# Surfaces Panel

Use the Surfaces panel to create surfaces using a wide variety of methods.

Location: Geom page

## Square Subpanel

Use the Square subpanel to create 2D square surface primitives.
Option Action
plane and vector selector Define the plane in which the square surface lies, including the base node located at the square center. If a vector is specified, it defines the surface normal.
Note: Because you are required to select nodes, suitable nodes must already exist in your model or a mesh from which you can select nodes. The Square subpanel does not contain any tools to create new nodes.
size Specify the size, indicating both the total length and width. Remember that these dimensions will be centered on the base node, therefore the resulting square will extend half this value away from it in each direction.

## Cylinder Full Subpanel

Use the Cylinder Full subpanel to create 3D full cylinder surface primitives.
Option Action
bottom center Select the node that defines the center of the bottom cylinder face.
normal vector Select the vector between the bottom center node and the normal vector node that is the cylinder axis, thereby defining the cylinder orientation. This does not indicate the actual cylinder height.
Base radius Specify the radius for the top and bottom cylinder faces.
height Specify the cylinder height.

## Cylinder Partial Subpanel

Use the Cylinder Partial subpanel to create 3D partial cylinder surface primitives.
Option Action
bottom center Select the node that defines the center of the bottom cylinder face.
normal vector Select the vector between the bottom center node and the normal vector node that defines the cylinder axis, thereby indicating the cylinder orientation. This does not indicate the actual cylinder height.
major vector Select the vector between the bottom center node and the major vector node that determines the zero-degree point of an arc defining the curved surface of the partial cylinder. This arc extends in a direction based on the normal vector using the right-hand rule, with its start angle and end angle specified relative to this vector.
Base radius Specify the radius of the top and bottom cylinder faces.
Height Specify the cylinder height.
Start angle Specify the starting arc angle, measured from the major vector node in a direction based on the normal vector using the right-hand rule.
End angle Specify the ending arc angle, measured from the major vector node in a direction based on the normal vector using the right-hand rule.

The difference between this and the start angle determines the arc of the partial cylinder, and therefore the arc of the cutout in the partial cylinder.

For example, if your start angle is 15 degrees, and your end angle is 285 degrees, the resulting cylinder has a base with a 270 degree arc and a 90 degree cut.

Axis ratio Specify a percentage of the major vector. This value must be greater than zero and less than or equal to 1. Decimal values create oval-shaped cylinders instead of circular ones.

## Cone Full Subpanel

Use the Cone Full subpanel to create 3D full cone surface primitives.
Option Action
bottom center Select the node that defines the center of the bottom cone face.
normal vector Select the vector between the bottom center node and the normal vector node defines the cone axis, thereby indicating the cone orientation. This does not indicate the actual cone height.
Top radius Specify the top radius of the top cone face. If set to 0, a cone tip is created; if greater than zero, the cone has a flat top.
Base radius Specify the base radius of the bottom cone face. This value must be greater than 0.
Height Specify the cone height.

## Cone Partial Subpanel

Use the Cone Partial subpanel to create 3D partial cone surface primitives.
Option Action
bottom center Select the node that defines the center of the bottom cone face.
normal vector Select the vector between the bottom center node and the normal vector node that defines the cone axis, thereby indicating the cone orientation. This does not indicate the actual cone height.
major vector Select the vector between the bottom center node and the major vector node that determines the zero-degree point of an arc defining the curved surface of the partial cone. This arc extends in a direction based on the normal vector using the right-hand rule, with its start angle and end angle specified relative to this vector.
Top radius Specify the radius of the top cone face. If set to 0, a cone tip is created; if greater than zero, the cone has a flat top.
Base radius Specify the radius of the bottom cone face. Must be greater than 0.
Height Specify the distance between the cone's base and its top.
Start angle Specify the starting arc angle, measured from the major vector node in a direction based on the normal vector using the right-hand rule.
End angle Specify the ending arc angle, measured from the major vector node in a direction based on the normal vector using the right-hand rule. The difference between this and the start angle determines the arc of the partial cone, and therefore the arc of the cutout in the partial cone. For example, if your start angle is 15 degrees, and your end angle is 285 degrees, the resulting cone has a base with a 270 degree arc and a 90 degree cut.
Axis ratio Specify the percentage of the major vector. This value must be greater than zero and less than or equal to 1. Decimal values create oval-shaped cones instead of circular ones.

