HyperMesh and BatchMesher

Parameter File Settings

Parameter File Settings

Previous topic Next topic Expand/collapse all hidden text  

Parameter File Settings

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

In the Parameters File Editor define geometry cleanup and defeaturing parameters. These parameters are used to define things such as washer layers around holes, defeaturing pinholes and solid holes, rows of elements along fillets, and many other options.

Each section in the Parameters File Editor can be toggled to show or hide its options via the small triangular arrow (arrowDown-7) to the right of it. Each section represents a specific type of operation, which can be enabled or disabled at several levels.

hmtoggle_plus1greyElement/Import

parameter_editor_targetelementsize

The Element/Import section offers the following parameters:

Parameter

Action

Target Element Size

The desired element size for meshing and optimization.

The element size set here should match the ideal value for min length and max length as defined in the criteria file.  If this does not match, BatchMesher may not be able to produce meshes that adhere to the target quality requirements.

Import Model with Tolerance

The tolerance value to be used while importing the CAD model. Set this to auto to automatically calculate the tolerance based on the type and dimensions of the model.

 

hmtoggle_plus1greyMidsurface

In the Midsurface section, the Extract midsurfaces parameter determines if a midsurface should be automatically extracted when BatchMesher detects a thin solid geometry. The midsurface is created by offsetting one of the sides of the solid. This functionality is only appropriate for stamped parts - not for machined or molded parts or castings. The resulting midsurface geometry will be batch meshed, while the original geometry will be ignored. When this parameter is active, the Sheet metal only option becomes enabled.

parameter_editor_midsurfacesection

When Sheet metal only is activated, the following options specific to sheet metal midsurface extraction become enabled:

Option

Action

Maximum thin solid thickness to width ratio

This is the maximum ratio between the approximate thickness of the thin solid part (shortest dimension) and its approximate width (2nd shortest dimension).  This parameter is used to limit the midsurface extraction to parts for which the thickness is clearly smaller than the length and width.

Maximum thin solid thickness

Midsurface extraction ignores thin solids with thickness less than this value.

Minimum feature angle between the solid’s edge and its faces

The minimum angle used to distinguish top and bottom faces of a thin solid from its sides.  Angles less than this will be treated as if they were flat for purposes of midsurface extraction.

 

hmtoggle_plus1greyGeometry Cleanup

The Geometry Cleanup section enables BatchMesher to perform a variety of geometry feature recognition and preparation tasks. The Geometry  Cleanup parameter is one of the main functions of BatchMesher and is turned on by default. You can choose to turn off this parameter if you have already performed manual geometry cleanup and only wish to mesh the part. When Geometry Cleanup is activated, the following cleanup parameters, that can be turned on and off independently, become enabled:

parameter_editor_surfaceholerecognition

When Surface hole recognition is activated, surface holes of different sizes are recognized and treated appropriately. A table becomes enabled to define the radii ranges and additional options:

Option

Action

Add Line (addnewrow)

Adds an empty row to the end of the table.

Delete Line (removerow)

Removes the selected row from the table.

R<

The maximum radius of the current hole range. The minimum value is taken as 0.0 for the first row, or as the maximum value from the previous row.

Range

The radius range for the current row.  This value is read-only.

Mark center

Option to create a node and tag at the center of the hole, or to do nothing.

Remove

Remove (defeature) the hole. If Remove is disabled, the following options are available:

Target radius

Holes in the range are adjusted to have the specified target radius.  The radius can be specified as an exact value (for example 5.0), or as an expression based on the original radius (for example radius*1.1, radius-0.5, radius+0.5).

# elems

Specifies the minimum/exact number of elements to create around the holes.

Elems mode

Defines whether # elems defines the minimum or exact number of elements.

Washer

Option to create washer layers around holes. If specified, one or two layers can be created.

-1st washer

Specify the width of the first washer as a constant value (select the blank entry in the drop down and enter a value), a scale of the hole radius (for example 0.6*radius), or an automatic determination based on element quality.

-2nd washer

Specify the width of the second washer as a constant value (select the blank entry in the drop down and enter a value), a scale of the hole radius (for example 0.6*radius), or an automatic determination based on element quality.  If the value is left blank, no washer will be used.

-Priority

Sets the priority of one radii range over the others.  For example, if you wish to ensure all bolt holes (radii 10-15) have correct washers but other holes are not critical, holes with radii 10-15 will receive higher priority than others.  This ensures that if two holes close to each other in the model have overlapping/conflicting washers, the hole with higher priority gets the washer while the other does not.

