Unigraphics NX8 - Mesh Surface

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Mesh Surface

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Ruled surface Through Curves Through Curve Mesh

Section Surface

N-Sided Surface overview

1. Ruled surface

Use the Ruled command to create a body between two sections, where the ruled shape is a linear transition between the sections.

A section can consist of single or multiple objects, and each object can be a curve, a solid edge, or a solid face.

Input Curves and output Ruled surface

Ruled surfaces can be used to create surfaces that can be unfolded onto a plane without stretching or tearing. These surfaces are used in the shipbuilding and piping industry to manufacture objects from sheet metal.

Where do I find it? Application Modeling

Toolbar Surface→Mesh Surface Drop-down→Ruled

Menu Insert→Mesh Surface→Ruled

1.1. Create a ruled surface using points

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1. Choose Insert→Mesh Surface→Ruled. 2. Select the first section.

For this example, do the following

a. On the Selection bar, set the Curve Rule to Connected Curves.

b. In the Ruled dialog box, in the Section String 1 group, click Select Curve and select the first section in the graphics window.

3. Select the second section.

For this example, do the following:

a. On the Selection bar, set the Curve Rule to Connected Curves.

b. In the Section String 2 group, click Select Curve and select the second section string in the graphics window.

4. In the Alignment group, from the Alignment list, select a method. For this example, from the Alignment list, By Points is selected.

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Default points appear on the selected sections.

You can realign the points or specify new points. 5. Click OK or Apply to create the Ruled surface.

1.2. Ruled dialog box

Section String 1 and Section String 2

Select Curve or Point

Lets you select the section string.

Specify Origin Curve

Lets you specify the origin curve for the selected section string.

Alignment

Controls the shape of the feature by defining how NX spaces the isoparametric curves of the new surface along the sections.

Isoparametric curves are generated along the U and V parameters on a face. For more information see **Unsatisfied xref title**.

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circle and a rectangle, using points to align the sections.

Specify Point option is available to let you realign the points or add new ones. You can also click Reset to restore the default alignment points.

When the Preserve Shape check box is cleared, the following additional methods are also available.

 Arc Length — Spaces isoparametric curve connection points at equal arc length intervals along the defining sections. NX uses the entire length of each curve.  Distance — Spaces points along each section at equal distances in a specified

direction. This results in isoparametric curves that all lie in planes perpendicular to the specified direction vector.

Specify Vector options are available to let you specify the direction in

which the isoparametric curves must be spaced.

 Angle — Spaces the points along each curve at equal angles around a specified axis line. This results in isoparametric curves which all lie in planes containing the axis line.

Specify Vector and Specify Point options are available in the

Axis group to let you specify the direction and location of the axis.

 Spine Curve — Places the points at the intersections of the selected sections and planes perpendicular to a selected spine curve. The extent of the resulting body is based on the limits of this spine curve.

Select Spine Curve option is available to let you select the spine curve. Spine curves that are all, or in part, perpendicular to the defining sections are

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invalid, because the intersection between the section planes and the defining curves is nonexistent, or poorly defined.

For more information on alignment options, see Alignment methods. Settings

Body Type

Lets you specify either a sheet body or a solid body for the ruled feature.

 Solid

 Sheet

To get a solid body, the section strings must form closed loops.

Preserve Shape

Preserves sharp corners by forcing a tolerance value of 0.0, overriding the default of approximating the output surface.

When you clear this check box, the G0 (Position) value is used and any sharp corners in the section strings are smoothened, but with a small radius of curvature.

Note This options is available for all alignment methods, but you can use this option only when Alignment is set to Parameter or By Points.

G0 (Position) Lets you specify a maximum distance between the input geometry and the resulting body.

2. Through Curves

Use the Through Curves command to create a body through multiple sections where the shape changes to pass through each section. A section can consist of a single object or multiple objects, and each object can be any combination of curves, and solid edges, or a solid face.

You can do the following:

 Use multiple sections to create a sheet body or solid body.

 Control the shape of the surface by aligning it to the sections in a variety of ways.  Constrain the new surface to be G0, G1, or G2 continuous with tangent surfaces.  Specify single or multiple output patches.

 Make the new surface normal to the end sections.

The Through Curves command is similar to the Ruled command. With Through Curves, you can use more than two sections and you can specify tangency or curvature constraints at the start and end sections.

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2.1. Create a through curves surface

This example shows how to create a basic Through Curves surface through six sections. Each section consists of two tangent curves.

1. On the Surface toolbar, click Through Curves or choose Insert→Mesh Surface→Through

Curves.

2. Set the Selection Intent rule.

For this example, on the Selection bar, from the Curve Rule list, Tangent Curves is selected. 3. Select a curve and click the middle mouse button to complete the selection of the first section.

For this example, the first curve at the upper end is selected.

Since you selected Tangent Curves as your selection rule, two tangent curves are added to your model and displayed as Section 1 in the List box.

4. Select additional curves and add as a new section.

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Note To avoid twisting and to ensure that each section points in the same direction, select the top curve at the upper end.

5. Click OK or Apply to create the Through Curves surface.

The surface is created using the default options in the Alignment and Output Surface Options groups.

For this example, the default Parameter alignment method is used.

6. Double-click the Through Curves surface to edit it. The Through Curves dialog box opens.

7. In the Settings group, clear the Preserve Shape option to make other alignment methods available for selection

8. In the Alignment group, from the Alignment list, select an option. For this example, from the Alignment list, Arc Length is selected. The surface isoparametric curves are realigned along the sections.

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9. On the View toolbar, set the Rendering Style Drop-Down list to Shaded with Edges. 10. Click OK to update the surface.

2.2. Create a through curves connecting surface

This example shows how to create a surface that connects two sheet bodies, is tangent continuous with the two sets of faces, and passes through the line between the two sheets.

1. On the Surface toolbar, click Through Curves or choose Insert.→Mesh

Surface.→Through Curves. 2. Set the Selection Intent rule.

For this example, on the Selection bar, from the Curve Rule list, Tangent Curves is selected. 3. Select the sections.

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For this example, the three sections are selected in the order shown, near their left ends, using the middle mouse button after you select each section.