## Sphere Center and Radius Subpanel

Use the Sphere Center and Radius subpanel to create 3D sphere surface primitives by specifying the center and radius.
Option Action
center Select the node that defines the center of the sphere.
Radius Define the sphere radius. A value can be specified, or a node that defines the radius (measured from the center node) can be selected.

## Sphere Four Nodes Subpanel

Use the Sphere Four Nodes subpanel to create 3D sphere surface primitives by specifying four nodes.
Option Action
node list Select nodes. The selected nodes cannot all be coplanar. The smallest sphere that passes through all four nodes is created. If more than four nodes are selected, only the four most recent are used.

## Sphere Partial Subpanel

Use the Sphere Partial subpanel to create 3D partial sphere surface primitives.
Option Action
center Select the node that defines the center of the sphere.
R node Select the vector between the center node and R node that defines the first axis of the sphere.
phi/theta Select the node (phi or theta) that defines the second axis and complete the definition of the sphere's orientation.
phi
The phi zero degree angle starts on the vector between the center node and R node, and rotates in the plane created by the center node, R node, and phi nodes. This plane also therefore defines the axis for theta, which starts its zero degree angle on the vector extending from the center node normal to the plane defined by the center node, R node, and phi nodes.
theta
The theta zero degree angle starts on the vector between the center node and R node, and rotates in the plane created by the center node, R node, and theta nodes. This plane also therefore defines the axis for phi, which starts its zero degree angle on the vector extending from the center node normal to the plane defined by the center node, R node, and theta nodes.
Theta begin Specify the starting angle for theta. Valid values for theta are from 0.0 to 360.0.
Theta end Specify the ending angle for theta.
Phi begin Specify the starting angle for phi. Valid values for phi are from 0.0 to 90.0.
Phi end Specify the ending angle for phi.

## Torus Center and Radius Subpanel

Use the Torus Center and Radius subpanel to create 3D torus surface primitives by specifying the center, normal direction, minor radius and major radius.
Option Action
center Select the node that defines the center of the torus.
normal vector Select the vector between the center node and the normal vector node that is the torus axis, thereby defining the torus orientation.
Major radius Specify the outside radius of the torus, measured from the center node.
Minor radius Specify the radius of the circular cross-section of the torus.

## Torus Three Nodes Subpanel

Use the Torus Three Nodes subpanel to create 3D torus surface primitives by specifying three nodes. The three nodes must define a plane and cannot be collinear. The torus is created perpendicular to the plane, but edge-on relative to the vector between the major center and minor center nodes.
Option Action
major center Select the node that defines the absolute center of the torus.
minor center Select the node that defines the center of the circular cross-section of the torus.
minor radius Distance between the minor center node and the minor radius node defines the radius of the circular cross-section of the torus.

