Quality Index Cleanup Tools Secondary Panel

In the Quality Index Cleanup Tools secondary panel you can access numerous tools that assist you in manually relocating nodes and optimizing element topology.

Panel Layout

The Quality Index Cleanup Tools secondary panel's layout changes dynamically depending on the cleanup tool you select. The list of cleanup tools is always displayed along the left-hand side of the panel. The criteria for the currently active cleanup tool displays in the second column, and the current composite Quality Index, patch checker, and action buttons display in the third column.

qi_cleanup_secondary_panel

Subpanels and Inputs

There are no subpanels on the Quality Index Cleanup Tools secondary panel. However, the following cleanup tools each use their own set of entry fields:

Panel Inputs

Input	Action
along surface / normal to surface	Use this toggle to determine which direction the node will move. To move the node along the plane or curvature of the surface, select along surface. To move the node directly away from the surface in a normal direction, select normal to surface. Movement along surface; note that the node cannot normally exceed the edge of the mesh Movement normal to surface With the place node tool highlighted, click-and-drag a node in the graphics area to relocate it. The elements that depend on that node will dynamically adjust as you drag, resulting in a QI change.
allow movement out of boundary	To move the nodes past the edges of a mesh boundary, select this check box. This option is only available when along surface is selected. Movement along surface, allowing movement out of boundary
move midnodes	To move the midnodes associated with the node you are moving, select this check box. This option is useful when you are working with second order elements.

Panel Inputs

Input

Action

radial

Use this option to alter the radius of a hole (and, optionally, the washer).

To alter the radius of the hole, click and drag a node in the graphics area. The element orientation remains constant, but the hole may become larger or smaller based on the input. There are additional controls to enable or disable automatic remeshing when altering the hole dimensions.

qi_hole_radial

radius: (and edit check box)

This field displays the current radius of the hole that the selected node belongs to. By default it is a display-only field.

If you do not want to click and drag a node in the graphics area, you can select the edit check box and specify a desired radius. Once you click a node in the desired hole, the radius will change to the specified value.

angular

Use this option to move the nodes around the edges of the hole without changing the hole diameter or the spacing between nodes.

qi_hole_angular

angle: (and edit check box)

This field displays the current angle of the hole that the selected node belongs to, relative to its original (unmodified) starting position. By default it is a a display-only field.

If you do not want to click and drag a node in the graphics area, you can select the edit check box and specify a desired angle. Once you click a node in the desired hole, the angle will change to the specified value.

radial and angular:

Use this option to simultaneously change the hole's radius and the orientation of nodes around its edge. Like the angular option, the node spacing remains proportionally consistent, though actual spacing will be scaled in accordance with changes in the hole radius.

qi_hole_radialandangular

radial and angular: (and edit check boxes)

These fields display the current angle and radius of the hole that the selected node belongs to. By default they are both a display-only field.

If you do not want to click and drag a node in the graphics area, you can select both edit check boxes and specify a desired angle and radius. Once you click a node in the desired hole, the angle and radius will simultaneously change to the specified values.

circumferential

Use this option to rotate the nodes along the circumference of the slot without altering the hole's size or shape/orientation. This option is primarily used on opening like slots. The capability works on enclosed slots or holes. It is not designed to work on slots with an opening.

qi_cleanup_modholes_circumferential

circumferential (and edit check box)

This field displays the current arc length of the hole that the selected node belongs to. By default it is a display-only field.

If you do not want to click and drag a node in the graphics area, you can select the edit check box and specify a desired arc length. Once you click a node in the desired hole, the arc length will change to the specified value.

link washers

To change the radial or angular position of nodes, as well as drag and scale the washer nodes along with them, select this check box. In order for the link washers option to work, you must select the allow to move fixed and shared nodes check box in page 4 of the quality index panel.


Starting point (no changes made yet)	Link Washers option turned off.	Link Washers option turned on.

retain washer width

Alters the radius of a hole without changing the width of a washer. When this check box is cleared, the radius of the hole and the washer are changed together. This option is only available for radial and radial & angular changes, when the link washers check box is selected.

retain_washer_width_before

Before modifying the washer

retain_washer_width_without

Without retain washer width selected

retain_washer_width_with

With retain washer width selected

remesh number of layers:

To specify the number of washer layers to automatically remesh after you alter the node position, select this check box.

Use the Swap Edge tool to consider the elements to which the edge belongs, and find alternative orientations for it.

qi_cleanup_swapedge_quads

Each time you click an edge in the graphics area, it switches to the next valid configuration. If an edge swap will not improve element quality, a message to that effect displays in the status bar. To force the swap anyways, click the edge a second time. Additional clicks will cycle through the possible edge positions. The number of possible edge positions depends on the types of elements involved.

For a pair of trias, there are two possible positions for their shared edge. For a pair of quads, there are three possible positions. For a quad and a tria, there are six possible positions.

Use the Node Optimize tool to automatically move a selected node to optimize the overall quality of its surrounding elements. The options along surface, normal to surface, and along and normal to surface work exactly as described for the place node tool. The only difference is that node optimize moves the node automatically, while place node requires you to choose the location manually.

To move the midnodes attached to the node you are optimizing, select the with attached midnodes check box. This option is useful when you are working with second order elements.

qi_cleanup_nodeoptimize_start

The mouse indicates the node that will be moved in each of the following examples

qi_cleanup_nodeoptimize_alongsurf

Moving along surface

qi_cleanup_nodeoptimize_normaltosurf

Moving normal to surface

qi_cleanup_nodeoptimize_alongandnormal

Moving along and normal to surface

Use the Element Optimize tool to automatically optimize the shape of the selected element and the elements surrounding it. It is similar to Node Optimize, except that its effects are wider-spread.

