# HM-3220: Create a Hexahedral Mesh

Solids are geometric entities that define a three-dimensional volume. The use of solid geometry is helpful when dividing a part into multiple volumes. For example, divide a part into simple, mappable regions to hex mesh the part. Use the Solid Map panel to create a mesh of solid elements in a solid geometric volume.

In this tutorial, you will learn how to create a hexahedral mesh using the Solid map function by one volume and multisolid method.

This exercise uses the solid_map.hm file, which can be found in the hm.zip file. Copy the file from this directory to your working directory.

## Open the Model File

In this step you will open the model file, solid_map.hm.

1. Start HyperMesh Desktop.
2. From the menu bar, click File > Open > Model.
3. In the Open Model dialog, open the solid_map.hm model file.

## Mesh the Sphere Region

In this step you will mesh the 1/8th sphere-shaped region.

1. Shade the model's geometry and surface edges by clicking on the Visualization toolbar.
2. Open the Solid Map Mesh panel by clicking Mesh > Create > Solid Map Mesh from the menu bar.
3. Go to the one volume subpanel.
4. Under along parameters, type 1 in the elem size= field.
5. Activate the volume to mesh: solid entity selector.
6. Select the small cube-shaped solid as indicated in the following image.
7. Click mesh.
8. Shade the model's elements and mesh lines by clicking on the Visualization toolbar.
9. Select the solid as indicated in the following image.
10. Click mesh.

## Create a Shell Mesh Using Automesh

In this step you will create a shell mesh with the Automesh panel to control a mesh pattern.

1. Open the Automesh panel by clicking Mesh > Create > 2D AutoMesh from the menu bar.
2. Go to the size and bias subpanel.
3. Select the surface as indicated in the following image.
4. Set the meshing mode to interactive.
5. In the element size= field, type 1.000.
6. Set the mesh type to mixed.
7. Click mesh.
The meshing module opens.
8. Verify that you are in the density subpanel.
9. In the elem density= field, type 4.
10. Click set all to.
All edge densities are set to 4.
11. Click mesh.

## Mesh the Solid Volume

In this step you will mesh the solid volume on which the surface mesh was created in Step 3.

1. Open the Solid Map Mesh panel.
2. Go to the one volume subpanel.
3. Select the volume shown in the following image.
4. Under along parameters, toggle elem size= to density=.
5. In the density= field, type 10.
6. Click mesh.
7. Rotate the part and note how the mesh pattern created with the Automesh panel has been used for the solid elements.

## Mesh Solid Volumes That Remain

In this step you will mesh the remaining solid volumes.

1. Select one of the remaining unmeshed solid volumes.
Note: Make sure to select a solid adjacent to one that has already been meshed so that connectivity is maintained.
2. Set the source shells to mixed.
3. Under along parameters, toggle density= to elem size=.
4. In the elem size= field, type 1.5.
5. Click mesh.
6. Repeat until all solid volumes are meshed.

In this optional step you will save your work.

From the menu bar, click File > Save > Model.

## Automated Solid Map Meshing

The capability to automate the solid map meshing process is now available.

Using the “Mappable” visualization mode in conjunction with the multi-solids feature will inform you that the solid(s) are ready for solid meshing. Using the multi-solids feature will allow for all solids within the model to be meshed in one step, provided that they are mappable.

In this section of the tutorial, you will delete all of the elements from the previous section. You will then use the Mappable visualization mode with multi-solids to solid mesh the part.

## Delete Elements

In this step you will delete the elements within the model.

1. Open the Delete panel by pressing F2.
2. Click elems >> all.
3. Click delete entity.

## Use the Mappable Visualization Mode

In this step you will use the mappable visualization mode.

1. Shade the model's geometry and surface edges by clicking on the Visualization toolbar.
2. From the Geometry Visualization list, select .
HyperMesh color codes each solid to represent its mappable state.
Note: The goal is to ensure that each solid is either 1-directional or 3-directional mappable.
3. From the menu bar, click Preferences > Colors.
4. In the Color dialog, click the Geometry tab.
5. Optional: Under By mappable display mode (solids), click the color swatches to adjust the display color of the following:
• 1dir.map: Visualization for solids that can be mapped for 3D meshing in one direction.
• 3dir.map: Visualization for solids that can be mapped for 3D meshing in three directions.
• Ignored map: Default visualization for solids that require partitioning to become mappable.
• Not mappable: Visualization for solids that have been edited but still require further partitioning to create mappable solids.
Note: Once in the mappable visualization mode, it is clear that there is one 3-directional mappable solid and the rest are 1-directional mappable.

## Use Multi-Solid to Mesh Part

In this step you will use the multi-solid feature to mesh the part.

1. Open the Solid Map Mesh panel.
2. Go to the multi solids subpanel.
3. Click solids >> all.
All solids are selected.
4. Set the source shells to mixed.
5. In the elem size field, type 1.
6. Click mesh.
Interactive mesh mode opens.
7. Accept the shell elements and create solid elements by clicking mesh.
Note: The solids will be sequentially solid meshed.
8. Inspect the model and note that the mesh within the solids is correctly equivalenced.
9. Accept the solid element mesh and return to the Solid Map Mesh panel by clicking return.