Engineering Solutions

Automeshing Secondary panel

Automeshing Secondary panel

 Previous topic Next topic Expand/collapse all hidden text  

Automeshing Secondary panel

 Previous topic Next topic JavaScript is required for expanding text JavaScript is required for the print function  

Use the Automeshing Secondary panel to create meshes interactively on surfaces, or even without a surface present. It serves as the unified secondary panel for most of the plate and shell meshing panels; using those panels gives you access to this Automeshing Secondary panel. In the Automeshing Secondary panel you can interactively adjust a wide variety of parameters and choose from a suite of algorithms.  Engineering Solutions responds with immediate feedback on the effects of the changes, until you are satisfied with the resulting mesh.

There are two approaches to automatic mesh generation, depending on whether or not you use surfaces as the basis for the operation.

•If you use surfaces, you may choose from a greater variety of algorithms, have more flexibility in specifying the algorithm parameters, and employ the mesh-smoothing operation to improve element quality.
•If you do not use surfaces, the meshing process is usually faster and uses less memory.  Most of the functions are still available and operate in the same way.  Furthermore, there are situations in which it is not possible or not desirable to create a surface.

For either approach, the panel operates the same. You control interactively the number of elements on each edge or side, and can determine immediately the nodes that are used to create the mesh. You can adjust the node biasing on each edge to force more elements to be created near one end than near the other, which allows you to immediately see the locations of the new nodes. You can also specify whether the new elements should be quads, trias, or mixed and whether they should be first or second order elements. The created mesh can be previewed, allowing you to evaluate it for element quality before choosing to store it in the database. While you are in the meshing module, you can use any of viewing tools on the visual options menu to simplify the visualization of complex structures in your model.

HMUG_bmp00097

A solid model created by dragging automeshed plate elements.

HMUG_bmp00106

The Automesh Secondary panel can make second order elements for boundary element solutions.

Panel Usage

This panel shows the pre-generated mesh from its preceding Automesh subpanel, and provides tools to adjust the mesh before finalizing it.

While you are using the Automeshing Secondary panel, the function keys are disabled and you cannot change the element order on the Options panel.

As a secondary panel dependent on the subpanel that activates it, the changes you make are only applicable to the current meshing action. Leaving the secondary panel will render its settings irrelevant since the only means of return is to restart meshing from one of the Automesh subpanels.

•Set the secondary panel mode by selecting the appropriate subpanel
•Use the criteria presented by the subpanel to alter the final mesh outcome
•Click the mesh button to finalize the mesh, reject to abort, or smooth to automatically improve the mesh quality.

 

Subpanels and Inputs

The Automeshing Secondary panel contains the following subpanels and command buttons:

hmtoggle_arrow1Density

Use the density subpanel to change the node density along a specified edge or edges.      

 

Panel Inputs

Input

Action

adjust: edge

When this collector is highlighted, you can left-click an edge to increase the number of nodes along it, or right-click to decrease the number.  In addition, the number displays the current node density; click-and-drag on the number to increase or decrease it.

calculate: edge

This works in conjunction with the elem size setting.  With this collector highlighted, any edge that you click will be set to the necessary density to support the specified element size.

calculate: recalc all

Sets all edges to the number of nodes necessary to support the element size specified in elem size.

elem size =

Use this numeric text box to specify the desired element size for edges.  You can then use claculate: edge or calculate: recalc all to set edges to the necessary nodal density to support this element size as well as possible.

Note:This will be a "best fit" calculation, as it is unlikely that the selected edge will be exactly the right length for the specified element size.

link opposite edges

Any changes applied to one linked edge will be applied to the opposite edge of simple chains when edges are clicked.

set: edge

When highlighted, clicking an edge sets its nodal density to the value required by elem density.

set: set to all

Sets all edges to the nodal density required by in elem density.

elem density

Specifies a required number of elements to lie on the edge, producing a number of nodes one greater than this value.

Local View

The local view pop-up menu contains tools that are customized for use in the Automeshing Secondary panel.  Many of the display options are similar to those found on the View menu accessed from the toolbar.  All the options orient the view, keeping the current surface centered in the window.  You may also choose to suppress the display of nodes and elements.

