Parameter Settings

Geometry cleanup behaviors and options provide excellent feature capture with more user control resulting in more predictability, consistency and ease of use.

Batchmesher recognizes classified features like beads, dimples, flat bottom bosses/depressions, flanges, fillets, holes (2d and 3d), and so on. These features are treated following user defined criterias, allowing the preservation of the main feature edges providing excellent feature capture.

Controlling the above parameters can result in good feature capture with minimum quality index failures. However, features are given more importance which might increase the failed element count based on geometry and the cleanup parameter values. It is important to define all of the settings appropriately.

Select the Geometry cleanup checkbox to enable additional cleanup parameters that can be turned on and off independently.

Surface Hole Recognition

Figure 4.

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.

Surface hole recognition table data

Define radii ranges and additional options in the table. Click to add a row to the table, or click to remove a row from the table.

Table 1. Surface Hole Recognition Table Data

Column	Action
R<	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. For slotted holes, the radius is measured at the tip of the hole.
Range	Radius range for the current row. This value is read-only.
Mark center	Create a node and tag at the center of the hole, or do nothing.
Remove	Remove (defeature) the hole. For slotted holes, the hole is removed only if the tip radius is less than the specified radius threshold, and the length of the hole is less than 1.4 times the target element size. If Remove is disabled, additional options are available.
Target radius	Adjust holes in the range 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	Enter the minimum/exact number of elements to create around the holes, or set to auto to automatically select the number of elements so that the min and max element size requirements are satisfied, with the best possible representation of the hole shape. Tip: Auto is not recommended for holes with washer layers.
Elems mode	Choose whether # elems setting defines the minimum or exact number of elements.
Washer	Create washer layers around holes. If specified, one or two layers can be created.
1st washer/2nd washer/3rd washer	Sets the width of the first, second, third 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, a subtraction formula, for example 14.0-radius, or an automatic determination based on element quality.
Priority	Set the priority of one radii range over the others. For example, 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, or the hole with the lower priority may get a modified washer instead. In addition, when a hole is set to high priority, washer elements are not modified to correct for failed element quality. If a hole is set to normal priority, washer nodes are allowed to move to correct the quality.

Attempt to maintain narrow slot rounded ends using >=6 elements

Attempt to generate a mesh using the pattern indicated in Figure 5.

Figure 5.

Clear this checkbox to attempt to generate a mesh using the pattern indicated in Figure 6, which has six elements, two on each long side and one on each end.

Figure 6.

Add circumferencial trim lines for washer

Keep geometry trim lines for washers.

Figure 7. Add circumferencial trim lines for washer - Off	Figure 8. Add circumferencial trim lines for washer - On

Suppress flanged holes with height <

Recognize holes with small downward flanges and eliminate those flanges with a height less than the specified value. Flanges with a height less than the minimal element size are extended to the minimal element size if not removed.

Use File for Hole Recognition

Figure 9.

Select Use file for hole recognition to provide a file containing X, Y, Z center locations of all of the holes to consider. This is useful for special treatment of specific holes, usually bolt holes.

Batchmesher compares the defined locations to the holes in the model, 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, in the order the files are defined. If found, it applies the washer table linked to the first found file to the corresponding holes. If a hole is not found in any file, the settings from the default general 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.

Click Add table to add a new table for creating a new hole file. Click Delete table to delete the specified hole file table.

1 1420 -839 65
2 1724 -846 212
3 1683 -845 265
4 1660 -841 308

1,1420,-839,65
2,1724,-846,212
3,1683,-845,265
4,1660,-841,308

Solid Hole Recognition

Figure 12.

Select Solid hole recognition to recognize and treat solid holes (cylindrical surfaces in volumes) of different sizes. A table becomes enabled to define the radii ranges and additional options.

Click to add a row to the table, or click to remove a row from the table.

Table 2. Solid Hole Recognition Table Data

Column	Action
R<	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	Radius range for the current row. This value is read-only.
Mark center	Create a node and tag at the center of the hole, or to do nothing.
Remove	Removes (defeature) the hole. If Remove is disabled, you must specify the minimum/exact # elems to create around the holes.

