Engineering Solutions

Defeature panel

Defeature panel

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Defeature panel

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Use the Defeature panel to find and delete pinholes, fillets on surfaces and surface edges, and duplicate surfaces.

 

Panel Usage

Each of the subpanels allows you to manually select the feature that you wish to delete, but also supports a three-step process that can locate such features for you:

Step

Action

Step 1: Detection

Select surfaces to search for pinholes, fillets, or duplicates; set detection parameters; find all features matching the criteria.

Step 2: Select / Deselect

Fine-tune the selection to include only the features you wish to delete/remove from the model.

Step 3: Removal

Removal of the selected features

 

Subpanels and Inputs

The Defeature panel contains the following subpanels and command buttons:

expand-green-10Pinholes

Use the Pinholes subpanel to identify and close pinholes (circular internal loops lying on a relatively planar surface). You can search for pinholes as well as elongated non-circular slots based on diameter.  Pinholes with a diameter equal to or less than the value you specify will be located and can be removed/closed. Similarly, slots whose lengths are less than the diameter you specify will also be found and can be closed.

A pinhole is any internal loop that can be matched to a circular shape under two conditions:

•It lies on a surface that is almost planar.
•The ratio between the area and the perimeter of the shape is above a reasonable threshold, defined thusly: For a given length of the loop, the circle shape yields maximal area. Engineering Solutions checks that the area of the loop is at least half of the expected area of a perfect circle with the same characteristic diameter.

 

Engineering Solutions uses a ratio between the circumference and the area to determine if it is a pinhole.  It marks as a pinhole those internal loops that are equivalent or smaller than the given diameter.

pinhole_example

The holes on the top of this part are pinholes.

Panel Inputs

Option

Action

surfs selector

Select the surface(s) on which to locate pinholes

pinholes

Select the pinholes.

diameter <

Enter a value greater than the maximum allowable pinhole diameter.

Decimal values are acceptable.  This value must be greater than the maximum acceptable diameter because it is not inclusive; Engineering Solutions locates any holes that are smaller than (but not equal to) the specified diameter, plus the node tolerance value specified on the options page.  Holes do not have to be perfectly round--the diameter is treated as a characteristic dimension.  See Comments below.

 
expand-green-10Surf Fillets

Use the Surf Fillets subpanel to identify and remove surface fillets (curved surfaces that create a smooth transition between relatively perpendicular geometric entities). You can identify fillets based on radius, because fillets are always uniform arcs. You can also select a fillet by picking one of the edges that it connects. Once found, fillets can be removed using tools that display automatically after the find process.

surface_fillets_example

In this image, the curved yellow surfaces are fillets.

When removing surface fillets, keep the following in mind: The algorithm starts after you select the surfaces and click remove.  Selected surfaces are considered to be fillet surfaces. The work of the removal algorithm does not depend on the result of the work by the fillet detection algorithm (which is invoked by pressing the find fillets button). You can manually select all those surfaces that you believe to be fillets and want removed. Once such a decision has been made and the surfaces are selected, the removal algorithm does not interfere with this decision in any way other than simply failing to defillet wrongfully (in its opinion) selected surfaces.

The algorithm operates in the following manner.  All surfaces adjacent to the fillet (selected) surfaces, and connected to them by green edges, are extended and intersected with each other.  Surface extensions are trimmed by intersections with other surfaces.  If trimmed extended surfaces and original fillet surfaces can form a closed body, then "defilleting" is possible and is made by replacing the set of fillet surfaces with the set of extended surfaces trimmed by mutual intersections.  The algorithm fails if modification of the body would require modification of some of the original surfaces adjacent to the fillet surfaces.  It also fails if extended surfaces trimmed by other surfaces become degenerate or if the intersection of extended surfaces requires an unreasonably large extension distance (several times the characteristic size of the fillet).  This means, for example, that the algorithm might legally (not as a result of a bug) fail if in the chain of several almost collinear fillets, you select only one of them. The reason for this is that if neighboring fillets are not treated as fillets, their extension is almost parallel to the selected fillet surface.  This may result in either a degenerate modification volume or such an extension would cut through existing surfaces and modifying the body would require retrimming of existing surfaces.  Another example of a non-feasible situation is when the fillet surface connects to almost parallel surfaces.  This situation would require intersection of those surface extensions at a distance far exceeding the characteristic fillet size.