4. In the Settings group, clear the Preserve Shape check box.

5. In the Continuity group, select a continuity constraint and specify the constraint faces. For this example, do the following:

a. Select the Apply to All check box.

b. From the First Section list, select G1 (Tangent).

Select Face becomes available.

c. Click Select Face to define the first section and select the faces of the lower sheet body.

d. From the Last Section list, select G1 (Tangent).

Select Face becomes available.

e. Click Select Face to define the last section and select the faces of the upper sheet body

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6. In the Alignment group, from the Alignment list, select a method.

For this example, from the Alignment method list, Parameter is selected. 7. Click OK or Apply to create the constrained surface.

The finished part is a sheet body created through multiple sections and is tangent to the two adjacent faces.

8. (Optional) Evaluate the result.

a. Choose Analysis→Shape→Face→Reflection. The Face Analysis - Reflection dialog box opens.

b. Select all the surface faces and click the Black and White Lines option. c. Click OK.

The surface is rendered in the selected Face Analysis style.

d. Rotate the view. Note that there are no abrupt changes in curvature at the edges for the surface.

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Tip To return to the previous rendering style, on the View toolbar, set the Rendering Style Drop-Down list to Shaded with Edges.

2.3. Through Curves dialog box

Sections

Lets you select section strings.

Specify

Origin Curve

Lets you change the origin curve in a closed loop.

List Lists section sets as you add them to the model.

You can reorder or delete them using the Move Up , Move Down or Remove

list buttons. Continuity

Apply to All Applies the continuity constraint selected for one section, to the first and last sections. First Section /

Last Section

Lets you select constraining faces and specify continuity for the selected section. You can specify G0 (Position), G1 (Tangent) or G2 (Curvature) continuity.

Select Face is available for G1 (Tangent) and G2 (Curvature) to let you select one

or more continuity constraint faces. Unconstrained Through Curves surface (green)

G2 constrained Through Curves surface to both sets of faces

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Flow Direction

Not available when all Continuity options are set to G0 (Position). This option applies only to models that use a constraint surface.

Specifies the flow direction in relation to the constraint surface.

 Not Specified — Flow direction is straight through to the opposite side.

 Isoparametric — Flow direction follows the isoparametric direction (U or V) of the constraint surface.

 Normal — Flow direction is normal to the base edge of the constraint surface. Alignment

Alignment list Controls the shape of the feature by defining how NX spaces the isoparametric curves of the new surface along the sections.

Isoparametric curves are generated along the U and V parameters on a face. For more information see **Unsatisfied xref title**.

 Parameter — Spaces the isoparametric curve connection points at equal

parameter intervals along the sections. NX uses the entire length of each curve.  By Points — Aligns points between section strings of different shapes. NX places

alignment points and their alignment lines along the sections.

Specify Point option is available to let you realign the points or add new ones. You can also click Reset to restore the default alignment points.

Note When the Preserve Shape check box is selected, you can use only Parameter and By Points alignment methods. When the check box is cleared, you can use the other available methods.

 Arc Length — Spaces isoparametric curve connection points at equal arc length intervals along the sections. NX uses the entire length of each curve.

 Distance — Spaces points along each section at equal distances in a specified direction. This results in isoparametric curves that all lie in planes perpendicular to the specified direction vector.

Specify Vector options and are available to let you specify the direction

in which the isoparametric curves must be placed.

 Angle — Spaces the points along each curve at equal angles around a specified axis line. This results in isoparametric curves which all lie in planes containing the

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axis line.

Specify Vector options and and Specify Point options and are

available in the Axis group to let you specify the direction and location of the axis.  Spine Curve — Places the points at the intersections of the selected sections and

planes perpendicular to a selected spine curve. The extent of the resulting body is based on the limits of this spine curve.

Select Spine Curve option is available to let you specify the spine curve. For more information on alignment options, see Alignment methods.

Output Surface Options

Patch Type Lets you specify whether the patches in the V direction, that is perpendicular to the sections, will be single or multiple.

 Single — Creates a single patch. The maximum number of sections is 25 and the degree in the V direction is one less than the number of strings selected.

 Multiple — Creates multiple patches.

 Match String —

Closed in V Closes the feature between the first and last sections along columns in the V direction. If the sections you select are closed and this check box is selected, and the Body Type option is set to Body, NX creates a solid body.

For multiple patches, the closed status of the body along rows (U direction) is based on the closed status of the sections. If the sections you select are all closed, the body generated is closed in the U direction.

Normal to End Sections

Makes the output surface normal to the two end sections.

 If an end section is planar, the surface is parallel to the plane normal at the end.  If an end section is a 3D curve, an average normal vector is computed, and the

surface is parallel to the average normal at the end.

 If an end section is a line, the normal vector is computed so that it points from the end section to the section next to the end section.

 Overrides the V-degree settings and makes the feature start and end perpendicular to the start and end sections.

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The curves are temporarily reparameterized through their defining points and retain any user-defined tangent values. These temporary curves are then used to create the body. This creates a simpler body with fewer patches.

Note The selected curves must be single B-curves with the same number of defining points.

 Simple — Creates the simplest curve mesh surface possible.

A simple surface with constraints avoids the insertion of extra math components when possible, thus reducing abrupt changes of curvature. It also minimizes the number of patches and the boundary noise in a surface.

Select Section Template

Available only when Construction is set to Simple.

Lets you select sections to use as the template curve. You can select any generating curve as the template, and can use it as the template for both directions.

When you select a section template, NX tries to refit the generating curves to reflect the degree and segmentation of the template and builds the surface directly from the refitted curves.

Note When using the Simple option, Distance Tolerance and Angle Tolerance as specified in the Modeling Preferences dialog box are ignored.

Settings

Body Type Lets you specify either a sheet body or a solid body for the through curves feature.

 Solid

 Sheet

To get a solid body, section strings must form closed loops. Preserve

Shape

Available only when Alignment is set to Parameter or By Points.

Preserves sharp corners by forcing a tolerance value of 0.0, overriding the default of approximating the output surface.

When you clear this check box, the G0 (Position) continuity value is used and any sharp corners in the sections are made smooth, but with a small radius of curvature.