Location:density, algorithm, type, biasing, details, and checks subpanels of the Automeshing Secondary panel.

local_view1

Local view pop-up menu (regular version)

The details and checks subpanels contain an expanded local view pop-up menu with additional tools. Use these tools to change the view with the focus staying centered on the highlighted face. You may also suppress the display of nodes or elements separately for the highlighted face and for the remaining faces of the surface.

local_view2

Local view pop-up menu (expanded version)

The options on the local view menu are summarized below:

cw, ccw

Rotates the view clockwise or counterclockwise around the center of the surface, ignoring everything else in the Engineering Solutions database.

left,  right, top, bottom, rear, front

Sets the view to look from that direction, and then fills the screen with the surface.

fill surf

Sizes the selected surface to fill the screen.

elemts, nodes, all nodes

Controls the display of elements and nodes.

 

Comments        

The ability to hide elements of other faces is particularly useful when you have a complicated surface with several faces and the some surfaces are interfering with your view.

Alternatively, it is sometimes helpful to display all the elements of the other faces and hide those of one face.  In this way, you can look inside a complicated object.

•With the  collector highlighted, you can click an edge to set its node density to the number appropriate to the specified element size. Alternatively, click recalc all to set all edges to the specified density.
•With the set: edge collector highlighted, click an edge to set its node density to a specific number. This differs from calculate: edge only in that it lets you specify the node density, instead of specifying the element size (which determines the node density indirectly as #elems+1).

 
hmtoggle_arrow1Mesh Style

Use the Mesh Style subpanel to specify the meshing algorithm to use for each face of each domain when you are following a surface-based approach. The shape of the icon on each face identifies the algorithm that has been specified for that face.

This subpanel lets you change the mesh style (quads, trias, mixed) for individual, specific surfaces.

•Toggle a surface to cycle through element types: tria, quad, mixed, right-tria, or quad-only.
•Toggle a surface to cycle through mesh mapping methods: autodecide, rectangle, triangle, pentagon, circle, free (unmapped).
•Set a surface, or all surfaces, to use any combination of options: align flow, size control, skew control, or automatic smoothing

 

Panel Inputs

Input

Action

elem type: toggle surf

When this button is highlighted, the element type used on each surface displays as an icon in its center.  Clicking the icon cycles through the available types: tria, quad, mixed, right-tria, or quad-only:

mesh_type_icons

set surf

When highlighted, this button works in conjunction with the element type selected from the switch below it, setting any surface that you click to the element type specified in the switch.

set all

This button works in conjunction with the element type selected from the switch below it, setting all visible surfaces to the element type specified in the switch.

quads / trias / mixed / r-trias / quads only

(switch)

Use this switch to pick an element type that you wish to apply to some (set surf) or all (set all) surfaces.

mesh_type_trias

Trias

mesh_type_mixed

Mixed (density 10 at top,
density 5 at bottom)

mesh_type_quads

Quads

mesh_type_right_trias

Right-trias

mesh_type_quadsonly

Quads-only (density 10
at top, 5 at bottom)
Note:In certain cases quads may still use a small number of tria elements when the mesh quality using only quads would not be acceptable. Quads only never uses trias, regardless of the resulting mesh quality.
 
If you use the mixed (quads and trias) element type, the automesher uses a modified map as rectangle meshing scheme.  The modification makes transitions between differing element densities through the use of triangles as shown below.  This tends to produce mesh patterns that are more regular in appearance, as shown in the bottom image below:

triatrans

mesh method: toggle surf

When this button is highlighted, the meshing method used on each surface displays as an icon in its center.  Clicking the icon cycles through the available mapping types: autodecide, rectangle, triangle, pentagon, circle, or free:

mesh_map_method_icons

mesh method: set surf

When highlighted, this button works in conjunction with the mesh method selected from the switch below it, setting any surface that you click to the element type specified in the switch.

mesh method: set all

When highlighted, this button works in conjunction with the mesh method selected from the switch below it, setting all surfaces to the element type specified in the switch.

autodecide /
map as rectangle /
map as triangle /
map as pentagon /
map as circle /
free (unmapped)

(switch)

This sets how the mesh will be mapped to the surface based on the surface's general overall shape.

mesh_map_array_auto

Note:When using autodecide, the mesh mapping method will change automatically to one of the other types after clicking the mesh button. This is because autodecide literally chooses the best option from the other types before the mesh is applied.
 