 

Panel Inputs

Option

Action

lines selector

Select lines as the fillet search algorithm.

surfs

Select surfs as the fillet search algorithm.

It is also possible to select fillet surfaces manually, without using automatic detection algorithms. To do this, click find fillets immediately after entering the subpanel, without selecting any lines or surfaces.

min radius

Minimum fillet radius allowed.

max radius

Maximum fillet radius allowed.

 
expand-green-10Edge Fillets

Use the Edge Fillets subpanel to identify and remove edge fillets. Similar to surface fillets, edge fillets create smooth curves at the intersection of relatively perpendicular free edges.  You can identify them based on the radius of the fillet arc, and then remove them.

An edge fillet is a part of the trimming loop of a surface that can be roughly equivalenced to a circular arc under the conditions that are specified in the min and max radius and angle fields.

Current implementation does not detect or process fillets that belong to different surfaces or span across different suppressed surfaces.

edge_fillets_example_defeaeture

In this image, the arrows point to edge fillets

Panel Inputs

Option

Action

surfs

Select surfs as the fillet search algorithm.

It is also possible to select fillet surfaces manually, without using automatic detection algorithms. To do this, click find fillets immediately after entering the subpanel, without selecting any lines or surfaces.

fillets

Select the fillets.

min radius

Minimum fillet radius allowed.

max radius

Maximum fillet radius allowed.

min angle

Minimum angle allowed at the interior angle formed by the intersection of the tangents to the edges calculated at the start and end of the fillet.

all / fillets / rounds

If you use the default setting, all, then all of the detected fillets are highlighted.  You can change the setting to fillets or rounds to select only concave regions (fillets) or convex regions (rounds).  After the fillets are detected, you can change the detection parameters. Fillets/rounds that do not meet new criteria are then deselected.  However, detection of additional fillets that meet a lesser criterion is not performed unless you click find again.

trim - intersect node

Use these selectors to manually remove an edge fillet. After selecting the first and last node, the fillet is processed immediately by calculating tangents at the beginning and at the end.  The tangents are intersected and this sharp corner replaces the original geometry between start/end almost regardless of what is inside the region.

 
expand-green-10Duplicates

Use the Duplicates subpanel to find duplicate surfaces and remove them. Engineering Solutions determines which faces are duplicates and which faces are correct based on multiple criteria. All other things being equal, it will try to select all duplicates except for the one with the lowest surface ID.  However, if deleting such surfaces would break continuity with adjacent (non-duplicate) surfaces, it checks for a surface that maintains continuity and retains that one (regardless of its ID) while selecting the other duplicates.

 

Panel Inputs

Option

Action

surfs / faces selector

Choose to search for either duplicate surfaces or duplicate faces.

cleanup tol =

This determines how much of a gap can exist between two otherwise identical surfaces before they are considered to be intentionally separate surfaces rather than duplicates.  If the gap between such surfaces is this value or less, they are assumed to be duplicates.

 
expand-green-10Symmetry

Use the Symmetry subpanel to find symmetrical surfaces or compare selected surface sets for symmetry.  You can reorganize found symmetric surfaces into separate components or delete one subset of a pair of symmetric surface sets.

This can be helpful with highly symmetrical components, because you can then perform geometry cleanup on only one half, mesh it, and then mirror the mesh instead of having to clean up the entire component prior to meshing.

 

Panel Inputs

Option

Action

find symmetry / compare

Find symmetry locates surfaces within a single component that are mirror images of one another across a plane of symmetry that you specify.

Compare finds symmetric surfaces among different components that you select

surfs selector

Select the surface.

vector selector

Defines your axis of symmetry.  The base node B indicates its location while the other options (such as axes or N1/N2/N3) determine its orientation.

reorganize

Places the symmetric surfaces into new, separate componentm

delete positive

Used when finding symmetry. Deletes the symmetric surfaces on the positive side of the symmetry axis.

delete negative

Used when finding symmetry. Deletes the symmetric surfaces on the negative side of the symmetry axis.

delete first

Used when comparing symmetry. Deletes the symmetric surfaces from the first set of selected surfaces.

delete second

Used when comparing symmetry. Deletes the symmetric surfaces from the second set of selected surfaces.

 
expand-green-10Command Buttons

The following action buttons appear throughout the subpanels:

Button

Action

find

Find the selection.

delete

Delete the selection.

reject

Reject the selection

remove

Remove all selected (highlighted) fillets.

return

Exit the panel.