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Note that the sharp corners at the ends of the blue curves are preserved.

Note that the sharp corners at the ends of the blue curves are made smooth.

Rebuild Available only when Construction in the Output Surface Options group is set to

Normal.

Constructs a high-quality surface by redefining the degree or segments of the sections. If the sections have poor knot placement or there are differences in degree between them, the output surface may be more complex than necessary, or the isoparameter lines may be too wavy. This could produce incorrect highlighting and prevent continuity between surfaces.

 None — Turns Rebuild off.

 Degree and Tolerance — Rebuilds the surface using a specified degree. The

degree you specify is effective in the U and V directions. Higher degree curves generally reduce the chance of unwanted inflections and sharp changes in curvature. NX inserts knots as required to achieve the G0, G1 and G2 tolerance settings.

 Auto Fit — Creates the smoothest possible surface within the specified Maximum Degree and Maximum Segments. NX tries to rebuild the surface without adding segments up to the maximum degrees.

If the surface is out of the tolerance range:

o Segments are added up to the maximum number you specify.

o If the surface is still out of the tolerance range, the surface is created and an error message is displayed.

Tolerance Specifies the tolerance values for the Continuity options to control the accuracy of the rebuilt surface in relation to the input curves.

 The G0 (Position) — Specifies the position continuous tolerance. Defaults to the Distance Tolerance.

 G1 (Tangent) — Specifies the tangent continuous tolerance. Defaults to the Angle Tolerance.

 G2 (Curvature) — Specifies the curvature continuous tolerance. Defaults to 0.1 or 10% of the relative tolerance.

2.4. Alignment methods

Alignment methods are available in many NX commands. They allow you to control how the feature flows from one section to another.

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 Arc Length — Spaces isoparametric curve connection points at equal arc length intervals along the defining sections. NX uses the entire length of each curve.

The following graphic shows how the entire section length is divided into equal arc length segments to align.

 By Points — Aligns points between sections of different shapes. NX places alignment points and their alignment lines along the sections. You can add, delete, and move the points to preserve sharp corners or otherwise refine the surface shape.

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This method gives you more control over the alignment, letting you control the specific alignment of points in each section.

Tip It is recommended that you include alignment points at sharp corners. If you do not, NX creates high-curvature, smoothed corner bodies to approximate them, and any subsequent feature operations performed on the corners or faces, such as blends, shells, or Boolean operations, may fail due to the curvature.

 Distance — Spaces points along each section at equal distances in a specified direction. This results in isoparametric curves that all lie in planes perpendicular to the specified direction vector. The defining curves determine the extents of the body, the body continues until it reaches the end of one of the defining curves.

You can specify the direction in which the isoparametric curves are spaced. Internally, NX constructs planes which are intersected with each of the defining curves to obtain the points needed for the isoparametric curves.

 Angle — Spaces the points along each curve at equal angles around a specified axis line. This results in isoparametric curves which all lie in planes containing the axis line. The extents of the body are determined by the defining curves, the body continues until it reaches the end of one of the defining curves.

Isoparametric curves all lie in planes containing the axis line

 Spine Curve — Places the points at the intersections of the sections and planes perpendicular to the selected spine curve. The extent of the resulting body is based on the limits of this spine curve. The following graphic shows the spine curve selected in yellow. Note that the surface does not extend till the entire length of the sections, but is limited by the length of the single curve selected.

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Note Spine curves which are all, or in part, perpendicular to the sections are invalid because the intersection between the planes and the sections would be nonexistent or poorly defined.  Spline Points — Creates a surface using points and tangent values for the input curves. The new

surface is required to pass through the points that define the input curves, and not the curves themselves. This changes the curve parameters and creates a smooth surface. When the curve parameters are changed, the tangent values remain the same.

Note For this method, sections must be single B-curves each with the same number of defining points.

 By Segments — Similar to the Parameter alignment method, except that NX spaces

isoparametric curves equally along each curve segment rather than at equal parameter intervals. This method produces the same number of C0 patches as the number of segments.

This method is effective if each section contains the same number of segments.

3. Through Curve Mesh

Use the Through Curve Mesh command to create a body through a mesh of sections in one direction, and guides in another direction, where the shape fits through the mesh of curves.

This command uses sets of primary curves and sets of cross curves to create a bi-cubic surface.  Each set of curves must be contiguous.

 The sets of primary curves must be roughly parallel and the sets of cross curves must be roughly parallel.

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You can do the following:

 Constrain the new surface to be G0, G1, or G2 continuous with adjacent faces.  Control cross curve parameterization with a set of spine curves.

 Locate the surface near the primary curves or cross curves, or at an average between the two sets.

Where do I find it? Application Modeling

Toolbar Surface→Through Curve Mesh

Menu Insert→Mesh Surface→Through Curve Mesh

3.1. Create a through curve mesh using curves and a

point

This example shows how to create a surface using a curve and a point as primary sets and other curves as cross sets.

1. On the Surface toolbar, click Through Curve Mesh , or choose Insert→Mesh

Surface→Through Curve Mesh.

2. Select a curve for the first primary set and click the middle mouse button or Add New Set . For this example, the curve at the top is selected.

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3. On the Selection bar, enable Snap Point and set it to End Point. 4. Select a point as the second primary set.

For this example, the end point of the curve is selected as shown.

Note You must select the primary and cross sets in consecutive order, moving from one side to the other.

5. Click the middle mouse button twice to complete the selection of primary curves.

6. Select the sets of cross curves and click the middle mouse button or Add New Set after each set.

For this example, each blue curve is selected as a set.

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7. Click OK or Apply to create the mesh surface.

3.2. Create a through curve mesh using tangency

constraints

This example shows how to create a mesh surface that is tangent to adjacent faces.

1. On the Surface toolbar, click Through Curve Mesh or choose Insert→Mesh

Surface→Through Curve Mesh. 2. Select the primary curves.

a. On the Selection bar, set the Curve rule to Single Curve.

b. In the Primary Curves group, ensure that Select Curve or Point is active.

c. Select the curve at the top as the first primary set and click the middle mouse button or

Add New Set to complete the selection.

d. Select the second primary set and click the middle mouse button or Add New Set to

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e. Select the third primary set and click the middle mouse button or Add New Set to complete the selection.