## Torus Partial Subpanel

Use the Torus Partial subpanel to create 3D partial torus surface primitives.
Option Action
center Select the node that defines the absolute center of the torus.
normal Select the vector between the center node and the normal node that defines the torus axis.
major axis Select the vector from the center node to the major axis node which completes the definition of the torus plane. Combined with the normal node, this provides the complete torus orientation.
Major radius Specify the outside radius of the torus, measured from the center node.
Major start angle Specify the starting arc angle for the major circumference (ring), measured from the torus plane in a direction based on the torus axis using the right-hand rule.
Major end angle Specify the ending arc angle for the major circumference (ring), measured from the torus plane in a direction based on the torus axis using the right-hand rule. The difference between this and the major start angle determines the major arc of the torus, and therefore the arc of the major cutout in the partial torus. For example, if your major start angle is 15 degrees, and your major end angle is 285 degrees, the resulting torus is an open ring with a 270 degree arc and a 90 degree cut.
Minor radius Specify the radius of the circular cross-section of the torus.
Minor start angle Specify the starting arc angle for the minor circumference (cross-section), measured from the mid-plane of the cross-section in a direction based on the cross-section centerline using the right-hand rule.
Minor end angle Specify the ending arc angle for the minor circumference (cross-section), measured from the mid-plane of the cross-section in a direction based on the cross-section centerline using the right-hand rule. The difference between this and the minor start angle determines the minor arc of the torus, and therefore the arc of the minor cutout in the partial torus. For example, if your minor start angle is 15 degrees, and your minor end angle is 285 degrees, the resulting torus has a cross-section with a 270 degree arc and a 90 degree cut.

## Spin Subpanel

Use the Spin subpanel to create surfaces by spinning lines or a node list around an axis.
Option Action
lines/node list selector Select the lines or node list to spin.

If a node list is specified, a line will first be fit through the specified nodes.

plane and vector selector Select the plane/vector that defines the rotation axis.

If a vector is defined or selected, this represents the axis of rotation. If a plane is defined, the plane normal represents the axis of rotation.

The base node of the plane/vector represents the center of rotation.

Merge input lines Merge the input lines into smooth lines when possible, and create a surface for each group that forms a tangentially continuous line.

Clear this checkbox to create a surface for each input line, with shared edges connecting surfaces where relevant.

Note: Available when the entity selector is set to lines.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components become a part of the same surface.
Note: Available when the entity selector is set to lines.
Start angle Specify the start angle that defines the initial angle before the lines/nodes are spun. The angle is measured about the axis of rotation using the right-hand rule.
End angle Specify the end angle that defines the final angle through which the lines/nodes are spun. The angle is measured about the axis of rotation using the right-hand rule. The total angle is given by (end angle - start angle).
spin+ / spin- Define the direction of the spin.
spin+
Defined using the right-hand rule around the axis of rotation and uses the start angle and end angle values as specified.
spin-
Defined in the opposite direction and uses the negative of the specified start angle and end angle values.

## Drag Along Vector Subpanel

Use the Drag Along Vector subpanel to create surfaces by dragging lines or a node list along a vector.
Option Action
lines/node list selector Select the lines or node list to drag.

If a node list is specified, a line will first be fit through the specified nodes.

plane and vector selector Select the plane/vector defining the drag direction. If a vector is defined or selected, this represents the positive drag direction. If a plane is defined, the plane normal represents the positive drag direction.
Merge input lines Merge the input lines into smooth lines when possible, and create a surface for each group that forms a tangentially continuous line.
Clear this checkbox to create a surface for each input line, with shared edges connecting surfaces where relevant.
Note: Available when the entity selector is set to lines.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components become a part of the same surface.
Note: Available when the entity selector is set to lines.
Distance Specify the length to drag the lines/nodes along the vector.
spin+ / spin- Define the direction of the drag.
spin+
Defined using specified vector direction.
spin-
Defined in the opposite direction.

## Drag Along Line Subpanel

Use the Drag Along Line subpanel to create surfaces by dragging lines or a node list along another line, called the "drag line".
The reference node and transformation plane options require the following definitions:
S
Start of drag line (path), which is the closest end of the drag line to the vertices of the line to be dragged. Drag + follows this direction. Drag - follows the opposite direction.
T
Tangent of the drag line at S.
R
Reference node.
B
Base node of the transformation plane.
N
Normal vector of the transformation plane.
Option Action
lines / node list Select the lines or node list to drag.
If a node list is specified, a line will first be fit through the specified nodes and then dragged.
line list Select the lines that the drag will follow. This can also be a series of connected lines.
Merge input lines Merge the input lines into smooth lines when possible, and create a surface for each group that forms a tangentially continuous line.

Clear this checkbox to create a surface for each input line, with shared edges connecting surfaces where relevant.