To move the midnodes attached to the element you are optimizing, select the with attached midnodes check box. This option is useful when you are working with second order elements.

qi_cleanup_elemoptimize

Use the Smooth cleanup tool to improve element quality in a surface-based mesh. This cleanup tool uses one or more algorithms to adjust node positions to moderate sharp variations in size or quality in adjacent elements, and to adjust the position of the free nodes of the selected shell elements to smooth out variations in element quality and size.

A node of a shell element is free if none of the following statements are true:

•	It is used by an element that was not selected.

•	It is selected as an anchor node.

•	It is attached to an edge, vertex, or meshing fixed point of a surface.

•	It is used by a 1D element (whether or not that element is selected).

•	It is not attached to a surface, but is on a feature line of the mesh of the selected plate or shell elements.

Panel Inputs

The Smooth panel contains the following subpanels and command buttons:

Input

Action

smooth: elements

To indicate the element(s) you want to smooth, click the entity selector and:

•	select the element(s) in the graphics area.

•	select the element(s) from the extended entity selection menu.

anchor: nodes

To anchor a node (for example, you may use an anchor node at a weld site), click the entity selector and:

•	select the node(s) in the graphics area.

•	select the node(s) in the extended entity selection menu.

(mesh algorithm options switch)

Click the first arrow and select one of the following smooth function behaviors:

•

Autodecide calculates the lengths of all of the elements’ edges to find the extreme values. If the ratio of smallest to largest is below a certain threshold, than autodecide will use the shape correcting algorithm. If the ratio of smallest to largest is above a certain threshold, than autodecide will use the size correcting algorithm.

•	Size Corrected moderates variations in element edge size through the mesh using a modified Laplacian over-relaxation that correctly handles a mixture of quad and tria elements.

•	Shape Corrected moderates variations in element aspect ratio through the mesh using a modified isoparametric-centroidal over-relaxation that correctly handles a mixtures of quad and tria elements.

•	QI Optimization adjusts the nodes to the target quality index value that you define in order to reduce the quality index of the selected elements. Selecting QI optimization enables the following:

-	keep nodes on geometry edges smooths nodes on shared edges only by moving them along the edge, and not across.

-	recursive optimization procedure / single optimization procedure specifies whether to run a single smoothing step (single optimization step), or multiple smoothing steps (recursive optimization procedure) until an internal convergence is reached.

For any elements that are not associated to surfaces, Altair HyperMesh infers an approximation to the shape of the surface that most likely produced these elements.

Use the split/collapse edge cleanup tool to split or collapse the edges of elements in your model.

To use the split edge tool, left-click on one edge. Altair HyperMesh splits the elements that share the selected edge in a way that will achieve the optimum quality.

split_edge_tool

To use the collapse tool, right-click on the edge you wish to collapse. Altair HyperMesh collapses the selected edge, as well as any edges that are associated with it.

collapse_edge_tool

Use the drag tria element cleanup tool to drag a tria element to a different location in the model, or out of the model completely.

To use the drag tria element cleanup tool, left-click on a tria element and drag it to a desired location. Altair HyperMesh highlights the selected tria element in pink.

drag_tool

To drag two tria elements together and merge them into one quad element, select the merge trias check box.

drag_tria_element

Merge trias check box selected.

merge_trias_unselected

Merge trias check box unselected.

Use the split quad element cleanup tool to split a quad element into two tria elements.

To split a quad element, left-click on the quad element you wish to split. Altair HyperMesh splits the quad element into two tria elements.

split_quad_tool

Use the combine tria elements cleanup tool to combine two tria elements into one quad element.

To combine two tria elements, left-click on their shared edge. Altair HyperMesh combines the two tria elements into one quad element.

combine_tria_tool

Use the Patch Checker to review "patches" of failed elements, as well as quality results. Each patch contains failed element with layers of elements around it. To increase or decrease the number of layers, click or respectively. To see the next or previous patch, click or respectively.

The Patch Checker displays the comp. QI value, the number of failed elements, and the percent of failed elements in each patch. To reduce the number of failed elements, use the Quality Index cleanup tools. Once you have corrected all of the elements in the patch, you can move on to the next patch. You will no longer be able to display the previous patch, as all elements are corrected.

patch_checking

The following action buttons appear:

Button	Action
QI settings	This button returns to the quality index panel.
Undo	Undoes the most recent edit. Multiple levels of undo are available.
Redo	Redoes the most recently undone edit. Multiple levels of redo are available.
Save failed	Saves all of the elements deemed "failed" to memory. You can then use the extended entity selection menu of any elems selector in another panel to retrieve the list of failed elements and automatically select them.
Abort	Discards all changes and returns to the quality index panel with the mesh unchanged.
Return	Keeps all changes and returns to the quality index panel.

Quality Index Cleanup Tools Secondary Panel

Quality Index Cleanup Tools Secondary Panel

Quality Index Cleanup Tools Secondary Panel

Panel Layout

Subpanels and Inputs

Panel Inputs

Input

Action

along surface / normal to surface

allow movement out of boundary

move midnodes

Panel Inputs

Input

Action

radial

radius: (and edit check box)

angular

angle: (and edit check box)

radial and angular:

radial and angular: (and edit check boxes)

circumferential

circumferential (and edit check box)

link washers

retain washer width

remesh number of layers:

Panel Inputs

smooth: elements

anchor: nodes

(mesh algorithm options switch)

Button

Action

QI settings

Undo

Redo

Save failed

Abort

Return