Note Ensure that all the vectors point in the same direction. 3. Select the cross curves.

a. On the Selection bar, set the Curve rule to Single Curve.

b. In the Cross Curves group, click Select Curve .

c. Select the curve on the left as the first cross set and click the middle mouse button or Add

New Set to complete the selection.

d. Select the curve on the right as the second cross set and click the middle mouse button or

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Note Ensure that all the vectors point in the same direction.

4. In the Continuity group, select a continuity constraint and specify the constraint faces. For this example, do the following:

a. Select the Apply to All check box.

b. From the First Primary list, select G1 (Tangent).

Select Face becomes available for all of the primary and cross curves.

c. Under First Primary, click Select Face and select the top tangent face.

d. Under Last Primary, click Select Face and select the bottom tangent face.

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f. Under Last Cross, click Select Face and select the right tangent face.

Note You can set any of the Continuity options to G1 (Tangent) as you have selected the Apply to All check box.

5. In the Output Surface Options group, ensure that Emphasis is set to the required value. For this example, it is set to Both.

6. In the Settings group, ensure that Rebuild is set to the required value. For this example, it is set to None.

7. Click OK or Apply to create the mesh surface.

3.3. Through Curve Mesh dialog box

Primary Curves

Lets you select sets of primary section consisting of curves, edges or points.  You must select at least two primary sets.

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 You can select a point for the first and last sets only.

Note You must select the sets in consecutive order, from one side to the other, and they must point in the same direction.

Specify

Origin Curve

Lets you change the origin curve when you select a closed loop of curves.

Cross Curves

Select Curves

Lets you select sets of cross section consisting of curves or edges.

If all the selected primary sections are closed loops, you can select the same curves for the first and last set of cross to create a closed body.

Continuity

Lets you select constraining faces at the First Primary and/or Last Primary sections, and First Cross and Last Cross sections, and specify continuity. You can constrain the mesh surface along common edges or at the interior of the faces.

Apply to All Applies the same continuity setting to the first and last sections. First Primary

Last Primary First Cross Last Cross

Lets you set continuity constraints for the first and last primary sections, and cross sections to control the accuracy of the surface in relation to the input curves.

 G0 (Position) — Position continuous tolerance. Defaults to the Distance Tolerance

 G1 (Tangent) — Tangent continuous tolerance. Defaults to the Angle

Tolerance.

 G2 (Curvature) — Curvature continuous tolerance. Defaults to 0.1 or 10 per cent of the relative tolerance.

If you select the Apply to All check box, one selection updates all settings.

Select Face

Appears when you set the continuity for any section to either G1 (Tangent) or G2 (Curvature).

Lets you select one or more constraining faces, as appropriate. Spine

Select Curve

Available only if the first and last primary sections are planar.

Lets you select a spine to control the parameterization of the cross sections. A spine can improve surface smoothness by forcing U parameter lines to be perpendicular to the spine.

The spine must be:

 Long enough to intersect all the cross sections.  Perpendicular to the first and last primary sections.  Non-perpendicular to the cross sections.

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NX calculates an average between both the primary curves and the cross

curves .

 Primary — Primary curves have more effect.

NX matches the surface to the primary curves .

 Cross — Cross curves have more effect.

NX matches the surface to the cross curves .

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Construction Lets you specify the construction method to create the surface.

 Normal — Builds a curve mesh surface using the standard procedures. Creates a surface with a greater number of patches when compared with the other methods.  Spline Points — Creates a surface using the points and tangent values at the

points for the input curves.

The curves are temporarily reparameterized through their defining points

(retaining any user-defined tangent values). These temporary curves are then used to create the surface. This creates a simpler surface with fewer patches.

Note The selected curves must be single B-curves with the same number of defining points.

 Simple — Creates the surface with or without specifying constraints. This builds the simplest surface possible, in both patches and math. The sections must have similar, simple math.

You can select a template curve for the primary sections, and one for the cross sections. If you do not select templates, NX selects them for you. The generating curves are refit to reflect the degree and segmentation of the template. If the template curve has corners, or is more than one curve, the resulting surface is split into multiple faces.

Note o Tolerance values are ignored.

o When you select the template curve, it is possible that the deviation to the original curves may be higher than normal. Use this option when deviation of the surface to the input curves is not important.

Select Primary Template /Select Cross Template

Available only when Construction is set to Simple.

Lets you select a template curve for the primary and cross sections. You can select the same curve for both directions.

When you select a template, NX tries to refit the generating curves to reflect the degree and segmentation of the template and builds the surface directly from the refitted curves. Settings

Body Type Lets you specify either a sheet body or a solid body for the through curve mesh feature.

 Solid

 Sheet

To get a solid body, section strings must form closed loops.

Rebuild Available only when Construction in the Output Surface Options group is set to

Normal.

Constructs a high-quality surface by redefining the degree and/or segments of the primary and cross sections.

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 None — Turns Rebuild off.

 Degree and Tolerance — Rebuilds the surface using a specified Degree. The

degree you specify is effective in the U and V directions. Higher degree curves generally reduce the chance of unwanted inflections and sharp changes in curvature. NX inserts knots as required to achieve the G0, G1 and G2 tolerance settings.

 Auto Fit — Creates the smoothest possible surface within the specified Maximum Degree and Maximum Segments. NX tries to rebuild the surface without adding segments up to the maximum degrees.

If the surface is out of tolerance:

o NX adds segments up to the maximum number you specify.

o Even after adding segments, NX creates it and displays an error message. Tolerance Specifies the tolerance values for the intersection and continuity options to control the

accuracy of the rebuilt surface in relation to the input curves.

 Intersection — Specifies the maximum acceptable distance between

non-intersecting sets of primary and cross sections. NX displays an error message and highlights the incorrect section pairs for up to a maximum of four pairs.

The value must be greater than zero.

 The remaining continuity options are the same as the ones in the Continuity group.

4. Section Surface

Use the Section Surface command to create surfaces through sections of curves or edges using conic construction methods.

