Creo Simulate > Modeling Structure and Thermal Problems > Meshes > FEM Meshes > Assembly Meshing > Hierarchical Meshing > Hierarchical Meshing
Hierarchical Meshing
For hierarchical meshing, Creo Simulate assumes your design goal is a mesh model that contains both the top-level assembly mesh and pre-existing component meshes for one or more individual components. For convenience, this discussion refers to components with pre-existing meshes as pre-meshed components. A pre-meshed component can be an individual part or a subassembly.
Development of a hierarchical mesh may involve gathering meshes from multiple designers, deciding which meshes to use or omit, and so forth. To ensure that you complete all the required modeling phases, you may want to use a specific workflow when developing a hierarchical mesh.
Because you can only use hierarchical meshing if you configure your session to use retained meshes, be sure to set the fem_hierarchical_mesh configuration option before starting Creo Simulate. With this option set, Creo Simulate checks the current directory when you open your model in FEM mode. If it finds any existing component meshes, it brings those meshes into the session. Thus, as your model opens, you see meshes on pre-meshed components. Components that have no pre-existing meshes display geometry only.
As with flat meshing, you should add connections to ensure that loads transmit between unmeshed components that have no mated surfaces or overlapping edges. You must also explicitly connect any pre-meshed component to the rest of the assembly. As a prerequisite for this, the component must have hard points where you want the connections before you generate the component-level mesh. If you do not use hard points, Creo Simulate disregards the connection when you create the top-level assembly mesh.
The way the mesh generator combines individual meshes to form a hierarchical mesh can be complex. To learn how Creo Simulate builds hierarchical meshes and handles pre-meshed components, see Understanding Hierarchical Meshes.
After you create a hierarchical mesh, you can run your model online or output your model for analysis with your solver. If you choose the latter method, the output is such that it will allow the solver to handle the assembly mesh hierarchically. However, the exact arrangement of the output file is slightly different for NASTRAN than it is for the other solvers. After your run is complete, you can view the results of your analysis within Creo Simulate.