Split (Ctrl+Q)

Description

The Split command splits an entity at user specified XYZ, IJK, X/Y/Z or UV locations. Split is available for all entities except unstructured domains and blocks, with the exception of unstructured T-Rex blocks. The latter can be split to separate the T-Rex region from the remainder of the block volume comprised of isotropic tetrahedra. Note when entities belonging to a group are split, the resulting entities will remain in the original group.

Select Edit, Split. Select a Split Direction which will determine along what parameterized line or computational line/plane the split will occur. Select the split locations by selecting a point in the Display window, specifying an XYZ, UV or IJK point in the Split Location frame, or by using the Slide Point right and/or left arrows. If the last split location chosen is undesirable, it can be deleted by using Delete Last Point. To change a split location not yet applied, place the cursor over the split location, hold the Ctrl key, left-click the point with your mouse, then drag the point while holding the left-click button or enter a new value into a text field. Click OK to split at the selected split locations or Cancel to exit the Split command without saving any changes.

The Split panel that appears depends on the type of entity you select. For connectors or database curves, the Split panel provides options for setting a specific location (XYZ), a percent of the curve’s arc length, a control point location, a grid point location, or a constant X/Y/Z (see figure above). For database surfaces, domains and blocks, the Split panel allows you to choose a split direction and/or a specific location. It also allows you to split a surface along a discontinuity. For shell entities, the Split panel allows a split plane to be defined or selected from the Display window.

Within the Split panel, several frames are provided that control how entities are split. In the Split Location frame:

• XYZ: Sets the XYZ coordinates of the point at which the entity will be split. If the entity is a domain or surface, the XYZ coordinates will represent a point on the computational line along which it will be split. For blocks, the XYZ coordinates will represent a point on a computational plane by which it will be split.

The Advanced frame within the Split Location frame contains other options by which the split location can be specified, such as UV or XYZ Offset. More about these options can be found in the Point Placement section.

• Delete Last Point: Allows the last defined split location to be deleted from memory.
• Slide Point: Allows the last defined or selected split location to be moved in the Split Direction (not available when a connector has been selected).

The Curve Options frame only appears when a connector or database curve has been selected for splitting.

• Percent of Length: Sets the split point to be a percentage of the arc length of the curve.
• Split Anywhere: Allows the split location to occur anywhere on the curve.
• Split Only at Control Points: Allows the split location to be constrained to control points only.
• Split Only At Grid Points: Allows the split location to be constrained to connector grid points only.
• Split Only At Coordinate: Allows the split location to occur at given X, Y, or Z locations.

The Split At Discontinuities frame is available whenever a database surface has been selected. This feature will place points along the curve where discontinuities are found.

The Split Direction frame is available whenever a database surface, domain or block has been selected. The options available within this frame can change depending on whether a database surface or grid entity is selected.

• U: Allows split locations to fall along lines of constant U on a database surface.
• V: Allows split locations to fall along lines of constant V on a database surface.
• I: Allows split locations to fall along a line (or computational plane for blocks) of constant I.
• J: Allows split locations to fall along a line (or computational plane for blocks) of constant J.
• K: Allows split locations to fall along a line (or computational plane for blocks) of constant K.

The Split command for T-Rex blocks provides tools specifically for splitting the T-Rex region away from the isotropic field.

Using the Distance Split Type for a T-Rex block; the table is populated after domain selection.

Within the Split panel for T-Rex blocks, shown above left, you will find specialized tools for defining the split location. A set of choices allow you to select a split location as either a Distance from the selected domains, or as a specific T-Rex Layer. The default choice, and recommended practice, is to use Distance and to set a value slightly outside the T-Rex maximum layer so as not to cut oddly through T-Rex layers and the transitioning cells adjacent to them. Using this approach, you must select the domains which make up the wall BCs which were set in the solver to grow T-Rex layers. Click Begin in the Select Target Domains frame. By default the original wall T-Rex fronts should populate the list that appears. After you End the selection the table at the top of the Split panel is populated with useful statics on the number of number of T-Rex layers and total height, among other things (see image above right). Using the listed total height as a reference enter a slightly larger value into the Distance text field. Once the distance value is entered a preview of the split location, see images below, is rendered in white in the Display. This preview can be turned off by unchecking Show Preview. Click OK to split. Two blocks will remain, one primarily the T-Rex layers, the other the remaining isotropic field volume.

Wing-pylon-store T-Rex topology prior to splitting.

Split command with preview shown of split location just outside the T-Rex layers.

When using the Split command for T-Rex blocks via the T-Rex Layer selection for Split Type, the panel, shown below, changes slightly. Now the fronts in for the original T-Rex walls must be selected rather than domains. The Distance field is replaced with a T-Rex Layer Number field, and that field is automatically populated with the total layer count for the selected fronts. So basically the split location defaults to the uppermost T-Rex layer. Again, as with using the Distance option, the split location is previewed in the Display window by default as shown in the images above.

Within the Split Shell panel, several options are provided that define the plane for splitting a selected shell. Please refer to the Planes section for the discussion on the modes: Point and Normal, Three Points, Constant X, Y, or Z, and Coefficients. The Select A Plane mode allows a plane selection in the Display window or the List panel.