Section features are created from a series of conic curves which are calculated by sectioning the specified curves and faces. The calculated section curves are then swept to create the body.

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Where do I find it?

Application Modeling, Shape Studio

Toolbar

Section Surface

Surface→Section Surface

Menu

Insert→Mesh Surface→ Section Insert→Mesh Surface→ Sections

4.1. Input parameters for section surfaces

Start and End guides

Start and end guides specify the start and end geometry for the section surface and the surface flow. You can select the curve or edge at either end without considering the directional.

Start guide End guide

Slope control

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End slope curve

 Start and end faces whose shape controls the slope of the section surface from its selected start or end guide.

Start face End face

 A single apex curve or edge whose shape controls the slope of the section surface from both its selected start and end guides.

 Apex curve

Spine curve

When you create a section surface, a spine curve is necessary to control the orientation of the calculated sectioning planes. A spine curve can reduce distortions caused by uneven distribution of the parameters on the guide curves.

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A simple spine leads to a simple arrangement of U parameter curves, and reduces the risk of self-intersection or overly complex surfaces.

The examples shows the U parameter curves of section surfaces resulting when a line is selected as the spine curve and when an arc is selected as a spine curve.

Spine Curve Section Surface

Note  The end you select determines the direction of the surface.

 A spine curve works best when it is approximately parallel with the starting and ending curves.

Rho values

Rho is a scalar value that controls the fullness of each conic section.

Apex curve Start edge curve End edge curve

The height or fullness of the section (distance D1) is calculated by the value entered for rho using this formula:

rho = D1/D2

A small value of rho (near zero) produces a very flat conic. A large value of rho (near 1) produces a more pointed conic.

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The slope at each end is defined by an apex curve.

A spine curve determines the orientation of the calculated sectioning planes. Start guide End guide Apex curve Shoulder curve Spine curve Preview surface Ends-Slope-Shoulder

Creates a section surface that starts on the first guide curve, passes through an interior shoulder curve, and ends on the end guide curve.

The slope is defined at the start and end by two independent slope control curves. A spine curve determines the orientation of the calculated sectioning planes.

Start guide End guide Start slope curve End slope curve Shoulder curve Spine curve

Preview surface Fillet-Shoulder

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Creates a section surface that forms a smooth blend between two respective curves that lie on two bodies. The surface starts on the first guide curve, and is tangent to the first body. It ends on the second guide curve, is tangent to the second body, and passes through the shoulder curve.

A spine curve determines the orientation of the calculated sectioning planes. Start guide End guide Start face End face Shoulder curve Spine curve Preview surface Ends-Apex-Rho

Creates a section surface that starts on the start guide curve and ends on the end guide curve.

The slope at each end is defined by a selected apex curve. The fullness of each conic section is controlled by a rho value.

A spine curve determines the orientation of the calculated sectioning planes Start guide End guide Apex curve Spine curve Preview surface Ends-Slope-Rho

The slope is defined at the start and end by two independent slope control curves. The fullness of each conic section is controlled by the corresponding rho value.

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Spine curve Preview surface Fillet-Rho

Creates a section surface that forms a smooth blend between two respective curves that lie on two bodies. The fullness of each conic section is controlled by the corresponding rho value.

A spine curve determines the orientation of the calculated sectioning planes Start guide End guide Start Face End Face Spine curve Preview surface Ends-Apex-Hilite

Creates a section surface that starts on the start guide curve, ends on the end guide curve, and is tangent to a line calculated with the highlight curves.

The slope at each end is defined by an apex curve.

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Start guide End guide Apex curve

Start highlight curve End highlight curve Spine curve

Calculated tangent line and highlight curve endpoints

Preview surface Ends-Slope-Hilite

Start guide End guide Start slope curve End slope curve Start highlight curve End highlight curve

Spine curve

Calculated tangent line and highlight curve endpoints Preview surface

Fillet-Hilite

Creates a section surface that forms a smooth blend between the respective start and guide curves, which lies on two bodies, and are tangent to a line calculated using the highlight curves.

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End face

Start highlight curve End highlight curve

Spine curve

Calculated tangent line and highlight curve endpoints Preview surface

Four-Point-Slope

Creates a section surface that starts on the start guide curve, passes through two interior curves, and ends on the end guide curve.

A slope control curve defines the starting slope.

A spine curve determines the orientation of the calculated sectioning planes Start guide End guide

First interior curve Second interior curve Start slope curve End Spine curve

Curve endpoints (typical)

Preview surface Five-Point

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Creates a section surface using five existing curves as control curves.

The surface starts on the first guide curve, passes through three interior guide curves, and ends on the end guide curve.

A spine curve determines the orientation of the calculated sectioning planes. Start guide End guide

First interior curve Second interior curve Third interior curve Spine curve

Preview surface Three-Point-Arc

Creates a section surface from a start guide curve, passes through an interior guide curve, and ends on an end guide curve.

A spine curve determines the orientation of the calculated sectioning planes. The section of the section surface is a circular arc.

First interior curve Spine curve

Curve endpoints (typical) Preview surface

Two Point Radius

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Counterclockwise rotation direction Preview surface

End Slope Arc

Creates a section surface that starts on the start guide curve and ends on the end guide curve. The slope is determined at the start by a selected control curve.

A spine curve determines the orientation of the calculated sectioning planes. The section of the sheet is a circular arc.

Start guide End guide Start slope curve Spine curve Preview surface Point-Radius-Angle-Arc

Creates a section surface by defining a start guide curve on a tangent face, and the laws for the curvature radius and the angle that the surface spans.

A spine curve determines the orientation of the calculated sectioning planes.

The default position of the surface is in the direction of the face normal. You can change the surface to the opposite side of the tangent face.

The angle can vary from –179 to –1 degrees, or from 1 to 179 degrees, but it cannot pass through zero. The radius must be greater than zero.

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Start guide Start face Spine curve

Endpoints (typical) Radius angle law Preview surface Circle

Creates a full circular section surface from the start guide curve. The radius is defined by a law, and a spine curve determines the orientation of the calculated sectioning planes. You can also specify an optional second orientation curve.