 

parameter_editor_usefileforholerecognition

When Use file for hole recognition is activated, you are provided a file containing X, Y, Z center locations of all of the holes to consider. BatchMesher compares these locations to the holes in the job’s models, and prioritizes the holes that match.  All of the options for Surface hole recognition are available for these holes. If one or more holes files are defined, BatchMesher looks for the found holes in each file.  If found, it applies the washer table linked to the file to the corresponding holes.  If a hole is not found in any file, the settings from the default surface holes table are used.

Multiple files can be specified, each with their own definitions. The order of the files determines the order of precedence in the case where there are overlapping or conflicting definitions.

Add table

Adds a new table for creating a new hole file.

Delete table

Deletes the specified hole file table.

 

The holes file must contain one line for each hole, with the values either space, tab or comma separated.  Each line contains a line number followed by the X, Y, Z locations of each hole center.  For example, using spaces/tabs with line numbers:

1 1420 -839 65

2 1724 -846 212

3 1683 -845 265

4 1660 -841 308

 

Or using commas with line numbers:

1,1420,-839,65

2,1724,-846,212

3,1683,-845,265

4,1660,-841,308

 

parameter_editor_solidholerecognition

When Solid hole recognition is activated, solid holes (cylindrical surfaces in volumes) of different sizes are recognized and treated appropriately. A table becomes enabled to define the radii ranges and additional options:

Option

Action

Add Line (addnewrow)

Adds an empty row to the end of the table.

Delete Line (removerow)

Removes the selected row from the table.

R<

The maximum radius of the current hole range.  The minimum value is taken as 0.0 for the first row, or as the maximum value from the previous row.

Range

The radius range for the current row.  This value is read-only.

Mark center

Option to create a node and tag at the center of the hole, or to do nothing.

Remove

Remove (defeature) the hole.  If Remove is disabled, the following options are available:

# elems Specifies the minimum/exact number of elements to create around the holes.

 

parameter_editor_surfacefilletrecognition

When Surface fillet recognition is activated, fillet surfaces are recognized to be able to perform one or more of the following options:

Prevent the main (long) edges of the fillets from being suppressed and also prevent the nodes of those edges from moving while fixing element quality
Specify the number of elements across the width of the fillets for given fillet radii
Specify the chordal deviation to be achieved while meshing

 

parameter_editor_flangerecognition

When Flange recognition is activated, geometry that represents flanges on sheet metal parts is recognized and the following options become enabled:

Option

Action

Elements across flange width

The minimum number of elements to be created across the flange width.

Maximum width of flange

The maximum flange width to consider for flange recognition.

Minimum width of flange

The minimum flange width to consider for flange recognition.

Delete flange narrow surfaces with width <

Controls the removal of narrow flange surfaces to avoid creation of sliver elements.

Auto

Maximal narrow surface width is the minimum of 0.2*element_size and min_element_size.

<value>

A user input value defining the maximal narrow surface width to remove.

flange_narrow

arrow

flange_narrow_1_after

Flange narrow surface removal

 

parameter_editor_otheroptions

When Other Options is activated, the following options become enabled:

Option

Action

Delete duplicated surfaces

Options for deleting duplicate surfaces before meshing.  Duplicates are determined using several options.

All

All surfaces in all components are considered against each other to find duplicates.

Within components only

Finding of duplicate surfaces between components is not allowed.

None

No duplicate surface removal is performed.

 

The with tolerance option defines the tolerance used when finding duplicates.  It is defined in one of two ways:

Auto

The tolerance is automatically calculated from the model size and other relevant geometric parameters.

<value>

A user input value. This is more useful when the auto tolerance is not sufficient to find all of the duplicates.

Edges equivalencing with tolerance <

This defines the tolerance to use for equivalencing (stitching) edges, in conjunction with the options below.  The auto option calculates the tolerance internally, while manual setting of the tolerance may be more useful when the auto tolerance is not sufficient to make all of the necessary connections.

Allow T-connections

T-connections (non-manifold edges) are allowed to be created during the stitching process.

Within components only

Stitching between edges of different components is not allowed.

Apply aggressive stitching

Additional heuristic procedures for finding cracks and stitching of them with an increased auto-defined tolerance are applied.  This is useful for models that may be significantly "dirty", for  example when midsurfacing does not do a good job.

Fix overlapped surfaces with tangency angle <

This option gives you control of the embedded geometry cleanup tool and allows you to fix overlapping surfaces.

Auto

Automatically calculates the tangency angle internally.

