The Boundary Conditions panel provides tools for creating, assigning, and deleting boundary condition filters to control how boundaries are used by T-Rex for growing layers of anisotropic cells to form the boundary layer.
The first five rows of the Boundary Conditions table show the default boundary condition filters to which domains are automatically assigned by Automatic Volume Mesh: Isotropic, Boundary Layer, Match, Symmetry, and Periodic. These filters cannot be deleted or renamed nor can their Type be edited. Default filters are automatically placed at a lower priority than user-defined filters. See the Default Boundary Condition Filter section below for more information on which domains are automatically assigned to each default filter.
The buttons (New, Delete, Add to Selection, , , , and ) and first 4 columns in the table (priority, Set, #, and Name) all function the same as other filters in the Flashpoint toolset. Please refer to the Flashpoint Filters section for more information.
The Type and Δ columns are specific to boundary layer growth and are disabled if the Boundary Layer parameter on the Global tab is set to Off. Otherwise, use the dropdown in the Type column to choose from the boundary condition types described below. For more information about T-Rex and its boundary condition types, please refer to the T-Rex BC section of this User Manual.
Caution: Even though the Angle, Aspect Ratio, and Max. Aspect Ratio boundary condition types appear in the list, these types are specific to surface meshing and should not be used for volume meshing. For more information on how to use these boundary conditions in your surface meshing, please review the Automatic Surface Mesh and 2D T-Rex sections of this User Manual.
Tip: The Match boundary condition type is best suited for domains that are adjacent to domains set to a Wall or Adjacent Grid boundary condition since it will automatically update the domain's interior cell distribution to match the growth profile of the anisotropic layers being grown.
Note: The Adjacent Grid boundary condition should only be used for domains that interface with another block and both sides of the interface need to be used for growing the boundary layer. In that case, you can set the interface in one of the blocks to an Adjacent Grid boundary condition to use the same initial spacing in both blocks.
The Adapt column allows you to specify whether or not the domains assigned to that boundary condition should be adapted to sources and other size field influencers. Use the dropdown to toggle between On and Off. By default, Adapt is set to Off for newly created boundary condition filters.
The first five rows of the Boundary Conditions table display the default boundary condition filters to which Automatic Volume Mesh automatically assigns all of the bounding domains:
Note: Domains that belong to a periodic pair always have their periodicity maintained (i.e. they remain identical) regardless of boundary condition Type or Adapt status. If you wish to change the Type simply assign both domains to a user-defined boundary condition with the desired type. If you wish to enable adaption for the periodic pair, it is recommended to assign one domain to a boundary condition with Adapt turned On and assign the other to a boundary condition with Adapt turned Off. This will still update both domains, but is more robust since the size field may produce slightly different results for each domain.
Boundary condition filters are defined by prescribing one or more filter patterns. These are displayed in the table in the filter's frame. This filter pattern table functions similarly to other filter pattern tables within the Flashpoint toolset. Please refer to the Filter Pattern Tables and Wildcard Pattern Matching sections on the Flashpoint Filters page for more information on defining filter patterns.
Tip: Domains created by Automatic Surface Mesh are automatically named according to the name of their underlying quilts. This means that you can use similar name patterns to automatically assign domains to boundary condition filters in Automatic Volume Mesh as you used to assign entities to resolution, mapping, and stretching filters in Automatic Surface Mesh.