Surface Edit Panel

HyperMesh and BatchMesher

Surface Edit Panel

Location: Geom page

The Surface Edit panel allows you to perform a variety of surface editing, trimming, and creationfunctions. This panel also allows you to offset surfaces in their normal direction.

Note: The topology revision option in the meshing subpanel ofthe Options panel affects the behavior of Surface Editpanel. When this option is set to delete mesh, the surfaceediting tools will delete the elements associated to theaffected surfaces. For instance, if you want to trim surfacewith two nodes, the elements of the surfaces that areaffected by this trim are deleted and then the surface isupdated with the trim lines. This option does not have anyaffect on the lines from surf edge function or the offsetfunction.

Subpanels and Inputs

The Surface Edit panel contains the following subpanels:

Trim with Nodes

Allows you to trim (split) a surface using nodes. The surface can be trimmed with two nodes,with multiple nodes, or with a node normal to and edge.

For a two nodes trim, you must pick two nodes that belong to a single surface. HyperMeshautomatically detects the surface that needs to be trimmed. (If HyperMesh detects more thanone unique surface to be trimmed, the trimming operation fails.) The surface is trimmed by aprojection of the line connecting the two nodes. The projection is performed in the directionnormal to the surface.

For a multiple nodes trim, HyperMesh creates a smooth line through the nodes selected (thesenodes need not be part of the surface that is selected to be trimmed) and then trims the selectedsurfaces with projection of this line along the surface normal. These trimming operations can splitthe surface into multiple surfaces if the line cuts the entire surface.

For a node normal to edge trim, you must pick a node and a surface edge. HyperMeshsplits/trims the surface along a straight line which is perpendicular to the selected edge andconnects the edge to the selected node.

Panel Input

Input Action

two nodes: nodeselector

Pick the first and second node on a single surface. The surface operationis performed after you select the second node.

multiple nodes: surfs selector

Pick the surface to trim.

multiple nodes: nodelist

Select the nodes that define the line you want to use to trim thesurfaces.

node normal toedge: node selector

Select the node to begin the trim operation. The surface is split along avector that passes through this node perpendicular to the selected line.

node normal toedge: lines selector

Select the line to begin the trim operation.The surface is split along avector perpendicular to this line that passes through the selected node.

Trim with Lines

Allows you to trim/split surfaces using a line (or a group of lines). There are three methods ofdoing so:

Trim with a cut line: you can drag or draw a line across the screen to define where youwish the cut to be made.

Trim lines: lets you sweep existing lines to surfaces, effectively projecting a copy of theselected line to the selected surface and trimming it. For example, this allows you to use acircular line currently offset from the surface to create circular holes in the surface.

With offset line: This lets you select existing lines on a surface and create offset orscaled copies of them to trim the surface.

Trimming a selected surface(s) to a line involves sweeping a line along a vector to create atemporary surface, and trimming the selected surface(s) with the temporary surface. You canuse the entire surface/distance = toggle to set the distance the line is swept, or use acalculated distance that trims the entire selected surface(s). If the temporary surface does notintersect the selected surface(s), an error is reported. When a surface is trimmed, it is actuallybroken into smaller pieces (surfaces). After the surface is trimmed, you can delete any unwantedsurfaces.

Example: Trimming a Surface with Lines

Before trimming. Surfaces are

selected.Entire surface is trimmed with the line.

Example: Trimming a Surface with Offset Lines

Here, only the outer rectangular surf and the circular line are selected.

Panel Input

Input Action

with cut line: surfsselector


drag a cut line Click this button to graphically create a dragged line to cut the surface.A line stretches dynamically between the first point selected, and thecurrent location of the mouse pointer.

smooth line Creates a curved line that passes through the points you specify

close line Creates a closed loop, automatically connecting the first and last pointsthat you specify.

with line: surfsselector


with lines: linesselector

Pick the line you want used to trim the surface on your model.

along a vector /normal to surface

Select normal to surface to trim the surface directly "under" the line,as if the line were a new surface that intersects the selected surfaceperpendicularly.

Select along a vector to specify the angle from the line to the locationof the new surface split, as if the line were a surface concurrent withthe specified vector.

entire surface /distance

Choose between trimming the entire surface, or trimming only a user-specified distance. If you choose to use a specific distance, specify it inthe distance = field.

vector selector Select the vector coordinates.

keep line endpoints Retain the lines end points as fixed nodes on the trimmed surface

all attached surfaces/ selected surfaces

All attached surfaces creates a new offset trim line in each surfacethat the selected line connects to.

Selected surfaces allows you to specify which surfs you wish to trim.

offset Specify the offset. The resulting additional lines will be generated thisdistance from the selected ones.

select closed loops This checkbox will automatically select enclosed chains of line segmentswhen picking lines. Otherwise, only the line segments specifically clickedwill be selected.