Note: Available when the entity selector is set to lines.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components become a part of the same surface.
Note: Available when the entity selector is set to lines.
Frame mode Choose a method for how lines are translated and rotated during the drag. In some cases, the differences are only apparent when performing relatively complex drags.
fixed frame
the lines are only translated during the drag, not rotated.
line tangent
in addition to the translation of the fixed frame option, the lines are also rotated in the same way that the tangent of the line list rotates.
frenet frame
in addition to the translation and rotation of the line tangent option, the lines also rotate around the line list tangent axis in the same way as the curvature vector rotates.
The Frenet frame option does not work well when the curvature of the line list is not smooth or includes large jumps.
Reference node Select the node used to translate the drag (path) line prior to the drag, thus producing results as if the drag line actually began at the selected reference node. By default, R=S. If a different S is specified, the line list is translated by the vector defined from S to R.
Transformation Select the plane used to translate and rotate the input lines prior to the drag. By default, no transformation occurs (B=R and N=T). If specified, the lines are translated by the vector defined from R to B, and are rotated from N to T.
drag+ / drag- Define the direction of the drag.
drag+
Defined at the start of the drag line, which is the closest end of the line to the line vertices.
drag-
Defined in the opposite direction.

## Drag Along Normal Subpanel

Use the Drag Along Normal subpanel to create surfaces by dragging lines along their normal.
Note: Not all lines have a defined normal, but curved lines do.
Option Action
line list Select the line list to drag.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components become a part of the same surface.
Note: Available when the entity selector is set to lines.
Distance Choose a method for defining the length to drag the line along its normal.
uniform
Drag the line list a uniform distance.
variable
Drag the line list linearly based on a start and end drag value.
Link type Choose a method used to determine how the surface is generated when there is a discontinuity (other than 180 degrees) in the direction of the curvature of the input line list.
interpolate
Interpolate the drag direction on both sides of the discontinuity to allow a smooth transition. In this case, along the interpolation region, the drag direction is going to be different than the curvature direction. Amplified fluctuations, which would occur in the drag because of small ripples in the input curve, are smoothed out with this option.
Do no insert a link if there is a jump in offset direction at points where input lines meet. In this case, the offset lines may become disconnected.
 Figure 28. Interpolate Figure 29. No Link
Switch start point By default, the start of the line is indicated by the end of the chain that has the arrow after selecting the lines. Enable this checkbox to reverse the start point.
drag+ / drag- Define the direction of the drag.
drag+
Based on the curvature of the selected lines, and is shown by an arrow at the start of the line list.
drag-
Defined in the opposite direction.

## Drag Along Normal from Surface Subpanel

Use the Drag Along Normal from Surface subpanel to create surfaces by dragging lines along the normal of their adjacent surfaces.
Option Action
lines Select the lines to drag.
Note: Only surface edges may be selected.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components become a part of the same surface.
Note: Available when the entity selector is set to lines.
Distance Specify the length to drag the line along its adjacent surface normal. Both positive and negative values are accepted. A negative value indicates to use the direction opposite the normal directions.
drag+ / drag- Define the length to drag the line along its adjacent surface normal. Both positive and negative values are accepted. A negative value indicates to use the direction opposite the normal directions.
drag+
Defined as the normal directions. A negative distance value reverses this direction.
drag-
Defined as the opposite of the normal directions. A negative distance value reverses this direction.

## Ruled Subpanel

Use the Ruled subpanel to create surfaces by interpolating linearly between lines or nodes.
Option Action
line list / node list Use the first selector to define the first edge of the surface to create. Use the second selector to define the second edge of the surface to create.

If a node list is selected, a line will first be fit through the specified nodes.

auto reverse Prevent "bow tie" surfaces from being generated. The lines used to create the surface can be ordered in different directions. This results in a surface that crosses itself resembling a bow tie. Enabling this option ensures that surfaces are generated with a similar order on each side.