Surface Fillet Recognition

Figure 13.

Select Surface fillet recognition to recognize surface fillets in order 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.
• Remove/defeature fillets. Gaps may result if complicated fillets cannot be removed.
• Split the fillets along the mid-line and suppress the edges.
• Specify the number of elements across the width of the fillets for given fillet radii.
• Specify the chordal deviation to be achieved while meshing.

A table becomes enabled to define a desired number of element rows for specific ranges of average fillet radii, width, or both. The width value is defined is the arc length of the fillet.

In Figure 14, uniform fillet strips with an average radius between 3 and 5 and an average width between 2.0 to 9.0 will be meshed with one row of elements; uniform fillet strips with an average radius between 5 and 20 and an average width between 9.0 to 16.0 will be meshed with two rows of elements; and uniform fillets strips with an average radius between 20 and 30 and an avarage width between 16.0 to 24.0 will be meshed with three rows of elements. This rule does not apply to fillets with an average element width below or above the defined ranges of non-uniform fillet strips (when minimal and maximal width of fillets exceed 30%).

Figure 14.

If the width or number of rows columns in the surface fillet recognition table are empty, the next default value will be applied. In this example, that means uniform fillet strips with an average fillet width between the element sizes of 0 to 2.0 will be meshed with one row of elements.

A fillet can be meshed with enforced rows of elements, or split at its midline and meshed accordingly based on element quality.

Flange Recognition

Figure 15.

When Flange recognition is activated, geometry that represents flanges on sheet metal parts is recognized and the below options become enabled. Flanges may be modified to suppress construction lines, subdivide them into rectangular areas, or otherwise prepare them for proper meshing. As this functionality is not supported for solid geometries, it should be disabled for such models to improve performance.

Elements across flange width

Minimum number of elements to be created across the flange width.

Maximum width of flange

Maximum flange width to consider for flange recognition.

Minimum width of flange

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 and disruptions in the mesh flow.

Auto

Delete narrow flange surfaces when the maximal narrow surface width is the minimum of 0.2*element_size and min_element_size.

<value>

Delete narrow flange surfaces when the maximal narrow surface width is the minimum of the specified value.

Figure 16. Flange Narrow Surface Width	Figure 17. Narrow Surface Removed

Bead Recognition

Figure 18.

When Bead recognition is activated, geometry that represents beads on sheet metal parts is recognized and the below options become enabled.

Suppress beads with height <

Enable bead recognition and suppress any beads with a height less than the specified value. This helps eliminate small elements and aids in creating a good mesh flow.

Preserve rounded bead midline

Enforce node placement along the midline of a rounded bead.

Logo Recognition

Figure 19.

Use the Logo Recognition parameters to remove small geometric features that represent logos in the model design.

Figure 20. Logo Recognition Parameters

Remove logo with size <

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

and height <

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. As this is a heuristic tool, it 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:

$concavity\_factor=\frac{contour\_accumulated\_turn\_angle}{360}-1$

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.

Tip: Extend the recognition and removal of a logo by reducing the Concavity factor.

Thread Recognition

When Thread Recognition is activated, geometry that represents threads is recognized and the below options become enabled.

Figure 21. Thread Recognition Parameters

Remove threads with depth <

Remove cylindrical or conical threads with a depth less than the specified value, and replaces them with a smooth cylinder or cone surface.

and replacing cylinder diameter

Method used to define the diameter of the replacing cylinder or cone.

autodecide

Automatically determine diameter 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

Use diameter of the thread major.

mean

Use diameter of the thread mean.

minor

Use diameter of the thread minor.

Other Options

Figure 22.

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

Delete duplicated surfaces / with tolerance

Define which duplicate surfaces to delete before meshing.

For Delete duplicated surfaces, choose a method to find duplicate surfaces

All

Consider all of the surfaces in all of the components against each other.

Within components only

Consider all surfaces within components only. Duplicate surfaces between components are not found.

