mesh hyper

8/12/2019 Mesh Hyper

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12/28/13 Surface Edit Panel

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HyperMesh and BatchMesher

Surface Edit Panel

Location: Geompage

The Surface Editpanel allows you to perform a variety of surface editing, trimming, and creation

functions. This panel also allows you to offset surfaces in their normal direct ion.

Note: The topology revisionoption in the meshingsubpanel of

the Optionspanel affects the behavior of Surface Edit

panel. When this option is set to delete mesh, the surface

editing tools will delete the elements associated to the

affec ted surfaces. For instance, if you want to trim surface

with two nodes, the elements of the surfaces that are

affec ted by this trim are deleted and then the surface is

updated with the trim lines. This option does not have any

affect on the lines from surf edgefunction or the offsetfunction.

Subpanels and Inputs

The Surface Editpanel 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 nodestrim, you must pick two nodes that belong to a single surface. HyperMesh

automatically detec ts the surface that needs to be trimmed. (If HyperMesh detects more than

one unique surface to be trimmed, the trimming operation fails.) The surface is trimmed by a

projection of the line connecting the two nodes. The projection is performed in the direct ion

normal to the surface.

For a multiple nodestrim, HyperMesh creates a smooth line through the nodes selected (these

nodes need not be part of the surface that is selected to be trimmed) and then trims the selected

surfaces with project ion of this line along the surface normal. These trimming operations can split

the surface into multiple surfaces if the line cuts the entire surface.

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

connects the edge to the selected node.

Panel Input

Input Action

two nodes: node

selector

Pick the first and second node on a single surface. The surface operation

is performed after you select the second node.
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multiple nodes:

surfs selector

Pick the surface to trim.

multiple nodes: node

list

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

surfaces.

node normal to

edge: node selector

Select the node to begin the trim operation. The surface is split along a

vector 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 of

doing so:

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

wish 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 a

circular 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 or

scaled copies of them to trim the surface.

Trimming a selected surface(s) to a line involves sweeping a line along a vector to create a

temporary surface, and trimming the selected surface(s) with the temporary surface. You can

use theentire surface/distance =toggle to set the distance the line is swept, or use a

calculated distance that t rims the entire selected surface(s). If the temporary surface does not

intersect the selected surface(s), an error is reported. When a surface is trimmed, it is actually

broken into smaller pieces (surfaces). After the surface is trimmed, you can delete any unwanted

surfaces.

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


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Here, only the outer rectangular surfand the circular lineare selected.

Panel Input

Input Action

with cut line: surfs

selector


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 the

current location of the mouse pointer.

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

close line Creates a c losed loop, automatically connecting the first and last points

that you specify.

with line: surfs

selector


with lines: lines

selector

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

along a vector /

normal to surface

Select normal to surfaceto trim the surface directly "under" the line,

as if the line were a new surface that intersects the selected surface

perpendicularly.

Select along a vectorto specify the angle from the line to the location

of the new surface split, as if the line were a surface concurrent with

the 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 in

the 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 surfacescreates a new offset trim line in each surface

that the selected line connects to.

Selected surfacesallows you to specify which surfs you wish to trim.


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offset Specify the offset. The resulting additional lines will be generated this

distance from the selected ones.

select closed loops This checkbox will automatically select enclosed chains of line segments

when picking lines. Otherwise, only the line segments spec ifically clicked

will be selected.

Trim with Planes

Allows you to trim or split surfaces with another surface or a plane. This function determines the

intersection of the selected surfaces and a plane or a surface and then trims the original surfaces

at this intersection.

When surfaces are trimmed, they are actually broken into smaller pieces (surfaces). After the

surfaces 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 smallersurface will be trimmed.

Surface is trimmed.

Panel Input

Input Action

with plane: surfs

selector



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vector selector Select the vector coordinates.

with surfs: surfs

selector


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

self-intersecting

surfs: surfs selector

Pick the surface to trim. Every selected surface is trimmed at their

intersections with each other. This is very similar to using the trim both

option when trimming with surfs, except that you simply select a singlemass of surfaces and HyperMesh sorts them all out and trims each one

whenever it intersects any other selected surface.

This feature is useful when dealing with cases such as a grid of

intersecting surfaces. Using the intersecting surfaces trim option

allows you to separate all of the intersecting surfaces into multiple

smaller surfaces with a single action, instead of having to trim them in

pairs.

Untrim

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

state.

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.


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Selected trim lines

of surfs: lines

Use this selector to pick specific trim lines so that you can untrim portions

of 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.

extendattempts to follow existing geometry by extending the

edges using adjacent edges as a guide.


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Selected trim lines

of surfs: keep

vertices

When checked, the points denoting vertices remain even after

untrimming.

internal trim lines:

lines selector

Will remove one or more trim lines inside the boundaries of the surface

selected.

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 of

those surfaces. A negative offset value can be used to offset these surfaces in the opposite

direction of the surface normal. The topology of the surface edges (free, shared edges, etc.) is

maintained during the offset function. Some individual surfaces will be trimmed or extended to

maintain the connect ivity. 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 the

extended entity selected popup window) before the offset. You can review the normal direction

of the surfaces by c licking vector normalor color normal. If the offset direction is incorrect,the reverse normalfunction can be used to reverse the normal of a selected surface. If there

are 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: disjointedand continuous. Disjointed offsets move the

selected surfaces without retaining their connections to surrounding geometry, while continuous

ones will either morph surrounding geometry to maintain connectivity, or create new surfaces to

do so.