## Spline/Filler Subpanel

Use the Spline/Filler subpanel to create surfaces by filling in gaps, such as a hole in an existing surface.
Option Action
entity selector Select the lines, node list, or points that define the spline/filler area.
lines
Select two or more lines. The lines do not have to form a closed loop, as disconnected lines are first connected with straight lines. Both free lines and surface edges can be selected.
node list
Select a list of nodes. A line is created through each node pair and between the first and last nodes in the list. When creating a mesh and surface with nodes, they are automatically stitched to the new surface/mesh by default.
points
Select points. The order of selection is not important. A surface is fit through the points using the outermost points as surface vertices.
Auto create (free edges only) Create the surface as soon as a closed-loop free surface edge is selected. This provides a single-click ability to close holes in an existing surface. When this option is enabled, surfaces are created in the component of the selected surface edge, and the topology is updated accordingly.

Clear this checkbox to create the surface by selecting multiple bounding lines/edges.

Keep tangency Examine surfaces attached to the selected edges, and attempt to create a surface tangent to them. This helps to form a smooth transition to the surrounding surfaces.
Note: Valid for surface edge line selection only.
Keep line endpoints for planar splines Keep line endpoints of surfaces created with closed spline/filler lines.
Create in Choose where to organize the resulting surface component.
Current Component
Organize the new surfaces to the current component. No topology updates for selected surface edges are made when this option is selected.
Lines Component
Organize the new surfaces to the same component that the selected lines already belong to. The result is unpredictable if lines from different components are selected. The topology of the new surface is updated accordingly for any selected surface edges that belong to the determined lines component.
Note: Available when the entity selector is set to lines.

## Skin Subpanel

Use the Skin subpanel to create a surface by skinning across lines. At least two input lines are required. Three or more input lines will fit a surface across all of the input lines, with the first and the last input lines defining the surface ends.
Option Action
line list Select the lines to use as input. The lines used to create the skin surface are automatically smoothed before the surface is created. As a result, the surface is created with a single face.
Auto reverse Prevent "bow tie" surfaces from being generated. The lines used to create the surface can be ordered in different directions. This results in a surface that crosses itself resembling a bow tie. Enabling this option ensures that surfaces are generated with a similar order on each side.

## Fillet Subpanel

Use the Fillet subpanel to create constant radius fillet surfaces across surface edges.
Note: You cannot create a fillet across free (red) edges between two surfaces; in such a case you must use the edge edit panel to toggle the shared edge (changing it to green).

If an edge (or edge chain) is curved, Engineering Solutions can only fillet with a radius that is smaller than the radius of the edge curve, in order to avoid the fillet intersecting itself.

In addition, care must be taken such that different fillets do not overlap (for example, if two unrelated parallel edges are filleted, the fillet radius must be small enough so that the two fillets do not interfere with each other).

There are known issues in which sometimes fillets are too short, or do not complete the trim of the surfaces being filleted. Sometimes this leads to a false decision of what should be deleted and what should be kept, and a useful surface is deleted. Many times, changing the cleanup tol in the Options panel fixes this. If it cannot be fixed this way, a workaround is to complete the trim manually using other functions; if needed, uncheck delete trimmed surface chips, create the fillet, complete the trim using manual methods, then delete what is not needed and organize the other surfaces as required.

Option Action
lines Select the lines that define the surface edges to use as input.
Auto select whole edge Select additional surface edges connected to the original selection, based on the pick angle and x stop control settings.
Pick angle
Automatically select connected edges that have an angle between adjacent surfaces sharper than the specified angle (sharp edges). Default is 22.5 degrees.
X stop control
Automatically select edges until intersections with other sharp edges are encountered.
Edit Fillet Options Access additional fillet options.
Continuous fillet
Create a single fillet for each continuous edge selection.
Clear this checkbox to split the fillet based on the surfaces connected to each continuous edge selection.
Equivalence tolerance
Specify the tolerance with which the created fillets are stitched to each other and to the original surfaces (after the original surfaces are trimmed by the fillets). It is also the tolerance with which the trimmed surface chips are stitched to each other if they are not deleted. This stitching tolerance works just like any other Geometry Tolerance values, but applies only to the fillet stitching operations.
Trim original surfaces
Trim the original surfaces, and stitch the new fillet surfaces accordingly.
Clear this checkbox to maintain the original surfaces, and create the generated fillet surfaces in a component named "Fillet".
Delete trimmed surface chips
Delete the surfaces trimmed from the original model.
Clear this checkbox to keep and organize the surfaces trimmed from the original model in a component named "Filleting chips".
Note: Applies when the trim original surface checkbox is enabled.

