unigraphics nx8 - mesh surface

[NX8-HELP] MESH SURFACE 1

Mesh Surface drive24ward (meslab.org/mes)

Mesh Surface View a topic

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

This example shows how to create a surface between circular and rectangular sections.



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.



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

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**.

When the Preserve Shape check box is selected, you can use only the Parameter and By



Points alignment methods.

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 sections of different shapes. NX places

alignment points and their alignment lines along the sections.

In this example, a Ruled surface is created between sections of different shapes, a

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



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.



Where do I find it?


Toolbar Surface→Through Curves

Menu Insert→Mesh Surface→Through Curves

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.

For this example, each set of tangent curves is selected and added as a new section.



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.



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.



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.


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



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.



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

Select Curve

or Point

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



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



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.

Note When you select Normal to End Sections, the Continuity options are unavailable.



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

Normal — Creates a curve mesh surface using the standard procedures. Creates a

body or surface with a greater number of patches when compared with the other

Construction options.

Spline Points — Creates a body using the points and tangent values at the points

for the input curves.

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.

Preserve Shape on Preserve Shape off



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.

Following is a list of the methods. Not all are available in all commands.



Parameter — Spaces the isoparametric curve connection points at equal parameter intervals

along the sections. NX uses the entire length of each curve. Parameter values vary according to

curvature; the tighter the curvature, the closer is the interval.

The following graphic shows the grid display of how the isoparametric lines are spaced when you

use the Parameter alignment method.

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.

The following graphics shows a surface that transitions from a circular section to a rectangular one.



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.



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.

You can use a point instead of a curve for the first or last primary set.




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?


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.



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.

As you select each set of cross curves, the preview is updated to display the surface.



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

complete the selection.



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

Add New Set to complete the selection.



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.


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.

e. Under First Cross, click Select Face and select the left tangent face.



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.



Select Curve

or Point

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.



Output Surface Options

Emphasis Specifies that the surface passes through either the primary curves, or cross curves, or an

average of the two.

Note This option applies only if a primary and cross curve pair do not intersect.

Both — Both primary and cross curves have equal effect.

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 .



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.



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 create incorrect highlighting and prevent continuity between

surfaces. Using Rebuild options, you can make the required changes and build the

surface again.

Note The same options are available in the Primary tab, and the Cross tab.

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.

The following graphic shows the Five-Point type of section surface used to create the surface of a wing.



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

You can control the shape of the section surface using the following:



Start and end slope curves or edges whose shape controls the slope of the section surface from the

selected start and end guides.

Start slope curve

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.



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.

Rho value = 0.5 Rho value = 0.75

When the U Degree is set to Conic, rho values between 0.0001 and 0.9999 are allowed.



When the U Degree is set to Cubic or Quintic, the maximum rho value allowed is 0.75.

4.2. Types of section surfaces

Ends-Apex-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 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.


Start guide

End guide

Start slope curve

End slope curve

Shoulder curve

Spine curve

Preview surface

Fillet-Shoulder



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.


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.




Start guide

End guide

Start slope curve

End slope curve

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.


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.




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

Creates a section surface that starts on the start guide curve, ends on the end guide curve, and is tangent to




Start guide

End guide

Start slope curve

End slope curve


End highlight curve

Spine curve


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.




Start guide

End guide

Start face

End face


End highlight curve

Spine curve


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.


Start guide

End guide

First interior curve

Second interior curve

Start slope curve

End Spine curve

Curve endpoints (typical)

Preview surface

Five-Point



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.


Start guide

End guide


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.


The section of the section surface is a circular arc.

Start guide

End guide


Spine curve


Preview surface

Two Point Radius

Creates a surface with circular sections of a specified radius.

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



the end guide curve.

Start guide

End guide

Spine curve


Counterclockwise rotation direction

Preview surface

End Slope Arc


The slope is determined at the start by a selected control curve.


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.


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.



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

Preview surface



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



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.

3. In the graphics window select a curve to define the start guide.

4. Click the middle mouse button.



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

5. In the graphics window, select a curve to define the end guide.

Start guide

End guide


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.

11. In the graphics window, select an interior curve through which the surface must pass.



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

This example shows how to create surface that forms a smooth blend between two curves that lie

respectively on two bodies.



The surface:

Starts on the start guide curve

Is tangent to the selected start face.

Ends on the end guide curve.

Is tangent to the selected end face.

Passes through the shoulder curve.

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



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.

Section Surface.

2.

In the Section Surface dialog box, from the Type

list, select Fillet-Hilite.

3.

Start guide

End guide

4.

Start face

End face



5.

Start Highlight curve

End Highlight curve

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.


1.

Section Surface.

2.

In the Section Surface dialog box, from the

Type list, select Five-Point.



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.

Section Surface.

2.

In the Section Surface dialog box, from the Type list,

select Two Point Radius.



3.

Start guide

4.

End guide

5.

Section Control group settings:

Law Type = Linear

Start = 50

End = 120

6.

Select the Spine Curve

7.