<value>

Enter a maximal tangency angle to fix overlapped surfaces.

overlappedsurfacestangencyangle

arrow

overlappedsurfacestangencyanglefixed

Overlapped surfaces fixed

Note:This option may remove the surfaces that should not be deleted. For example, it may happen to surfaces with T-connections.

fixed overlapped surfaces

Possible side effects of fixing overlapped surfaces.

Suppress narrow fillets and surfaces with width <

This defines the width below which narrow fillets and surfaces are suppressed.  The default "auto" value is about 1.2 * minimal element size (except in the case of sharp features which are kept even with a width a bit less than the minimal element size).  This value can be tuned to better match the mesh to the topology as needed.

Recognize main fillet strips

Controls the recognition of wide fillet strips that are significantly bigger than the fillet merging threshold.  These fillets often contain narrow fillets.  This option aims to preserve the main fillets while suppressing the narrow ones.  The side effect is that more narrow fillets close to the minimum element size are not merged.

and preserve main edges

For wide fillets, we try to recognize the "main" boundary lines – the edges that are the boundary of large flat surfaces.  To preserve these edges from suppression and to prevent the movement of nodes off of them by element cleanup and smoothing, these edges are specially marked with this option.  The side effects are that generally the element quality worsens because of the introduction of new "hard" features.  This is especially true when there are sliver elements between two feature lines which will no longer allow element cleanup to collapse them due to enabling this option.

Suppress beads with height <

Turns on bead recognition and suppresses any beads with a height less than the specified value.

Preserve rounded bead midline

Enforces node placement along the midline of a rounded bead.

Suppress flanged holes with height <

Holes with small downward flanges are recognized and those with a height less than the specified value are eliminated.

Remove edge fillet with radius <

Removes any fillets/rounded edges located on free edges and having radii below the specified value.

Remove logo

Removes small geometric features that represent company logos from the model design. The following parameters are used to define and remove logos:

with size <

The maximal size of a letter in the logo, as measured along/parallel to the "shiny" surface.

and height <

The maximal height/depth of a letter in the logo, as measured normal to the "shiny" surface.

Concavity factor

Creates a filter that provides more flexible control of automatic logo recognition.

Note:This tool is heuristic and may remove real features (such as flat bottom round dimples) that were not intended for removal.

The Concavity factor is a quantitative measure of a letters shape complexity, formally defined as:

concavityfactor

The contour_accumulated_turn_angle is the sum of angles between a letters contour straight parts. Curved parts of a contour letter are approximated by a segmented line composed of short straight segments. For completely concave contour (such as circles, quads, and hexagons) concavity factor contour_accumulated_turn_angle = 360 degrees and concavity factor = 0.

To extend the recognition and removal of a logo, the Concavity factor should be reduced.

 

Logo_test

Logo removal parameters

Remove threads with depth <

Removes cylindrical or conical threads with a depth less than the specified value, and replaces them with a smooth cylinder or cone surface. The following options are used to define the diameter of the replacing cylinder or cone:

autodecide

BatchMesher will select the diameter of the replacing cylinder based on the diameter of a blank before thread cutting begins:

-For inner (hole) threads, it corresponds to the thread minor diameter.
-For outer (bold) threads, it corresponds to the thread major diameter.
major

The replacing cylinder or cone will have the thread major diameter.

mean

The replacing cylinder or cone will have the thread mean diameter.

minor

The replacing cylinder or cone will have the thread minor diameter.

threadremovalparamteres

Thread removal parameters

 

 

hmtoggle_plus1greyComponent Boundary

parameter_editor_preserveboundaries

The Component Boundary section offers one parameter, Preserve boundaries between components. When this parameter is enabled, it defines that components' boundary edges are not allowed to be suppressed or removed in geometry cleanup, and elements nodes are not allowed to be moved across the components' boundaries. In some cases, maintaining boundaries for adjacent components that do not have any structural meaning would significantly worsen the element quality results.

 

hmtoggle_plus1greyCreate Mesh

The Create mesh with element type parameter allows BatchMesher to generate a mesh on the cleaned-up geometry. This is one of the main functions of BatchMesher and is turned on by default. You can choose to turn off this parameter if you only want to perform geometry feature recognition and cleanup without meshing.

parameter_editor_createmeshwithelementtype

When Create mesh with element type is activated, the following options become enabled:

Option

Action

Element Type

The type of elements to create: mixed, quad or tria.

mesh flow

align

Produces a more orthogonal quad dominated mesh.

size

Enforces the global mesh element size with minimal min/max element size variation.

Element order

Defines whether to create first or second order elements.

Place elements in

New elements can be organized in either the current component or the original surfaces’ component(s).