## From FE Subpanel

Use the From FE subpanel to create surfaces that closely fit a selection of shell elements.
Option Action
elems Select the shell elements used to generate surfaces.

In order to create surfaces from solid elements, create faces using the Faces panel and select the elements in the ^faces component.

Auto Detect Features / feature edges Choose a method for selecting features (surface edges).
Auto Detect Features
Automatically determine features.
feature edges
Specify by 1D plot elements (features).
1D plot elements must be selected to represent the edges of the surfaces to be created. It is recommended to select a closed loop of plot elements in order to best guide the algorithm. Features can be created using the Features panel.
The algorithm used by this function tries to subdivide shell elements into subsets if it does not succeed in creating a single surface through the selected shell elements.
Mesh-Based Auto Tol / Tolerance Choose a method to determine how closely the new surfaces adhere to the underlying elements. The tolerance value is the maximum distance by which the surface created differs from the selected elements at any location. This is particularly important for curved meshes.
Mesh-Based Auto Tol
Calculate the tolerance based on the average element size of the selected elements.
Tolerance
Manually specify a tolerance. A smaller tolerance usually results in a larger number of surfaces created.
Surface Complexity Affects how many surfaces are created. This option takes into account a number of factors, including the boundary shape of the area to be surfaces as well as its topology. Higher complexity values create a smaller number of more complex surfaces, but require longer calculation times to create those surfaces. Smaller values produce a larger number of smaller, simpler surfaces, but do so more rapidly.
• When the complexity is set to 1 (simplest surface), the function attempts to create surfaces with few control points. If it fails, it tries to subdivide the selected elements until it can fit a lower order surface definition to the elements.
• When the complexity is set to 10 (complex surface), the function first attempts to create surfaces with as few control points as possible. If it fails, it continues to increase the number of control points and attempts to fit one surface between the selected groups of elements. It will not try to automatically subdivide the elements.
• The recommended complexity value is 5.
Split by components Maintain boundaries between adjacent components, so that a single mesh plane will still produce separate surfaces based on the components that the elements belong to.
Associate nodes Ensure that the mesh nodes are associated to the new corresponding surfaces. This allows re-meshing of the surface to replace the original mesh instead of creating a new overlaid mesh.

## Meshlines Subpanel

Use the Meshlines subpanel to create a mesh line, which is a line on the elements of a 2D (shell) mesh that is associated with the mesh by retaining information about where it enters and exits each shell element.

For a closed chain of mesh lines, you can select the elements or nodes inside the chain and save them as collections for retrieval in other panels. This can be useful for application of loads, selection of a region to morph, or construction of CAD surfaces close to the mesh using the mesh line chain approximations as the surface borders.

Mesh lines can also be used to generate new surfaces, using a simple spline function to create the surface edges based on the mesh lines.
In addition, meshlines can be generated automatically from plot elements such as feature lines.
Option Action
Collections While not related to generating mesh lines, the collections option enable you to use existing closed mesh line chains as boundaries to quickly and easily select groups of nodes or elements that may form an irregular shape. Click Collections to select a node or element; if the selection resides inside a closed chain of mesh lines, then all of the nodes/elems within the chain will be selected automatically. Once this selection is made, you can click the selector and click save from the extended entity selection menu. Once saved, this collection of nodes or elements can be retrieved from the extended entity selection menu on other panels, such as load-related panels (forces, pressures, fluxes, and so on. )