Surface Edit Panel

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

Location: Geom page

Note: The topology revision option in the Meshing subpanel of the Options panel 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 affected surfaces. For instance, if you want to trim a surface with two nodes, the elements of the surfaces that are affected 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 edge function or the offset function.

Trim with Nodes Subpanel

Use the Trim with Nodes subpanel to trim (split) a surface using nodes. A surface can be trimmed with two or more nodes, or with a node normal to an edge.

For a two nodes trim, select two nodes that belong to a single surface. Engineering Solutions detects the surface that needs to be trimmed. If Engineering Solutions 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 direction normal to the surface.

For a multiple nodes trim, Engineering Solutions 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 a projection 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 edge trim, select a node and a surface edge. Engineering Solutions splits/trims the surface along a straight line which is perpendicular to the selected edge and connects the edge to the selected node.
Option Action
two nodes: node selector Select the first and second node on a single surface. The surface operation is performed after you select the second node.
multiple nodes: surfs selector Select 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 to edge: lines selector Select the line to begin the trim operation. The surface is split along a vector perpendicular to this line that passes through the selected node.

Trim with Lines Subpanel

Use the Trim with Lines subpanel to trim/split surfaces using a line (or a group of lines). There are three methods that can be used to trim a surface with lines.
Trim with a cut line
Drag or draw a line across to define the cut.
Trim lines
Sweep existing lines to surfaces, effectively projecting a copy of the selected 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
Select existing lines on a surface and create offset or scaled copies of them to trim the surface.

Trimming the 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 the entire surface/distance = toggle to set the distance the line is swept, or use a calculated distance that trims 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.

An example of trimming a surface with lines is shown in Figure 1 and Figure 2.

Figure 1. Before Trimming: Surfaces Selected

Figure 2. After Trimming: Entire Surface Trimmed with Line
An example of trimming a surface with offset lines is shown in Figure 3.

Figure 3. Outer Rectangular Surface and Circular Line Selected
Option Action
with cut line: surfs selector Select the surface to trim.
drag a cut line 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 Create a curved line that passes through the points you specify
close line Create a closed loop, automatically connecting the first and last points that you specify.
fill cuts Insert pieces of the trimmer surface into closed loops of new edges.
with line: surfs selector Select the surface to trim.
with lines: lines selector Select the type of line you want used to trim the surface on your model.
free lines (default)
Select free lines.
surf edges
Select surface edges.
Select any type of line.
along a vector / normal to surface
along a vector
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.
normal to surface
Trim the surface directly under the line, as if the line were a new surface that intersects the selected surface perpendicularly.
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 line's end points as fixed nodes on the trimmed surface.
all attached surfaces / selected surfaces
all attached surfaces
Create a new offset trim line in each surface that the selected line connects to.
selected surfaces
Specify which surfs you wish to trim.
offset Specify the offset. The resulting additional lines will be generated this distance from the selected ones.
select closed loops Automatically select enclosed chains of line segments when selecting lines.

Clear this checkbox to only select the line segments specifically clicked.

Trim with Surfs/Plane Subpanel

Use the Trim with Surfs/Plane subpanel 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 broken into smaller pieces (surfaces). After the surfaces are trimmed, you can delete any unwanted surfaces.

An example of trimming a surface with planes is shown in Figure 4 and Figure 5.

Figure 4. Surface Selected

Figure 5. Surface Trimmed
An example of trimming a surface with a surface is shown in Figure 6 and Figure 7.

Figure 6. Smaller Surface to be Trimmed

Figure 7. Surface Trimmed
Option Action
with plane: surfs selector Select the surface to trim.

When trim with planes is active, a fill cuts mode is available. This mode is turned off by default. Select fill cuts checkbox to enable it.

vector selector Select the vector coordinates.
fill cuts Insert pieces of the trimmer surface into closed loops of new edges.
with surfs: surfs selector Select the surface to trim.
trim both Enable both surfaces trim each other.
extend trimmer Extend the trimming operation beyond the boundaries of the nodes, or lines that you used to define it.
Note: Available when trim both is inactive.
self-intersecting surfs: surfs selector Select 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 single mass of surfaces and Engineering Solutions 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 Subpanel

Use the Untrim subpanel to remove trim lines so that the trimmed surfaces return to their previous, untrimmed state.
Option Action
at cursor: edge Remove a single, specific trim line.

Figure 8. . Clicking each of the circular trim lines (holes) removes the trim and extends the surface.
all trim lines of surfs: surfs selector Remove all of the trim lines on one or more surfaces that are selected.

Figure 9. . Selecting the front face surface trims all of its lines, including the one forming the hole in its center.
Selected trim lines of surfs: lines Select trim lines so that you can untrim portions of the surface.

Figure 10. Edges Selected. Arrows indicate selected edges.

Figure 11. Edges Trimmed . Each selected edge is trimmed.
Selected trim lines of surfs: shortcut/ extend Select a method for untrimming surfaces.
Generate a straight line between vertices.

Figure 12.
Follow existing geometry by extending the edges using adjacent edges as a guide.

Figure 13.
Selected trim lines of surfs: keep vertices Keep the points denoting vertices after untrimming.
internal trim lines: lines selector Remove one or more trim lines inside the boundaries of the surface selected.