The radius can be zero at either or both ends of the surface, but it cannot be zero elsewhere. Start guide

Orientation guide (optional) Spine curve

Radius law Review surface Circle Tangent

Creates a circular section surface that is tangent to a face using a start guide curve, a tangent face, and a law to define the radius of the surface.

You can select multiple faces.

You can create the surface in either the fillet arc or the cover arc direction.

Start guide

Start face (tangent face for the start of slope control) Spine curve

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Ends-Slope-Cubic

Creates an S-shaped section surface that forms a smooth cubic blend between a start guide curve and an end guide curve.

Start guide End guide Start slope curve End slope curve Spine curve Preview surface Fillet-Bridge

Creates a section surface forming a bridge between two curves on two sets of faces. You can control the shape of the fillet-bridge surface by doing the folloiwng:

 Use the Section Control Continuity options to change the shape by matching tangents (G1),

curvatures (G2), or flow (G3) at the ends of the fillet-bridge section. You can make further adjustments to the shape using the Depth and Skew options until you get the shape you want.  Select a spline whose general form determines the shape of the fillet-bridge surface.

Start guide End guide Start face End face

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Start shape curve (optional) Spine curve

Preview surface Linear-Tangent

Creates a linear section surface tangent to one or more faces. The surface is created by selecting a tangent face, a starting curve, and a spine.

Start guide Start face Spine curve Preview surface

4.3. Create a section surface with shoulder curves

This example shows how to create a section surface that passes through a start guide curve, and end guide curve, and a shoulder curve. The slopes at the start and end are defined by two slope control curves.

1. On the Surface toolbar, click Section Surface or choose Insert→Mesh Surface→Section

Surface.

2. In the Section Surface dialog box, in the Type group, from the Type list, select Ends-Slope-Shoulder.

The Select Start Guide option in the Guides group is active.

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6. Click the middle mouse button.

The Select Start Slope Curve option in the Slope Control group is active.

7. In the graphics window, select a curve which controls the slope of the section surface from the selected start guide.

The Select Ends Slope Curve option is active.

9. In the graphics window, select a curve which controls the slope of the section surface from the selected end guide.

Start slope curve End slope curve

The Select Shoulder Curve option in the Section Control group is active.

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Shoulder curve

The Select Spine Curve option in the Spine Curve group is active.

13. In the graphics window, select the spine curve to define the orientation of the sectioning planes. A preview of the section surface is displayed.

Spine curve

Preview surface

14. (Optional) You can do the following to adjust the shape of the section surface:

o In the Section Control group, click the Show Alternate Solutions option to see

different possible surfaces that can be created. This option is available only if an alternate solution is possible.

o In the Spine Curve group, click the Reverse Direction option.

15. Click OK or Apply to create the section surface.

4.4. Create a fillet-shoulder section surface

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1.

Section Surface. 2.

In the Section Surface dialog box, from the Type list, select Fillet-Shoulder. 3. Start guide End guide 4. Start face End face 5. Shoulder curve 6. Spine curve

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4.5. Create a fillet-hilite section surface

This example shows how to create a surface that starts at the upper edge of the surface on the left and ends at the upper edge of the surface on the right.

The resulting surface is tangent to the two existing surfaces. An existing rectangle is used to define the limit of the new surface.

1.

In the Section Surface dialog box, from the Type list, select Fillet-Hilite.

3. Start guide End guide 4. Start face End face

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6.

Spine curve

4.6. Create a five-point section surface

This example shows how to create a section surface that starts on the start guide curve, passes through three interior guide curves, and ends on the end guide curve.

A spine curve determines the orientation of the calculated sectioning planes. 1.

In the Section Surface dialog box, from the Type list, select Five-Point.

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3. Start guide End guide 4. Interior guide 1 Interior guide 2 Interior guide 3 5. Spine curve

4.7. Create a two-point radius section surface

This example shows how to create a surface with circular sections of a specified radius.

The surface is created in a counterclockwise direction from the spine direction, from the start guide curve to the end guide curve.

1.

In the Section Surface dialog box, from the Type list, select Two Point Radius.

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4.

End guide

5. Section Control group settings:

 Law Type = Linear

 Start = 50

 End = 120

6.

Select the Spine Curve

7.

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4.8. Section Surface dialog box

Type

Type list

Specifies the method used to create a section surface.

The available options that appear in the Section Surface dialog box depend on the Type you select from the list.

Note For more information about the input parameters that control the resulting section surface, see Types of section surfaces.

Ends-Apex-Shoulder

Ends-Slope-Shoulder

Fillet-Shoulder

Creates a section surface that forms a smooth blend between two curves that lie on two respective bodies.

Ends-Apex-Rho

Ends-Slope-Rho

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Ends-Slope-Hilite

Fillet-Hilite

Creates a section surface that forms a smooth blend between the start and guide curves, which lies on two respective bodies, and are tangent to a line calculated with the highlight curves.

Four-Point-Slope

Creates a section surface that starts on the start guide curve, passes through two interior curves, and ends on the end guide curve.

Five-Point

Creates a section surface using five existing curves as control curves.

Three-Point-Arc

Creates a section surface from a start guide curve, passing through an interior guide curve, and ending on an end guide curve.

Two-Point-Radius

Creates a surface with circular sections of a specified radius.

End-Slope-Arc

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the end guide curve.

Point-Radius-Angle-Arc

Creates a section surface by defining a start guide curve on a tangent face, and laws for the curvature radius and the angle that the surface spans.

Circle

Creates a full circular section surface from the start guide curve.

Circle-Tangent

Creates a circular section surface tangent to a face using a start guide curve, a tangent face, and a law to define the surface's radius.

Ends-Slope-Cubic

Creates an S-shaped section surface that forms a smooth cubic blend between a start guide curve and an end guide curve.

Fillet-Bridge

Creates a section surface forming a bridge between two curves on two sets of faces.

Linear-Tangent

Creates a linear section surface tangent to one or more faces. Guides

Specifies the start and the end geometry for the section surface.

You can select the curve or edge at either end without considering the direction.

Select Start Guide / Select End Guide

Lets you select one or more connected edges or curves as the section guide to specify where the surface creation flow begins.