Trim with Planes

Allows you to trim or split surfaces with another surface or a plane. This function determines theintersection of the selected surfaces and a plane or a surface and then trims the original surfacesat this intersection.

When surfaces are trimmed, they are actually broken into smaller pieces (surfaces). After thesurfaces are trimmed, you can delete any unwanted surfaces.

Example: Trim with Planes

Surfaces are selected Surface is trimmed.

Example: Trim with Surface

In this example, the smaller

surface will be trimmed.

Surface is trimmed.

Panel Input

Input Action

with plane: surfsselector


vector selector Select the vector coordinates.

with surfs: surfsselector


trim both Activate this check to have both surfaces trim each other.

self-intersectingsurfs: surfs selector

Pick the surface to trim. Every selected surface is trimmed at theirintersections with each other. This is very similar to using the trim bothoption when trimming with surfs, except that you simply select a singlemass of surfaces and HyperMesh sorts them all out and trims each onewhenever it intersects any other selected surface.

This feature is useful when dealing with cases such as a grid ofintersecting surfaces. Using the intersecting surfaces trim optionallows you to separate all of the intersecting surfaces into multiplesmaller surfaces with a single action, instead of having to trim them inpairs.

Untrim

Allows you to remove trim lines so that the trimmed surfaces return to their previous, untrimmedstate.

Panel Input

Input Action

at cursor: edge Will remove a single, specific trim line.

Here, clicking each of the circular trim lines (holes) removes the trim and extends the

surface.

all trim lines ofsurfs: surfs selector

Will remove all of the trim lines on one or more surfaces that are selected.

Here, picking the front face surface trims all of its lines, including the one forming the

hole in its center.

Selected trim linesof surfs: lines

Use this selector to pick specific trim lines so that you can untrim portionsof the surface.

The arrows indicate edges picked.

Each selected edge us untrimmed

Selected trim linesof surfs: shortcut/extend

This determines how the surfaces are untrimmed.

shortcut generates a straight line between vertices.

extend attempts to follow existing geometry by extending theedges using adjacent edges as a guide.

Selected trim linesof surfs: keepvertices

When checked, the points denoting vertices remain even afteruntrimming.

internal trim lines:lines selector

Will remove one or more trim lines inside the boundaries of the surfaceselected.

Here, clicking each shared edge line removes it, stitching the adjacent surfaces.

Offset

This subpanel can be used to offset a group of surfaces by a given distance along the normals ofthose surfaces. A negative offset value can be used to offset these surfaces in the oppositedirection of the surface normal. The topology of the surface edges (free, shared edges, etc.) ismaintained during the offset function. Some individual surfaces will be trimmed or extended tomaintain the connectivity. This function moves the selected surfaces to the new location.

If you want to save the original surfaces, the selected surfaces can be duplicated (using theextended entity selected popup window) before the offset. You can review the normal directionof the surfaces by clicking vector normal or color normal. If the offset direction is incorrect,the reverse normal function can be used to reverse the normal of a selected surface. If thereare elements associated to the offset surfaces, the element will not move along with surfaces. The association between the elements and their surfaces is broken.

There are two major types of offset: disjointed and continuous. Disjointed offsets move theselected surfaces without retaining their connections to surrounding geometry, while continuousones will either morph surrounding geometry to maintain connectivity, or create new surfaces todo so.

Examples

This surface has not yet been offset.

This is a disjointed offset.

This offset uses the "continuous" option.

This offset uses the "continuous" option, with separator lines specified at the edges of the offset surface.

Panel Input

Input Action

disjoint offset /continuous offset

A disjoint offset simply moves the surface, completely breaking itscontinuity with anything that it might previously have been in contactwith.

A continuous offset creates new surfaces to connect the surface atits new position with lines that you specify, or morphs anysurrounding/attached surfaces to meet the offset surface if noseparator lines are chosen.

update eccentricity This value is stored internally, and can be used later by the MidsurfaceThickness Map utility. It will not affect the movement of the offsetsurface; instead, the surface's associated thickness and offset valueswill remain in its original location, but be given values relative to its newlocation. Later, these values can be used in the midsurface thicknessutility to map its thickness and offset to FE elements.

removedegenerations

Degenerations are surfaces that become collapsed or unnecessary as aresult of the offset.

autocompleteseparators

This option automatically selects all segments of a closed loop of lineswhen you select any single line within the segment.

surfs selector Select the surface to offset.

separator lines: linesselector

Indicate where the offset surface should remain attached; new surfaceswill be generated to keep the surface continuous.

offset = This can be a positive or negative number. If you are uncertain wherethe positive normal direction lies, use the vector normal or colornormal buttons to display it, and reverse normal if necessary/desired.

Note: The edges of a surface are offset in the normal direction, socurved surfaces may expand or shrink when offset in either thepositive or negative direction--the surface dimensions are notpreserved.