Examples


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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


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Input Action

disjoint offset /

continuous offset

A disjoint offsetsimply moves the surface, completely breaking its

continuity with anything that it might previously have been in contact

with.

A continuous offsetcreates new surfaces to connect the surface at

its new position with lines that you specify, or morphs any

surrounding/attached surfaces to meet the offset surface if no

separator lines are chosen.

update eccentricity This value is stored internally, and can be used later by the Midsurface

Thickness Maputility. It will not affect the movement of the offset

surface; instead, the surface's associated thickness and offset values

will remain in its original location, but be given values relative to its new

locat ion. Later, these values can be used in the midsurface thickness

utility to map its thickness and offset to FE elements.

remove

degenerations

Degenerations are surfaces that become collapsed or unnecessary as a

result of the offset.

autocomplete

separators

This option automatically selects all segments of a closed loop of lines

when you select any single line within the segment.

surfs selector Select the surface to offset.

separator lines: lines

selector

Indicate where the offset surface should remain attached; new surfaces

will be generated to keep the surface continuous.

offset = This can be a positive or negative number. If you are uncertain where

the positive normal direction lies, use the vector normalor color

normalbuttons to display it, and reverse normalif necessary/desired.

Note: The edges of a surface are offset in the normal direction, so

curved surfaces may expand or shrink when offset in either the

positive or negative direction--the surface dimensions are not

preserved.

Extend

This subpanel extends or retracts the edges of selected surfaces to meet other selected

surfaces, or to close gaps between surfaces or holes within a selected surface.


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Several optionsaffect how surfaces extension behaves, including enabling or disabling the ability

to shorten edges as well as extend them, or to force the extended edges to attempt to maintain

the 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 edgesis selected. The

extending surfaces will extend as far as necessary to meet these ones.

by distance / by

thickness multiplier

For by distance, type in the maximum distance that you wish the

surfaces 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 / by

distance / to

surfaces

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 extend

selector

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

If you selected any shared (green) or non-manifold (yellow) edges as

lines: to extend over, then this selector allows you to specify the

corresponding surfaces so that HyperWorks knows which surface to use

to 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 extensionoption

described below. Edges will only extend toward surfaces that are also

selected, even if those additional surfaces have no extending edges.

These recipient/target surfaces will also be trimmed, if the trim result

surfacescheckbox described below is active.

cross extension /

surfs: to target

selector

cross extensionallows for all input surfaces to be used as both

extension and target surfaces. This is useful for doing bulk extensions

where 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 other

surfaces within the max distance.

When selecting this option for extending a surface over an edge, then all

selected surface/edge combinations will be extended or shrunk. Despite

the name, in this case the surfaces will not cross through each other;

having selected to surfacesensures that they will meet rather than

intersect.

surfs: to targetsimply extends the surfaces toward other surfaces.

You must use this selector to pick the destination surfaces; the

extended surfaces will then extend up to the specified distance to meet
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those surfaces. If the target surfaces are too far away, no extension

occurs.

When using the surfs: to targetoption, you can select surfaces already

selected as surfs: to extend. Selecting the same surfaces in both

surfs: to extendand surfs: to targetproduces the same result as the

cross extensionoption.

When selecting this option for extending a surface over an edge, then

thesurfs: to extendthat you have selected edges for in lines: to

extend overwill extend toward the surfaces that you select with thesurfs: to targetselector. The target surface does not need to be

selected as an extending surface.

lines: to extend over Pick the edges that you wish to extend. The surfaces will be extended

across these lines. If you select a free edge, this also selects and

highlights 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 in

surfs: to target.

If cross extensionis selected, all the selected line and surfaces will be

extended.

trim result surfaces If the checkbox is on and all selected surfaces extend or shorten to

have their edges meet, then the selected surfaces will be trimmed or

stitched regardless of which components they belong to. If the

checkbox is off, the result varies further:

If the selected surfaces are in the same component, they will not

be trimmed but they will be stitched. This is the default stitching

behavior 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 for

surfaces in different components. If you need them to be

stitched, you must do so by way of edge equivalence (or some

other edge editing).

If the checkbox is on and the selected surfaces extend through their

target surfaces, or even merely to the interior without actually touching

any of the target surface edges, the surfaces will be both trimmed and

stitched at the intersect ion regardless of whether or not they belong to

the same component. However, if the checkbox is off, the surfaces are

not 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 square

would become smaller but the circular hole in its center would become larger, because the edge of

the hole draws "backward" (i.e. further into the surface).

Example:


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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 into

the surface.

Note: Holes in the surface will get larger, not smaller, as their edges

move further into the surface instead of out into the empty

space bounded by the hole.


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See Also:

HM-2030: Refining Topology to Achieve a Quality Mesh

An Alphabetical List of HyperMesh Panels

An Alphabetical List of HyperForm Panels
http://www.altairhyperworks.com/hwhelp/Altair/hw12.0/help/mfs/mfs.htm?alphabetical_list_of_hyperform_panels.htmhttp://www.altairhyperworks.com/hwhelp/Altair/hw12.0/help/hm/hypermesh_panels_listed_alphabetically.htmhttp://www.altairhyperworks.com/hwhelp/Altair/hw12.0/help/hm/hmbat.htm?hm2030.htm

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