Click Reverse Direction to create a concave surface.



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

Creates a section surface that starts on the first guide curve, passes

through an interior shoulder curve, and ends on the end guide curve.

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.

Fillet-Shoulder

Creates a section surface that forms a smooth blend between two curves

that lie on two respective bodies.

Ends-Apex-Rho

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


Ends-Slope-Rho





Fillet Rho

Creates a section surface that forms a smooth blend between two curves

that lie on two respective bodies.

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.

Ends-Slope-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.

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


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





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.

You can select curves or edges at either end without regard for directional sense.



Select Start Slope

Curve / Select End

Slope Curve

Lets you select a curve or edge whose shape controls the slope of the section

surface from the selected start or end guide respectively.

Select Apex Curve

Lets you select a single curve or edge whose shape controls the slope of the

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 Ends-Apex-Shoulder, Ends-Slope-Shoulder, or Ends-

Slope-Shoulder.

Lets you select an interior curve or edge through which the surface passes on its sweep



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.



Cover Arc

Defines the orientation of the section surface to the tangent

face in the cover arc direction.

Rho Law

Appears when the Type is set to Ends-Apex-Rho, Ends-Slope-Rho, or Fillet-Rho, and

when the Section Method is set to Rho.

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



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 Ends-Slope-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.



Knots are inserted as required to achieve the G0, G1, and G2 tolerance

settings.

Auto Fit

Optimizes the surface in the V direction by specifying the maximum number of

degrees and the number of segments of the input curves.

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

Creates and displays the apex curve internally created by NX.



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.

Continuity Appears when Section Method is set to Continuity.



Sets the level of continuity where the sections meet the start faces and end faces.

G1 (Tangent)

The sections are tangent continuous to the respective face sets, and are

smoothly connected with up to one differentiation.

G2 (Curvature)

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



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.


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

constraints.



The following graphic shows different ways used to fill the void area in a group of faces.

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.

1. Orient the WCS so that the XC-YC plane is approximately parallel to the opening.



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.

Note that the surface curves a little to follow the continuity of the constrain face.



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.



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.

4. In the Constraint Faces group, use Select Face to specify the constrain faces.



5. In the Shape Control group, under Constraint, ensure that Flow Direction is set to Not

Specified and Continuity is set to G1 (Tangent).

6. In the Settings group, select the Merge Faces if Possible check box.

7. Click OK.

5.3. N-Sided Surface dialog box Type

Type list Lets you specify the type of N-sided surface you can create.

Trimmed — Creates a single surface covering the entire region within a closed loop

of selected curves or edges.

Triangular — Creates a surface of individual, triangular patches within a closed

loop of selected curves or edges, each consisting of the triangular region between

each side and a common center point.

Outer Loop



Select

Curve

Lets you select a closed loop of curves or edges to serve as a boundary for construction of

the N-sided surface.

The closed loop represents the profile of the boundary for the new surface, and can consist

of any number of curves or edges.

Note If you select adjacent curves or edges that are tangent continuous, you may have bad

surfaces, particularly when you create a Trimmed type of the N-sided surface.

Constraint Faces

Select Face

Lets you select faces to add tangency and curvature constraints to the new surface.

Selecting a constraint face automatically matches the position, tangency and curvature of the

surface with that face.

When the constraint face is selected, the N-sided surface matches the curvature of the

constraint face .

When the constraint face is not selected, the N-sided surface is flat.

Type-specific options

Trimmed UV Orientation

Lets you specify the direction for the new surface as it is built. If you do not specify

UV orientation, NX generates the surface automatically.

Spine

Defines the V orientation of the new surface using a spine curve. The U

directional isoparametric lines of the new surface are oriented perpendicular

to the selected spine curve.

o Select Curve

Lets you select the spine curve.

Vector

Defines the V orientation of the new surface using a vector. The UV



orientation of the new N-sided surface follows the given vector direction.

o Specify Vector

Lets you specify the direction.

Area

Lets you create a new surface connecting the boundary curves.

Interior Curves

o Select Curve

Lets you specify the boundary curves. The new surface is created by

creating sheet bodies between the connected boundary curves.

o Specify Origin Curve

Lets you specify the origin curve in the set of interior boundary

curves.

o Add New Set

Lets you specify a new set of interior boundary curves.

o List

Lists the specified sets of interior curves.

Define Rectangle

o Specify 1st Point

Specify 2nd Point

Lets you specify the first and second diagonal points to define the

rectangle for the new WCS plane. The region is projected toward the

selected loop profile to form the initial boundary of the rectangular

surface.

The two points are not associative with the N-sided surface that is

created. They are used only to define the region and the orientation.

Shape Control



Lets you control the continuity and flatness of the new surface.

Center Control

Available for:

o Spine and Vector UV orientation when the constraint continuity is

G0 (Position).

o Area UV orientation when the constraint continuity is G1 (Tangent)

and constraint faces are selected.

Lets you control the flatness of the surface around the center point.

The Center Flat slider is available to let you move the surface up or down.