Slope Control

Controls the shape of the section surface from either or both the start or end edges, from a single apex curve, or from the start or end faces.

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Select Apex Curve

section surface from both its selected start and end guides.

Select Start Face / Select End Face

Lets you select a face whose shape controls the slope of the section surface from its selected start or end guide.

Reverse Direction is available.

Section Control

Controls how the sections in a section surface are defined. Depending on the Type you choose, these options can range from a curve, edge, or face selection, to the defining of laws.

For detailed Section Control option information, see Section Surface — Section Control options. Spine Curve

Controls the orientation of the calculated sectioning planes.

Select Spine Curve

Lets you select a curve or edge that defines the spine curve of the section surface.

Note  The end you select for the spine curve determines the direction of the surface.

 A spine curve works best when it is normal to the guide curves, and approximately parallel with the starting and ending curves.

Reverse Direction

Reverses the direction of the spine curve and consequently, the section surface.

Settings

Lets you control the shape of the sections in the U direction, set rebuild and tolerance options, and create an apex curve.

For detailed information on the Settings group, see Section Surface — Settings options.

4.9. Section Surface — Section Control options

Section Control

Select Shoulder

Available when Type is set to Apex-Shoulder, Slope-Shoulder, or Ends-Slope-Shoulder.

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Curve from the start guide to the end guide at creation time. Slope is controlled either by selected slope curves or faces.

Select Start Highlight Curve / Select End Highlight Curve

Available when Type is set to Ends-Apex-Hilite, Ends-Slope-Hilite, or Fillet-Hilite. Lets you select a curve or edge that is used as the start or end highlight curve.

Highlight is a method to control the peak of a section surface. The section surface is tangent to an internally calculated surface defined by the start and end highlight curves. Slope is controlled either by selected slope curves or faces.

Section Method

Appears when Type is set to: Ends-Apex-Rho, Ends-Slope-Rho, Fillet-Rho, Circle Tangent, or Fillet Bridge.

Specifies an additional method to control the section surface, apart from the input curves.

Type Available options

Ends-Apex-Rho, Ends-Slope-Rho, and Fillet Rho

Rho

Lets you define the shape of the conic section by defining a rho law using one of the standard options of the Law Subfunction.

For more information, see Law Types. Least Tension

Computes the rho value from the input geometry according to a least tension condition. In most cases this produces an ellipse. When the angle between the chord and the tangent is the same at each end of the conic, the result is a circular arc.

Fillet-Bridge Continuity

Lets you control the shape of the section surface by specifying separate start and end continuity parameters, G1 (Tangent), G2 (Curvature), or G3 (Flow).

Inherit Shape

Makes the section surface tangent continuous to the two face sets, and its general shape in the U direction is inherited from a curve that you select.

For more details and additional shape control options that are not shown here, see Section Surface — Section Control options. Circle Tangent Fillet Arc

Defines the orientation of the section surface to the tangent face in the fillet arc direction.

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Lets you specify a rho value for the sections in the surface by defining a law. For more information, see Rho values.

Radius Law

Appears when the Type is set to Two-Point-Radius, Point-Radius-Angle-Arc, Circle, or Circle Tangent.

Lets you define a law that specifies a radius value for the sections in the surface.

Angle Law

Appears when the Type is set to Point-Radius-Angle-Arc or Linear-Tangent. Lets you define a law that specifies an angle value for the sections in the surface.

Law Type

Specifies the type of law to use when creating the section surface.

Depending on the Law Type you select, different options appear to let you define that law.

For more information, see Law Types.

Value

Lets you specify a value for the law you are defining. For a rho law this would be a numeric value. For a radius or angle law this would be a value in degrees.

If the Law Type requires multiple values, Start and End boxes appear instead of a Value box.

Show Alternate Solutions

Cycles through multiple results when multiple results are possible for the section surface based on the selected objects and option sets.

Alternate solution for the Linear-Tangent type of section surface

Start guide

4.10. Section Surface — Settings options

Note These options are available only in the Settings group.

For information on Section Surface options, see Section Surface dialog box. Settings

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U Degree

Controls the shape of the sections in the U direction (perpendicular to the spine curve).

Section surface Spine curve

Conic surface sheet with edge curves drawn in the U direction

Conic

Produces a true and exact conic shape with no reversals in curvature. Acceptable rho values range between 0.0001 and 0.9999. Parameterization can be very nonuniform.

Note The Conic option does not work for Rho and Ends-Slope-Cubic section types. If you choose Conic with one of these section types, NX ignores the setting and uses Cubic instead.

Cubic

Produces roughly the same shape as with the Conic option, but with a better surface parameterization. Flow lines are distributed more evenly along the entire curve, but without producing exact conic shapes.

Quintic

Produces surfaces that are degree 5 and C2 (curvature continuous) between patches.

V Degree Rebuild

Controls the degree and shape of the section in the V direction (parallel to the spine curve). Note Input curves with poor knot placement or differing degrees create complex surfaces

of poor continuity. None

Does not redefine degree and knot points of the input curves. Degree and Tolerance

Optimizes the surface in the V direction by specifying the number of degrees for the input curves.

Degree Lets you specify the degrees from 2 to 24. Higher degree curves generally reduce the chance of unwanted inflections and sharp changes in curvature.

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NX attempts to build the surface without segments until the maximum degree is reached. If the tolerance cannot be met with the maximum degree, segments are added up to the number defined for maximum segments.

Maximum Degree

Specifies the maximum number of degrees to use when redefining the input curves in the V direction.

Maximum Segments

Specifies the maximum number of knot points to use when redefining the input curves in the V direction.

The default settings are taken from the Advanced Rebuild Options.

Tolerance

Sets tolerances for surface continuity, letting you control the accuracy of the surface in relation to the input curves. The surface will not deviate from the input curves greater than the values specified for these tolerances.

G0 (Position)

Position continuous tolerance. Defaults to the Distance Tolerance. G1 (Tangent)

Tangent continuous tolerance. Defaults to the Angle Tolerance. G2 (Curvature)

Curvature continuous tolerance. Defaults to 0.1 or 10% of the relative tolerance. The construction of the body involves an approximation process, which is controlled by the distance tolerance that you specify.