Extend

This subpanel extends or retracts the edges of selected surfaces to meet other selectedsurfaces, or to close gaps between surfaces or holes within a selected surface.

Several options affect how surfaces extension behaves, including enabling or disabling the abilityto shorten edges as well as extend them, or to force the extended edges to attempt to maintainthe overall shape of the surface.

Panel Input

Input Action

max extension /extend over edges

Max extension: extend the surface using a maximum extensiondistance.

Extend over edges: extend a surface over edges to another surface

to surfaces This choice is available when Extend over edges is selected. Theextending surfaces will extend as far as necessary to meet these ones.

by distance / bythickness multiplier

For by distance, type in the maximum distance that you wish thesurfaces to extend.

For by thickness multiplier, type in the multiple of the surfaces'assigned thickness that yields the maximum distance you wish thesurfaces to extend.

by filling gaps / bydistance / tosurfaces

by distance: This is the literal distance that selected edges will extend,measured in the same units that the model was created for.

by filling gaps: extends the edges of the hole to fill the gap.

surfs: to extendselector

Use this selector to pick only the surfaces that you wish to extend.

If you selected any shared (green) or non-manifold (yellow) edges aslines: to extend over, then this selector allows you to specify thecorresponding surfaces so that HyperWorks knows which surface to useto determine the plane of extension for the shared/non-manifold edge.

Additionally, you may need to use use this selector to specify any"target" surfaces, particularly if you use the cross extension optiondescribed below. Edges will only extend toward surfaces that are alsoselected, even if those additional surfaces have no extending edges. These recipient/target surfaces will also be trimmed, if the trim resultsurfaces checkbox described below is active.

cross extension /surfs: to targetselector

cross extension allows for all input surfaces to be used as bothextension and target surfaces. This is useful for doing bulk extensionswhere all selected surfaces should extend to others within the selection.The input surfaces will not extend beyond the specified max extensiondistance, nor will any of their edges extend if there are no othersurfaces within the max distance.

When selecting this option for extending a surface over an edge, then allselected surface/edge combinations will be extended or shrunk. Despitethe name, in this case the surfaces will not cross through each other;having selected to surfaces ensures that they will meet rather thanintersect.

surfs: to target simply extends the surfaces toward other surfaces. You must use this selector to pick the destination surfaces; theextended surfaces will then extend up to the specified distance to meet

those surfaces. If the target surfaces are too far away, no extensionoccurs.

When using the surfs: to target option, you can select surfaces alreadyselected as surfs: to extend. Selecting the same surfaces in bothsurfs: to extend and surfs: to target produces the same result as thecross extension option.

When selecting this option for extending a surface over an edge, thenthe surfs: to extend that you have selected edges for in lines: toextend over will extend toward the surfaces that you select with thesurfs: to target selector. The target surface does not need to beselected as an extending surface.

lines: to extend over Pick the edges that you wish to extend. The surfaces will be extendedacross these lines. If you select a free edge, this also selects andhighlights the corresponding surface.

surfs: to extend Pick the surfaces that you wish to extend.

surfs: to target /cross extension

Extended surfaces will extend in the direction of surfaces selected insurfs: to target.

If cross extension is selected, all the selected line and surfaces will beextended.

trim result surfaces If the checkbox is on and all selected surfaces extend or shorten tohave their edges meet, then the selected surfaces will be trimmed orstitched regardless of which components they belong to. If thecheckbox is off, the result varies further:

If the selected surfaces are in the same component, they will notbe trimmed but they will be stitched. This is the default stitchingbehavior for surfaces in the same component.

If the selected surfs are in different components, they will not betrimmed or stitched. This is the default stitching behavior forsurfaces in different components. If you need them to bestitched, you must do so by way of edge equivalence (or someother edge editing).

If the checkbox is on and the selected surfaces extend through theirtarget surfaces, or even merely to the interior without actually touchingany of the target surface edges, the surfaces will be both trimmed andstitched at the intersection regardless of whether or not they belong tothe same component. However, if the checkbox is off, the surfaces arenot trimmed or stitched, since they do not meet at any edges.

Shrink

Shrinks the surface by drawing all of its edges (including internal edges from holes, etc.) "back"away from their starting location.

For example: if you shrink a square surface that has a circular hole in the center, the squarewould become smaller but the circular hole in its center would become larger, because the edge ofthe hole draws "backward" (i.e. further into the surface).

Example:

The black surface has been selected.

The edges of the selected surface pull inward, away from the initial edge locations.

Panel Input

Input Action

surfs selector Select the surfs to shrink.

offset This is the distance that each edge of the surface moves further intothe surface.

Note: Holes in the surface will get larger, not smaller, as their edgesmove further into the surface instead of out into the emptyspace bounded by the hole.

See Also:

HM-2030: Refining Topology to Achieve a Quality Mesh

An Alphabetical List of HyperMesh Panels

An Alphabetical List of HyperForm Panels

Documents

Surface Edit Panel