Figure 14. . Clicking each shared edge line removes it, stitching the adjacent surfaces.

Offset Subpanel

Use the Offset subpanel 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, and so on) is maintained during the offset function. Some individual surfaces will be trimmed or extended to maintain 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 before the offset. You can review the normal direction of 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 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: disjointed and continuous.

Figure 15. No Offset Performed on Surface

Figure 16. Disjointed Surface

Figure 17. Offset using the Continuous Option

Figure 18. Offset using the Continuous Option, with Separator Lines Specified. Separator lines are specified at the edges of the offset surface.
Option Action
disjoint offset / continuous offset
disjoint offset
Offset moves the selected surfaces without retaining their connections to surrounding geometry.
continuous offset
Create new surfaces to connect the surface at its new position with lines that you specify, or morph any surrounding/attached surfaces to meet the offset surface if no separator lines are chosen.
update eccentricity Specify a value to be stored internally, and can be used later by the Midsurface Thickness Map utility. 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 location. Later, these values can be used in the midsurface thickness utility to map its thickness and offset to FE elements.
remove degenerations Remove degenerations, which are surfaces that become collapsed or unnecessary as a result of the offset.
autocomplete separators Automatically select all segments of a closed loop of lines when you select a single line within the segment.
surfs selector Select the surface to offset.
separator lines: lines selector Select where the offset surface should remain attached; new surfaces will be generated to keep the surface continuous.
offset = Specify a positive or negative offset value. If you are uncertain where the positive normal direction lies, use the vector normal or color normal buttons to display it, and reverse normal if 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. Surface dimensions are not preserved.

Figure 19.

Extend Subpanel

Use the Extend subpanel to extend or retract the edges of selected surfaces to meet other selected surfaces, or to close gaps between surfaces or holes within a selected surface.

Several options affect 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.
Option Action
max extension / extend over edges
max extension
Extend a surface using a maximum extension distance.
extend over edges
Extend a surface over edges to another surface.
to surfaces Extend the extending surfaces as far as necessary to meet these ones.
Note: Available when extend over edges is selected.
by distance / by thickness multiplier
by distance
Specify the maximum distance to extend surfaces.
by thickness multiplier
Specify the multiple of the surfaces' assigned thickness that yields the maximum distance to extend the surfaces.
by filling gaps / by distance / to surfaces
by distance
Specify the literal distance that selected edges will extend, measured in the same units that the model was created for.
by filling gaps
Extend the edges of the hole to fill the gap.
surfs: to extend selector Select surfaces to extend.

If you selected any shared (green) or non-manifold (yellow) edges as lines: to extend over, then this selector enables you to specify the corresponding surfaces so that Engineering Solutions knows which surface to use to determine the plane of extension for the shared/non-manifold edge.

Additionally, you may need to use this selector to specify any "target" surfaces, particularly if you use the cross extension option. 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 surfaces checkbox is enabled.

cross extension / surfs: to target selector
cross extension
Use all input surfaces as both extension and target surfaces.
This is useful when performing bulk extensions where all selected surfaces should extend to others within the selection. The input surfaces will not extend beyond the specified max extension distance, 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, all selected surface/edge combinations will be extended or shrunk. The surfaces will not cross through each other; having enabled the to surfaces checkbox ensures that they will meet rather than intersect.
surfs: to target selector
Extend the surfaces toward other surfaces.
Select the destination surfaces; the extended surfaces will then extend up to the specified distance to meet those surfaces. If the target surfaces are too far away, no extension occurs.
When using the surfs: to target selector, you can select surfaces that are already selected via the surfs: to extend selector. Selecting the same surfaces in both surfs: to extend and surfs: to target produce the same result as the cross extension option.
When selecting this option for extending a surface over an edge, the surfs: to extend that you have selected edges for via the lines: to extend over selector will extend toward the surfaces that you select with the surfs: to target selector. The target surface does not need to be selected as an extending surface.
lines: to extend over Select edges to extend. Surfaces will be extended across these lines. If you select a free edge, this also selects and highlights the corresponding surface.
surfs: to extend Select surfaces to extend.
surfs: to target / cross extension
surfs: to target
Extend the extended surfaces in the direction of the selected surfaces.
cross extension
Extend all of the selected lines and surfaces.
trim result surfaces When this checkbox is enabled and all of the selected surfaces are extended or shortened to have their edges meet, then the selected surfaces will be trimmed or stitched regardless of which components they belong to.
When this checkbox is cleared, 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 surfaces are in different components, they will not be trimmed 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).

When this checkbox is enabled 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 intersection regardless of whether or not they belong to the same component. However, when this checkbox is cleared, the surfaces are not trimmed or stitched, since they do not meet at any edges.

Shrink Subpanel

Use the Shrink subpanel to shrink the surface by drawing all of its edges (including internal edges from holes, and so on) back away from their starting location.

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 (that is further into the surface).

Figure 20. Surface Before Shrinking. The black surface has been selected.

Figure 21. Surface After Shrinking. The edges of the selected surface pull inward, away from the initial edge locations.
Option Action
surfs selector Select surfaces to shrink.
offset Specify 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.