Creo Simulate > Modeling Structure and Thermal Problems > Meshes > FEM Meshes > Transient and Retained FEM Meshes > Meshing Guidelines > Invalidating a Mesh
Invalidating a Mesh
If you set your session to use retained meshes, Creo Simulate attempts to preserve the model mesh throughout the session, enabling you to define modeling entities and analyses without perturbing the mesh. However, adding or modifying certain types of modeling entities can invalidate the mesh.
For example, Creo Simulate treats any point that has an applied load or boundary condition as a mesh node. Therefore, if you add a point load to a datum point in your model, the original mesh is no longer valid because it does not account for the newly added node.
While a variety of actions can invalidate a mesh, here is a list of the main causes of mesh invalidation:
In Creo Parametric:
changing model geometry
changing the way assembly components connect
removing assembly components
Modifying or deleting datum features
Creating, modifying, or deleting surface regions or volume regions
Creating or modifying a load, boundary condition, beam, spring, contact, mass, rigid link, or weighted link such that it references a datum point or vertex that you have not already declared as a hard point mesh control. You can, however, change characteristics such as the value of a load, degrees of freedom for a constraint, and so forth without invalidating the mesh.
Creating, modifying, or deleting connections—for example, end welds, perimeter welds, interfaces, and so forth
Creating or deleting idealizations that affect the way the mesh generator meshes the part or assembly. You encounter cases such as this when:
creating a beam idealization on a curve or deleting one from a curve
creating or deleting a shell idealization on a quilt or surface
Creo Simulate only includes bars and quilts in the mesh if you define them as idealizations. Therefore, adding or deleting these idealizations changes the way the mesh generator would treat the part or assembly, thus invalidating the mesh.
Adding, modifying, or deleting a mesh control other than Mesh ID Offset
If you invalidate a mesh, Creo Simulate informs you of the problem during modeling or meshing. If you introduce the invalidating factor at modeling time, Creo Simulate takes one of two actions, depending on whether the factor affects the top-level mesh or a lower-level component mesh:
Top-level Mesh — Creo Simulate warns you of the problem and gives you the option of correcting the invalidating factor. If you do not correct the factor, the software immediately removes the mesh.
Lower-level Component Mesh — Creo Simulate warns you of the problem, but leaves the mesh intact until you next mesh the component. At that time, Creo Simulate respects the mesh, but silently ignores the invalidating factor.