Even if you do not use autodecide, the meshing engine may change the mapping method if it is clearly inappropriate for the surface being meshed.  For example, it will not apply triangular mapping to a uniformly square surface, but instead will change the mapping method to triangular.

set: set surf

When highlighted, this button works in conjunction with the various options listed below it, setting any surface that you click to use the options specified.

set: set all

When clicked, this button works in conjunction with the various options listed below it, setting all surfaces to use the options specified.

to use: flow: align

Produce a more orthogonal quad-dominant mesh. Only applies to mixed element type.

automesh_noFlowControl2

Here, there is no flow alignment

automesh_FlowControl2

Flow alignment is used, producing straighter rows of elements

to use: flow: size

Appears only when align is active, and enforces the global mesh element size with minimal variation from the min/max element size.

to use: map: size

Keeps the elements roughly the same size.

to use: map: skew

Prevents the mesh from producing highly-skewed elements.

to use: smoothing

Performs an automatic cleanup pass on the generated mesh in an effort to improve the overall element quality.

local view

The local view pop-up menu contains tools that are customized for use in the Automeshing Secondary panel.  Many of the display options are similar to those found on the View menu accessed from the toolbar.  All the options orient the view, keeping the current surface centered in the window.  You may also choose to suppress the display of nodes and elements.

Location:density, algorithm, type, biasing, details, and checks subpanels of the Automeshing Secondary panel.

local_view1

Local view pop-up menu (regular version)

The details and checks subpanels contain an expanded local view pop-up menu with additional tools. Use these tools to change the view with the focus staying centered on the highlighted face. You may also suppress the display of nodes or elements separately for the highlighted face and for the remaining faces of the surface.

local_view2

Local view pop-up menu (expanded version)

The options on the local view menu are summarized below:

cw, ccw

Rotates the view clockwise or counterclockwise around the center of the surface, ignoring everything else in the Engineering Solutions database.

left,  right, top, bottom, rear, front

Sets the view to look from that direction, and then fills the screen with the surface.

fill surf

Sizes the selected surface to fill the screen.

elemts, nodes, all nodes

Controls the display of elements and nodes.

 

Comments        

The ability to hide elements of other faces is particularly useful when you have a complicated surface with several faces and the some surfaces are interfering with your view.

Alternatively, it is sometimes helpful to display all the elements of the other faces and hide those of one face.  In this way, you can look inside a complicated object.

 
hmtoggle_arrow1Biasing

Use the Biasing subpanel to apply linear, exponential, or bellcurve biasing to individual edges of a surface.

•Left-click an edge to increment its bias, or right-click to decrement it.
•Click-and-drag on the displayed bias factor to raise or lower it.

HM_Panels_bmp00013

This mesh was generated without the use of element biasing. Note the poor aspect ratios of the elements in the lower right-hand corner.

HM_Panels_bmp00014

Biasing the elements along the top and bottom edges improves angles and aspect ratios.

 

Panel Inputs

Input

Action

adjust: edge

Click the edge collector, then click the desired edge, to increment or decrement the biasing factor for that edge.  Alternatively, you can click-and-drag the numerical biasing value shown for the edge; dragging upwards increases and dragging downwards decreases.

biasing_adjust_edge

calculate: edge

Click the corresponding edge collector, then click the desired edge, to set that edge's biasing factor to the value specified in intensity (below).

revert: edge

Click the corresponding edge collector, and then select the desired edge to revert it in the opposite direction.

recalc all

Sets all edges to the biasing factor specified in intensity (below).

intensity =

Type in a biasing factor. This will be applied to any edge selected via the calculate: edge option, or to all edges upon clicking recalc all.

link opposite edges

Any changes applied to one linked edge will be applied to the opposite edges of simple chains when edges are clicked.

set: edge

Click the desired edge's biasing indicator to change its to use the currently selected bias style (described below).  Biasing indicators display when either this collector or the set all to button are clicked.

Biasing indicators are:

•biasing_indicator_linear Linear
•biasing_indicator_exponential Exponential
•biasing_indicator_bellcurve Bellcurve

set all to

Sets all edges to use the currently selected bias style (described below).

bias style

Use this switch to choose between linear, exponential, or bellcurve biasing.

bias_style_example

local view

The local view pop-up menu contains tools that are customized for use in the Automeshing Secondary panel.  Many of the display options are similar to those found on the View menu accessed from the toolbar.  All the options orient the view, keeping the current surface centered in the window.  You may also choose to suppress the display of nodes and elements.