None

Do not remove duplicate surfaces.

For With tolerance, define the tolerance used when finding duplicates.

Auto

Automatically calculate the tolerance from the model size and other relevant geometric parameters.

<value>

Enter a tolerance. This is more useful when the auto tolerance is not sufficient to find all of the duplicates.

Edges equivalencing with tolerance <

Tolerance to use for equivalencing (stitching) edges, in conjunction with the options below.

auto

Calculate the tolerance internally.

<value>

Enter a tolerance. This is more useful when the auto tolerance is not sufficient to make all of the necessary connections.

Allow T-connections

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

Within components only

Allow stitching only within components. Stitching between edges of different components is not allowed.

Fix overlapped surfaces with tangency angle <

Fix overlapping surfaces.

Auto

Calculate the tangency angle internally.

<value>

Enter a maximal tangency angle to fix overlapped surfaces.

Figure 23. Overlapped Surfaces Tangency Angle	Figure 24. 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. Setting the angle to < 45 may help reduce such side effects.

Figure 25. Possible Side Effects of Fixing Overlapped Surfaces

Remove edge fillet with radius <

Square off any fillets/rounded edges located on free edges and having radii below the specified value. This helps to create a good mesh pattern in such areas. For concave fillets, this means material is removed. For convex fillets, this means material is added.

Flat feature suppression level

Suppresses feature edges based on curvature break angle. For the ease of use, you can select a curvature break angle range, which varies from very low to very high.

The curvature break angle is calculated based on Feature character size.

Choose different levels of suppression from very low to very high for more flexibility and control over capturing feature edges. very low suppression level corresponds to keeping maximum feature edges, while very high suppression level subjects the geometry to more feature edge suppression.

Figure 26. Flat feature suppression level: Very Low	Figure 27. Flat feature suppression level: Very High

If you are not satisfied with the result, choose user defined to enter a custom angle in the Custom feature angle field.

Note: The user defined and recognized features options are excluded from this suppression to enable you to capture and protect important features.

Feature character size

Calculate the curvature break angle, which is defined by an element size or calculated automatically based on characteristic dimensions of the part.

Custom feature angle

Custom feature angle.

Suppress edges by proximity <

Suppress full or partial feature edges within the defined proximity value.

This option allows geometry cleanup to consider a minimum element size defined in the criteria file, which helps to avoid minimum size quality failures. You can choose to enter an absolute value for proximity, or you can choose to use the minimum element size or its factor.

When two or more feature edges come in proximity the following guidelines or rules are used in general to determine which feature edge gets suppressed to get more consistent and predictable results:

• Full or partial feature edges within proximity are suppressed.

  
  
  Figure 28.

• Feature edges that have higher curvature values are retained.

  
  
  Figure 29.

• Boundary (free) edges are given priority.

  
  
  Figure 30.

• Base and top feature edges are given a priority while doing proximity cleanup for features like bead, bosses, and so on.

  
  
  Figure 31.

Note: The proximity value is generally kept less than the minimum element size considering node movement tolerance.

Figure 32.

Preserve boundaries between components

Do not suppress or remove components' boundary edges during geometry cleanup, and do not move elements nodes 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.

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.

Figure 33.

Batchmesher has a powerful mesh flow algorithm which considers the shape of the geometry and aligns the mesh to create orthogonal meshes automatically. It also helps to reduce number of trias and places them strategically to avoid bad mesh patterns. Batchmesher is able to control the average element size in order to generate a more uniform mesh.

When Mesh options is activated, the following options become enabled.

These parameters control the behavior of the post-mesh element cleanup operations. They are intended to fix elements failing the quality criteria, to reduce number of tria elements for mixed/quad meshes, to correct bad mesh patterns, and to fix mesh flow for fillets. All of the element cleanup operations are compliant with the quality criteria, in that they should improve or at least not worsen the mesh quality.

Figure 39.

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

Mesh selected components without geometry cleanup

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

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

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.

Click to add 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. Click to remove the selected row from the table.