Apply tria reduction

Determines whether or not to use global tria reduction. min elem size > and max size < are minimal and maximal elements sizes allowed for fragments of a mesh that will be remeshed by the removal of trias.  Usually these parameters are more restrictive than those given by the criteria settings, to provide a more uniform mesh after applying the tria reduction procedure.

Apply optimized smoothing

After the surfaces are appropriately meshed, the nodes are optimized towards a target smoothing value to improve the element quality while maintaining geometry features. This smooth target value is a composite Quality Index rating, ranging from 0 (perfect elements) to 1.0 (failed elements).  The default of 0.2 is ideal for most cases, producing elements of good quality without taking too long to optimize, but can be altered if necessary.

none

No smoothing is performed.

within surfaces

Only nodes within surfaces are smoothed.  Nodes on surface edges are not moved.

along edges

Smooths nodes both within a surface and along edges.  Nodes on edges are allowed to move only along the edge to improve element quality.

across edges

Smooths nodes both within a surface and across edges.  Nodes on edges are allowed to move both along and across the edge to the neighboring surface to improve element quality.

-Apply failed features cleanup

When on (default), element cleanup will ignore geometry features when fixing elements failing the quality threshold.  When off, element cleanup will skip failed feature cleanup, which could sacrifice element quality in order to better capture the features.  Note that fixing of features is still possible using the "Correct features" option.

Correct features

Move across shared edges, max dist <

Allows the nodes to move a certain distance across or away from the geometry shared edge by less than the predefined distance.

Move across free edges, max dist <

Allows the nodes to move a certain distance across or away from the geometry free edge by less than the predefined distance.

Correct warped elements

Offset nodes from surfs, max dist <

Allows the nodes to move off the surface to meet the warpage criteria defined in the criteria file.  The distance specified is the max distance the nodes can move off the surface.

Divide quads into trias

Allows quads to be split into trias to meet certain element criteria as defined in the criteria file.

Feature angle during element cleanup

The minimum angle to be maintained (rather than flattened) while performing element cleanup.

Folding angle

Elements whose angle exceeds this value are considered folded over, and BatchMesher attempts to clean them up.

 

hmtoggle_plus1greySpecial Component Selection

parameter_editor_specialcomponentselection

When Special component selection is activated, the following options become enabled:

Option

Action

Mesh selected components without geometry cleanup

BatchMesher will mesh the listed components but will not perform any geometry cleanup on them before meshing.  Any remaining components that are not listed will be batch meshed using the normal process, including geometry cleanup.

This is useful for models in which some components do not require geometry cleanup but the rest might.  (Models in which no components require cleanup can be batch meshed with the Geometry Cleanup checkbox turned off.)

Mesh selected components while maintaining connectivity to external mesh

BatchMesher will mesh the listed components while maintaining connectivity to any existing mesh.

This is useful when components are to be meshed with multiple element sizes but transitions at the common edges of the different sizes are required.  Each component should be meshed individually with its own parameter and criteria files with this option enabled.

Ignore selected components while maintaining connectivity to meshed components

BatchMesher will ignore the listed components while maintaining connectivity to any existing mesh.  The mesh and geometry of the ignored components are not touched during batch meshing.  The mesh created on other adjacent components is connected to any existing mesh on the ignored components.

This is useful for batch meshing of different components with different criteria/parameters files, or when pre-meshing components interactively or with some other procedure, followed by batch meshing of other components.

addnewrow

Adds the name of a component specified in the drop down to the table.  To provide a new name, select the empty entry in the drop down and type a new name.

removerow

Removes the selected row from the table.

 

As an example, a model may have two components named front_10 and rear_20, which share common surface edges.  The component front_10 is to be meshed with element size 10 and rear_20 with element size 20.  This can be accomplished as follows:

1.Create two sets of parameter/criteria files.
The first should have a target element size of 10 and the appropriate parameters.  In this parameter file, turn on the Special component selection option, Mesh selected components while maintaining connectivity to external mesh sub-option, and list front_10 in the component list.
The second file should have a target element size of 20 and the appropriate parameters. In this parameter file, turn on the Special component selection option, Mesh selected components while maintaining connectivity to external mesh sub-option, and list rear_20 in the component list.
2.Create a mesh type and assign the first set of criteria and parameter files.
3.Create a second mesh type with the same name as the first, and assign the second set of criteria and parameter files.
4.Choose the geometry file to be batch meshed, assigning it the mesh type from above, and submit the job.

This will mesh front_10 first with the first mesh type, and then take the results of this and mesh rear_20 with the second mesh type, while maintaining connectivity with the mesh created on front_10.