A source is a separate type of entity which can be used to:

  • Control grid density in connectors (assigned to the Automatic distribution function or a T-Rex boundary condition with Adapt turned On)
  • Control grid density in the isotropic region of unstructured blocks and domains (i.e. it does not affect T-Rex layers or the interior of domains initialized using the Thin Surface Interpolation algorithm)
  • Adapt the interior of structured and voxel blocks
  • Adapt the bounding domains of all block types (i.e. structured, unstructured, and voxel)
  • Align the isotropic cells of unstructured domains in a general direction defined by a source curve
The effect of sources in structured, unstructured, and voxel blocks.
Sources can be used to adapt the interior and the boundaries of all block types (i.e. structured, unstructured, and voxel).

Source entities can be created using the following tools in the Create menu:

Additionally, it is also possible to create point cloud sources using the Create Point Cloud option in the Examine command. These sources may have Constant spacing type (see below), meaning they will apply a constant-value target spacing and decay throughout. Or they may have a General spacing type, where the target spacing can vary per point. The Spacing Type available to apply to a point cloud created within Examine will be dependent on the diagnostic being viewed. Additionally, you can directly import a point cloud source via File, Import, Sources and create a point cloud source via Glyph.

By default, any source located inside a region computed as twice the size of the extent box of a given block or domain will be automatically set to influence the grid entity's size field. This influence is achieved by converting the source into a cloud of points. Furthermore, this point cloud representation will increase in density as spacing values get smaller. This in turn will increase the time necessary for the unstructured solver to initialize the interior of a block. The influence of individual sources can be turned on/off in the Grid, Solve, Size Field command tab.


Tip: It is prudent to initially use conservative values of source spacing in order to decrease the time it takes for a block to be initialized.

When sources are automatically set to influence the size field of a given block or domain, an out-of-sync icon ( In-Sync Sources Icon ) may be displayed in the List panel next to the grid entity's name. This icon indicates that the current distribution of cells in the grid entity and its size field (affected by source entities) are not in-sync. In this case, the grid entity will need to be updated in order to reflect the influence of the sources and the icon will remain displayed until this is done.

The Sources panel (shown below) is primarily used to adjust Spacing and Decay values for your existing, selected sources. Note that at least one source entity must be selected for the Grid, Sources command to be enabled.

Adjust your source Spacing and Decay using the Sources panel.
Adjust your source Spacing and Decay using the Sources panel.

Newly created sources will have default values for Spacing and Decay set automatically from those found in the Defaults panel. These values can be updated here or in the Grid, Solve, Size Field command tab.

Spacing and Decay values are applied at the beginning and end locations of each source. These locations are determined by the order in which the ends of the source were originally created. At the top of the Sources panel, there is a table listing current values of spacing and decay for the selected source. If multiple sources are selected, average values will be displayed.

Below the table, the Beginning/Constant Values frame provides entry fields to input new values of Spacing and Decay for the beginning of the currently selected source(s). The Decay parameter has a default value of 0.5 and it varies from 0.0 to 1.0; a value of 0.0 indicates no influence beyond the boundary of the selected source(s) while a value of 1.0 indicates maximum influence. Note that if the selected source has been set to type Constant (see below), it will only be necessary to input the Spacing and Decay values in the Beginning/Constant Values frame for the entire source.

Likewise, additional fields are available in the Ending Values frame to enter values for the end of the currently selected source(s).

Below the input frames you will find the Reverse and Start Interactive Edit commands. The Reverse command allows you to swap beginning and end Spacing and Decay values for the currently selected source(s). The Start Interactive Edit command puts you into a graphical mode for adjusting spacing values at the beginning and end locations. A relatively sized ring (see image below) can be clicked and dragged in the Display window to adjust the corresponding value. The new spacing is dynamically updated in the table for the selected location. When finished adjusting, click Stop Interactive Edit to end the graphical interaction mode.

Sources Interactive Mode
Start Interactive Mode allows graphical adjustment of the source spacing values.

Finally, at the bottom of the Sources panel you will find the Spacing Type frame, which shows and allows you to select the type of distribution used by the selected source(s).

  • Constant: It changes the source to single valued for spacing and decay throughout the source entity. This will require only a single input for each value, which is the reason the Beginning/Constant Values frame is labeled as such.
  • Parametric (default): Varies the spacing linearly along the source from beginning to end.
  • Axis to Perimeter: Varies the spacing linearly from the axis of the source to its perimeter.
  • Center to Perimeter: Uses a point location and varies the spacing linearly from that point to the entire boundary of the source.
  • Align Only: This option is only available for source curves and it specifies that a given source curve should be used only for domain alignment purposes (i.e. no grid refinement). Refer to the Surface Shape section for more information on domain source alignment.
  • General: Is a special case shown only to indicate what are point cloud sources. Point cloud sources can be created via the Examine command, by direct import from a file using File, Import, Sources, or using Glyph.

The table below shows the different Spacing Type options available for each type of source entity: shape, curve, point, and point cloud.

Source Type Constant Parametric Axis to Perimeter Center to Perimeter Align Only General
Shape (Create, Draw Shapes)
Curve (Create, Draw Curves)
Point (Create, Points)
Point Cloud (Create Point Cloud)


An Introduction to Sources

Creating Sources

Setting Source Attributes

Source Distribution Types