The distance tolerance is the maximum allowable distance between a procedure defined conic body and the approximation constructed by the software.

Note Ensure that you use a valid deviation tolerance value. If the value is too small, the resulting body contains many more patches than is necessary, or the software may not be able to construct a body that meets the input tolerance.

Create Apex Curve

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This can be helpful when diagnosing problems, because the apex curve can reveal surface discontinuities that can occur when using separate slope controls.

Note If the selected Type requires you to specify an apex curve as input, the Create Apex Curve option is ignored.

The following graphic shows a sheet body created using the Ends-Slope-Rho type, with Create Apex Curve selected.

Start guide curve End guide curve Start slope curve End slope curve Spine curve

Software generated apex curve Note To completely define the section surface, you must specify enough data to meet the

five conditions required to define a conic (such as, 3 points and 2 slopes, or 2 points, 2 slopes, and a rho value).

4.11. Section Surface — Fillet-Bridge options

Note These options are available when Type is set to Fillet-Bridge.

For information on Section Surface options not described here, see Section Surface dialog box. Section Control

Section Method

Lets you choose the method to create the sections for the Fillet-Bridge type of surface.

Continuity

Creates the sections based on setting continuity constraints for either ends of the fillet-bridge, where they meet the selected start and end faces. After an initial fillet-bridge section preview appears, you can change its depth, skew and continuity. You cannot do this when you select the Inherit Shape method.

Inherit Shape

Creates the sections so they are tangent continuous to the selected start and end faces. The general shape is inherited from one (or if needed, two) curves specified with the Shape Curves options.

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The sections are curvature continuous to the respective face sets, and are smoothly connected with up to two differentiations.

G3 (Flow)

The sections are G3 continuous to the respective face sets, and are smoothly connected with up to three differentiations. They may have a higher degree of freedom of shape and represent a more complex section in the V

direction.

Depth and Skew

Appears when Section Method is set to Continuity. Control Region

Localizes the effects of the Depth and Skew sliders on the section surface. Entire

Affects the entire section surface. Start

Affects only the section surface area near the start face. End

Affects only the section surface area near the end face. Depth

Controls how much the curvature of the sections affects the fillet-bridge surface. The value is a percentage of the curvature effect. Works similarly to the Depth option in Bridge Curve.

Move the slider to change the shape of the sections in the fillet-bridge. The greater the value, the more pronounced is the curvature of the section. The lower the value, the flatter the section. The default value is 50.

Skew

Controls the location on the fillet-bridge surface of the maximum curvature (or reversal of curvature). The value represents the percentage of the distance along the bridge from start to end. Works similarly to the Skew option in Bridge Curve. Shape Curves

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Select Start Shape Curve /Select End Shape Curve

Appears when Section Method is set to Inherit Shape.

Lets you select a curve or edge that defines the general shape of the section surface, from the start face or end face respectively.

Spine Curve

Select Spine Curve

Required if Section Method is set to Continuity, but optional if Section Method is set to Inherit Shape.

Lets you select a curve or edge that defines the spine curve of the section surface.

Start Flow Direction/ End Flow Direction

Appears when Section Method is set to Continuity.

Lets you separately specify the flow direction for both the Start Face and the End Face options.

Not Specified

Makes the flow direction from the Start Face or End Face straight through to the other side.

Perpendicular

Makes the flow direction from the Start Face or End Face perpendicular to the base edge used to specify the fillet-bridge.

Iso Line U

Makes the flow direction of the Start Face or End Face follow the U curve of the base surface used to specify the fillet-bridge.

Iso Line V

Makes the flow direction from Start Face or End Face follow the V curve of the base surface used to specify the fillet-bridge.

5. N-Sided Surface overview

Use the N-Sided Surface command to create a surface enclosed by a set of end-connected curves. You can do the following:

 Build a surface with an unrestricted number of curves or edges that form a simple, open or closed loop, and assign continuity to outside faces.

 Remove holes or gaps in surfaces that are not four-sided.

 Specify the constrain faces and interior curves to modify the shape of the N-sided surface.  Control the sharpness of the center point of the N-sided surface, while maintaining continuity

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The command is useful for designers, stylists, and product designers who want to smoothly patch gaps between surfaces without having to trim, untrim, or change edges of the outside surfaces.

Where do I find it?

Application Modeling, Shape Studio

Toolbar Surface→N-sided Surface

Menu Insert→Mesh Surface→N-sided Surface

5.1. Create a trimmed n-sided surface

This example shows how to create a trimmed N-sided surface to close the gap in the corner of a sheet body. You will define the UV orientation of the surface by specifying a rectangle.

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2. On the Surface toolbar, click N-sided Surface or choose Insert→Mesh Surface→N-sided Surface to open the N-Sided Surface dialog box.

3. In the Type group, selectTrimmed from the list.

4. In the UV Orientation group, select Area from the list.

5. Under UV Orientation, in the Define Rectangle subgroup, click Specify 1st Point .

6. In the graphics window, click and drag to create a box around the opening.

7. In the Outer Loop group, click Select Curve and select the edges of the opening in the graphics window.

8. In the Constraint Faces group, click Select Face and select the faces adjacent to the opening in the graphics window.

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Tip To improve performance, clear the Preview check box when you select multiple constraint faces.

9. In the Shape Control group, ensure that the Constraint, Continuity option is set to G1 (Tangent).

10. In the Settings group, select the Trim to Boundary check box.

The preview shows the area outside the outer loop of the surface is trimmed. 11. Click OK or Apply.

Tip If the resulting corner surface contains any unwanted bulges, first create a bridge curve between existing faces and select it as an interior curve in the UV Orientation group.

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5.2. Create a triangular n-sided surface

In this example, a triangular N-sided surface is created to close the gap in the sheet body.

1. On the Surface toolbar, click N-sided Surface or choose Insert→Mesh Surface→N-sided

Surface to open the N-Sided Surface dialog box. 2. In the Type group, select Triangular from the list.

3. In the Outer Loop group, click Select Curve and select the curve in the graphics window.

A preview of the surface appears.

Note the triangular faces in the N-sided surface.