Location:density, algorithm, type, biasing, details, and checks subpanels of the Automeshing Secondary panel.

local_view1

Local view pop-up menu (regular version)

The details and checks subpanels contain an expanded local view pop-up menu with additional tools. Use these tools to change the view with the focus staying centered on the highlighted face. You may also suppress the display of nodes or elements separately for the highlighted face and for the remaining faces of the surface.

local_view2

Local view pop-up menu (expanded version)

The options on the local view menu are summarized below:

cw, ccw

Rotates the view clockwise or counterclockwise around the center of the surface, ignoring everything else in the Engineering Solutions database.

left,  right, top, bottom, rear, front

Sets the view to look from that direction, and then fills the screen with the surface.

fill surf

Sizes the selected surface to fill the screen.

elemts, nodes, all nodes

Controls the display of elements and nodes.

 

Comments        

The ability to hide elements of other faces is particularly useful when you have a complicated surface with several faces and the some surfaces are interfering with your view.

Alternatively, it is sometimes helpful to display all the elements of the other faces and hide those of one face.  In this way, you can look inside a complicated object.

 
hmtoggle_arrow1Checks

Use the Checks subpanel to use the functions of the Check Elements panel on a newly-generated mesh before storing it in the database. The tests are the same as on the Check Elements panel, and elements that fail a quality test are highlighted in red. Only displayed elements are tested; the display of elements is controlled by the local view panel. The Checks subpanel operates on a by-face method. The active highlighted face serves as a frame of reference for meshing, smoothing, and display operations. To select another face, select the face’s icon in the graphics area.

In this subpanel, you can specify minimum or maximum values for element quality criteria according to several measures. The final mesh will attempt to adhere to the requirements set on this panel by producing elements that do not violate these quality criteria.

The criteria includes warpage, aspect, skew, min angle and max angle (quads only), length, jacobian, and min angle/max angle (trias only).

This subpanel also includes a button to access the local view dialog.

The local view pop-up menu contains tools that are customized for use in the Automeshing Secondary panel.  Many of the display options are similar to those found on the View menu accessed from the toolbar.  All the options orient the view, keeping the current surface centered in the window.  You may also choose to suppress the display of nodes and elements.

Location:density, algorithm, type, biasing, details, and checks subpanels of the Automeshing Secondary panel.

local_view1

Local view pop-up menu (regular version)

The details and checks subpanels contain an expanded local view pop-up menu with additional tools. Use these tools to change the view with the focus staying centered on the highlighted face. You may also suppress the display of nodes or elements separately for the highlighted face and for the remaining faces of the surface.

local_view2

Local view pop-up menu (expanded version)

The options on the local view menu are summarized below:

cw, ccw

Rotates the view clockwise or counterclockwise around the center of the surface, ignoring everything else in the Engineering Solutions database.

left,  right, top, bottom, rear, front

Sets the view to look from that direction, and then fills the screen with the surface.

fill surf

Sizes the selected surface to fill the screen.

elemts, nodes, all nodes

Controls the display of elements and nodes.

 

Comments        

The ability to hide elements of other faces is particularly useful when you have a complicated surface with several faces and the some surfaces are interfering with your view.

Alternatively, it is sometimes helpful to display all the elements of the other faces and hide those of one face.  In this way, you can look inside a complicated object.

 
hmtoggle_arrow1Command Buttons

The following action buttons appear throughout the subpanels:

Button

Action

mesh

Scans through all of the faces in the current frame of reference for ones that have not yet been meshed or have a mesh that is out of date with respect to the user-specified parameters, and then attempts to bring them up to date. If the current subpanel is density, mesh style, type, or biasing, the current frame of reference is the entire surface.  If the current subpanel is details or checks, the current frame of reference is the highlighted face.

reject

Discards a generated mesh of one selected face or of all of the faces of the current domain.

smooth

Applies a mesh smoothing algorithm to each face in the current frame of reference.  This button does not appear in the checks subpanel.

undo

Returns the nodes on the mesh to the positions they were in before the last time you applied a smooth to that mesh for each face in the current frame of reference. Not available in the checks subpanel.

abort

Immediately exits the Automeshing Secondary panel without saving any elements or nodes to the database.  If the module was entered from a surface creation panel, any surface that may have been created is discarded.

return

Exits the Automeshing Secondary panel, saving elements or nodes to the database.