What Are Regions?

Regions are volume domains (or areas in a two-dimensional case) in space that are completely surrounded by boundaries.

Regions are not necessarily contiguous, and, apart from particle regions, are discretized by a conformal mesh consisting of connected faces, cells and vertices. Particle regions are formed by a discretized surface mesh only—they do not contain any volume mesh.

One region is joined to another using an interface, so that information can be passed between them. Boundaries are not shared between regions.

There may be multiple regions in a simulation, each with a unique name and properties, as well as a pop-up menu. Region nodes are created when you:

Import a mesh -- from native CAD, neutral format, surface mesh (without using geometry parts), or volume mesh formats
Split a non-contiguous region
Assign parts to regions, see Regions Layout Workflow

Each region node is given a unique name during the import process, but it can be renamed.

The node icon is based on the region type. You can also work with region nodes using drag-and-drop actions.

Using Drag-and-Drop with a Region Node

Dragging a region node onto another region node will copy all the properties of the source region to the destination region, including region condition methods, but excluding the region name.
Dragging a region onto the Parts node of a scene displayer will add all the boundaries to the scene.
Dropping a continuum onto a region will associate the region with that continuum (the same as setting the Continuum property).

Region Properties


Index	Index reference for region (read only).
Physics Continuum	Defines the physics continuum associated with this region. Select from a drop down list of all the available continua in the simulation.
Parts	Specifies the parts included in the region, using the parts selection dialog.
Type	Defines the type of the region depending on the material model selected. This is primarily used to define porosity in a region associated with a gas or liquid physics continuum. A region associated with a solid continuum only allows one option. This property will be changed if the material model of the associated continuum is changed from gas or liquid to solid (and vice versa).
	Fluid Region	The region is associated with a gas or liquid continuum. No porous modeling is applied.
	Solid Region	The region is associated with a solid continuum.
	Porous Region	The region is associated with a gas or liquid continuum, and porous media modeling assumptions apply.
	Particle Region	The region is associated with a meshfree volume, and only particles can occupy it.
Topology (read-only)	Volume	The volume region topology indicates that the region is represented with a volume mesh.
Topology (read-only)	Surface	The surface region topology indicates that a surface mesh represents the region. This option applies specifically to Smoothed-Particle Hydrodynamics (SPH) multiphase simulations.
Allow Per-Part Values	When activated, creates the Parts Groupings node under the region node. All parts in a given group under this node have the same profile assigned to them. See Usage Details.
	Activated	Creates the Parts Groupings node.
	Deactivated	No Parts Groupings node is created. This is the default.

Region Pop-Up Menu


Highlight	Highlights a region in a scene. This option is only available if the scene is open.
Edit...	Opens the table editor, which combines the functionality of the simulation tree and Properties window. It displays the selected region, all of its child nodes, and their properties in a single dialog.
Combine	Executes the combine regions action to combine the selected regions (two or more) into one region.
Boolean	Applies Boolean operations in the submenu to the selected regions.
	Unite Regions	Performs a Boolean unite operation.
	Intersect Regions	Performs a Boolean intersect operation.
	Subtract...	Performs a Boolean subtract operation.
Split by Surface Topology	Executes the split by surface topology action to split closed, semi-manifold surface meshes that belong to a single region into their constituent regions.
Split Non-Contiguous	Executes the split non-contiguous region action to split the selected regions into multiple contiguous regions if possible. If more than one region is selected, the action will operate on each region in sequence.
Split by Function...	Executes the split by function action to split a region according to the rounded integer value of a selected field function.
Remove Invalid Cells...	Executes the remove invalid cells action to move cells below a user defined threshold quality into another region so that they are not included as part of the analysis. Not available for finite element physics models.
Transform	Scales, translates or rotates the selected regions and all associated boundaries. These actions operate on one or multiple regions, and if more than one region is selected, the transform action will be applied to each region in sequence.
	Scale...	Executes the scale region action.
	Translate...	Executes the translate regions action.
	Rotate...	Executes the rotate region action.
	Reflect...	Executes the reflect region action.
Reorder Mesh	Reorders the internal references to cells in the volume mesh region in order to optimize the solver performance in terms of memory usage.
Replace Mesh...	Executes the replace mesh action to replace the mesh of the selected region with that of another.
Solution	Applies operations in the submenu to the individual region.
	Clear	Executes the clear region solution action. Unavailable for Finite Element physics models.
Create Interface	Creates a heat exchanger interface between selected regions.