software tries to associate any elements connected to the nodes to the appropriate geometry, if possible.

• Use the Node Dissociation command to remove the association between a node and the geometry. This command is useful for cases in which the association between a node and the geometry is incorrect, such as when a node is associated to the wrong edge in a part. The Node Dissociation command also disassociates any elements that are connected to the dissociated nodes from the geometry.

• Use the Check Association command to check the association between nodes and geometry.

For more information, see Node and element association during morphing.

Morphing a mesh disables the FEM Update command

The morphing commands follow a different process for updating a mesh than the FEM Update command. As a result, the software disables the FEM Update command after you modify a mesh with any of the morphing commands.

To re-enable the FEM Update command, right-click the FEM and select Enable FEM Update. If you choose to re-enable the FEM Update command, the software disassociates all nodes in the morphed meshes from their geometry.

Where do I find it?

Application	Pre/Post
Prerequisite	A FEM file as the work part and displayed part
Command Finder	Automatic Morph , Manual Morph , Node Association , Node Dissociation , Check Node Association

Quick links

Command reference

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Morphing a mesh, Simcenter 3D 2021.1 Series

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