Drag the slider to change the center point. The default value is 50 which

represents the mid or flat position. When you drag the slider left or right of

the mid point, the outward starting angle from the center point changes.

When the slider is at the mid point, the outward starting angle from the center

point is 180 degrees.

Constraint

Lets you set the Continuity of the N-sided surface to match with the selected

constraint faces.

G0 (Position) and G1 (Tangent) options are available.

Settings

Trim to Boundary — Trims the surface to the specified boundary curves or edges.

Triangular Shape Control

Lets you change the shape of the new surface.

Center Control — Specifies the position and tilting option for the center

point.

o Position — Lets you change the position of the center point.

X, Y, Z, and Center Flat sliders are available.

Drag the X, Y and Z sliders to move the position of the center point

of the surface. Drag the Center Flat slider to make the center point

sharper or smoother.



The default value of the X, Y and Z sliders is 50 that represents the

mid, or flat position, and the default value of the Center Flat slider is

100.

Center Control set to Position where X = 5, Y = 50 and Z = 50.

The center point moves in the indicated direction.

Top view shows that the center point has moved.

o Tilting — Lets you change the tilt of the plane where the center point

lies.

X, Y and Center Flat sliders are available.

When you drag the X or Y sliders, the plane normal of the center

point is tilted in the direction indicated. The center point position does

not change.

Center Control set to Tilting where X = 100 and Y = 50.

The plane of the center point tilts in its X direction.



Top view shows that the center point has not moved.

Flow Direction

Specifies the flow direction of the curves used to create the resulting N-sided

Surface.

Not Specified

Makes the UV parameterization of the resulting sheet equidistant towards the

center-point.

Perpendicular

Makes the V directional isoparametric lines of the resulting surface start from

the outside edge in the direction perpendicular to the edge. Available only if

all the curves or edges in the loop are at least tangent continuous.

Iso U/V Line

Makes the V directional isoparametric lines of the resulting surface start from

the outside edge in the direction following the U/V direction of outside face.

Available only when boundary constraints are tangent or curvature and faces

are selected.

Adjacent Edges

Makes the V directional isoparametric lines of the resulting surface follow

the side edges of constraining faces.

Constraint Faces

Lets you set the continuity of the N-sided surface with the selected constraint face.

G0 (Position), G1 (Position) and G2 (Curvature) options are available.

Settings

Merge Faces if Possible



Trims the surface to the specified boundary curves or edges.

Treats tangent-continuous portions of the loop as single curves, and builds one face

for each tangent-continuous section.

To create one face for each curve or edge in the loop, clear this check box.

Settings

G0

(Position)

Specifies the position continuous tolerance. Defaults to the Distance Tolerance.

The surface does not deviate from the input curves greater than the specified value.

G1

(Tangent)

Specifies the tangent continuous tolerance. Defaults to the Angle Tolerance.

The surface does not deviate from the input curves greater than the specified value.

Mục lục Mesh Surface ................................................................................................................................................................ 1

1. Ruled surface .................................................................................................................................................... 1

1.1. Create a ruled surface using points .......................................................................................................... 1

1.2. Ruled dialog box ....................................................................................................................................... 3

2. Through Curves ................................................................................................................................................ 5

2.1. Create a through curves surface .............................................................................................................. 6

2.2. Create a through curves connecting surface ............................................................................................ 8

2.3. Through Curves dialog box ..................................................................................................................... 11

2.4. Alignment methods ................................................................................................................................ 15

3. Through Curve Mesh ...................................................................................................................................... 18

3.1. Create a through curve mesh using curves and a point ......................................................................... 19

3.2. Create a through curve mesh using tangency constraints ..................................................................... 21

3.3. Through Curve Mesh dialog box ............................................................................................................ 24

4. Section Surface ............................................................................................................................................... 28

4.1. Input parameters for section surfaces ................................................................................................... 29

4.2. Types of section surfaces ........................................................................................................................ 32

4.3. Create a section surface with shoulder curves ....................................................................................... 41

4.4. Create a fillet-shoulder section surface .................................................................................................. 43

4.5. Create a fillet-hilite section surface ........................................................................................................ 45

4.6. Create a five-point section surface ......................................................................................................... 46

4.7. Create a two-point radius section surface ............................................................................................. 47

4.8. Section Surface dialog box ..................................................................................................................... 49



4.9. Section Surface — Section Control options ............................................................................................ 52

4.10. Section Surface — Settings options .................................................................................................... 54

4.11. Section Surface — Fillet-Bridge options ............................................................................................. 57

5. N-Sided Surface overview ............................................................................................................................... 59

5.1. Create a trimmed n-sided surface .......................................................................................................... 60

5.2. Create a triangular n-sided surface ........................................................................................................ 63

5.3. N-Sided Surface dialog box .................................................................................................................... 64

unigraphics nx8 - mesh surface

Documents

middle mouse button

unsatisfied xref title

rendering style drop

poor knot placement

auto fit creates

choose insertmesh surfacen

calculated sectioning planes

spine curve places