Assigning Mesh Regions

In Icepak, a mesh region can be defined around particular geometry by selecting the geometry in the history tree or 3D Modeler window, right-clicking, and selecting Assign Mesh Region. Prior to defining mesh settings, you must first define the padding settings. Padding allows you to expand or shrink a mesh region in each coordinate direction. Each mesh region face can be adjusted outwardly or inwardly. Specify a positive value to expand the mesh region or a negative value to shrink it.

Note: A mesh region cannot be shrunk to a volume of zero or expanded outside the outer Region (computational domain).

A non-model sub-region is created using the current coordinate system. This region can be meshed independently of the global mesh outside it. At the interface with the global mesh region, there is a many-to-one transition between the mesh cells inside the mesh region and those outside it in the global mesh region, and a non-conformal interface is created at the boundary between the meshes. This allows for the embedding of a fine mesh within the mesh region around geometry where it is needed and for a coarse mesh in the rest of the model.

Padding Data
Pad all directions similarly	Select Pad all directions similarly to specify padding as a single value that affects all directions. In this case, you can specify the Padding type by selecting Percentage Offset or Absolute Offset from the drop-down menu. If you select Absolute Offset, also specify the Units.
Pad individual directions	Select Pad individual directions to specify padding for each coordinate direction individually. In this case, you can specify the Padding type by selecting Percentage Offset or Absolute Offset or Absolute Position from the drop-down menu.
Transverse padding	Select Transverse padding to specify padding for each coordinate direction by a percentage of the other two coordinate direction's diagonal length. For example, the X direction is padded using the specified percentage of the diagonal length of the other two directions (Y and Z).

List of Selected Parts	List of Selected Parts displays all pieces of geometry that will be enclosed within the mesh region.

Auto Mesh Setting
Name	The Name of the mesh region appears in the Project Manager window and 3D Modeler window.
Resolution/Mesh Size	The Auto Mesh Setting slider includes a visual representation of the resolution you choose as ranging from coarse resolution with a small mesh size through a five-position scale to a fine resolution with a large mesh size. Each slider position automatically sets unique values for the following settings found on the Advanced tab: Maximum Element Size, Min. elements in gap, Min. elements on edge, Max size ratio, Multi level meshing Max. Levels, and 3D Multi level mesh. Slider settings 3, 4, and 5 also enable per-object mesh levels.
Enable Mesh Fusion	Enable Mesh Fusion is used to automatically group and mesh geometries in a mesh region that uses the mesh slider bar. When enabled, it divides the geometries into sub-domains, which are then meshed separately using automatically selected meshing methods to yield high quality meshes.
Note: Mesh fusion can be enabled or disabled on a design level in the Global Mesh Region dialog box. It can be enabled or disabled for individual mesh regions on the General tab of the Mesh Region dialog box. See Mesh Fusion for more information.

Maximum Element Size
X, Y, Z	Maximum Element Size specifies the desired maximum element length in each coordinate direction. Typical values are about 1/20 of the region dimensions in the corresponding directions.
Minimum Gap
X, Y, Z	Minimum Gap specifies the minimum distances separating objects in your model in the X, Y, and Z coordinate directions. Minimum gap influences geometry and meshing. Geometry: If the gap between geometries is smaller than 10% of the minimum gap setting, the gap is closed (that is, one geometry is snapped to the match the adjacent geometry). Meshing: Icepak HD Mesher calculates a meshing tolerance based on the minimum gap, domain dimensions, the smallest geometric feature, and other factors. If the tolerance is calculated such that it is smaller than the geometric gap, the gap is meshed.
Mesh Parameters
Min. elements in gap	Min. elements in gap specifies the minimum number of elements between adjacent objects.
Min. elements on edge	Min. elements on edge specifies the minimum number of elements on each edge of each object.
Max size ratio	Max size ratio specifies the maximum ratio of the sizes of adjacent elements (for the whole model).
No O-Grids	No O-Grids (Mesher-HD and Hexa Unstructured only) specifies whether or not objects will have O-grids around them. This option is disabled by default, indicating that Icepak will generate O-grids around all objects, including those that contain other objects.
Allow stair-stepped meshing	Allow stair-stepped meshing disables projection and decomposition during 3D cut cell meshing. The boundary mesh will not be conformal, and the resulting mesh will only approximate the shapes of your geometries. Stair-stepped meshing should only be used if resolving the shape of the geometry is not important.
Multi level Meshing (MLM)
Max. Levels	Max levels specifies the maximum number of levels that may be required to achieve the desired mesh refinement based upon curvature/proximity. For a given coarse mesh, the desired proximity/curvature based refinement may be achieved even before reaching the max levels.
Buffer Layers	Buffer Layers is used in conjunction with multi-level meshing. The default value is zero, which means refinement is not propagated to adjacent layers. When you set this value to a number greater than zero, such as 1 or 2, refinement is propagated to additional mesh layers, which helps in generating better meshes in the region of under-resolved geometry.
Enforce MLM in all objects	Enforce MLM in all objects starts with a coarse background mesh and then refines the mesh in the planar directions to resolve fine-level features. You can select to enforce multi-level meshing in 3D or 2D objects. When 2D is enabled, if necessary, select a coordinate direction to enforce the multi-level meshing in the specified direction. Multi-level mesh refinement is then constrained to the 2D plane.
Uniform mesh parameters	Uniform mesh parameters has two options: Average and XYZ Max. Sizes. Average creates a uniform mesh with the same mesh size in all coordinate directions. The mesh size is computed by averaging the specified max element sizes.XYZ Max. Sizes creates a uniform mesh in each coordinate direction using the corresponding max element size. The resulting mesh has constant spacing in each coordinate direction but the spacing can be different if the max element sizes are different. Using uniform mesh parameters results in lower mesh count and improved quality. It is recommended to use uniform meshing parameters when multi-level meshing is used. If this option is enabled, 3D cut cells and stair-step meshing ignores the object-based parameters to keep the mesh uniform and generates better quality meshes.

You can manually adjust the region size by selecting the mesh region in the history tree and editing the Position, XSize, YSize, and ZSize values. in the Properties window.

To assign a mesh region:

Note: To assign a mesh region to an inclined non-model box, you must first create a relative coordinate system. Then create the non-model box on the relative coordinate system, and assign a mesh region to it.

Select an object in the history tree or 3D Modeler window.
Right-click in the 3D Modeler window and select Assign Mesh Region.
In the SubRegion dialog box, select a Padding Data option and define the following padding settings:

Padding type
Value
Units

In the Mesh dialog box on the General tab, use the Auto Mesh Setting slider to select a mesh resolution between Coarse and Fine.
If needed, select Enable Mesh Fusion.
From the Coordinate System drop-down list, select the coordinate system on which to create the mesh region.
On the Advanced tab, if needed, select the User specified check box to enable and define the following settings:

Maximum Element Size
Minimum Gap
Mesh Parameters
- Min. elements in gap
- Min. elements on edge
- Max Size Ratio
- No O-Grids

If needed, select Enable under Multi level meshing and define the following settings:

Max levels
Buffer Layers
Enforce MLM in all objects
Uniform mesh parameters

If needed, select the mesh region in the history tree and edit the padding values in the Properties window.
Click OK.