ProE Surfacing - Module 6

Module 6: Surface Modeling using Swept Blends

Lab Exercises

If you are ready to start on the exercises for this module, please click the links below.

Exercise 1: Designing an Intake Manifold Exercise 2: Designing the Impeller Body of a Pump (Challenge) Exercise 3: Creating a Lamp Fixture (Challenge)

Lecture Review

If you would like to review a text-based version of the materials presented in this lecture, please click here.

IntroductionPro/ENGINEER Wildfire 3.0 offers basic tools such as Sweeps, Blends, and advanced tools such as Swept Blends and Variable Section Sweeps that enable you to design complex and controllable shapes using cross-sections and trajectories. Cross-sections are important when visualizing, representing, and creating forms. These advanced tools are particularly useful when you use dimensions and constrained parameters as design references.  In this module, you learn to create surface models using the Swept Blend tool, which enables you to create surfaces using multiple sections and a single trajectory.

ObjectivesAfter completing this module, you will be able to:

Describe the differences between Sweep, Blend, and Swept Blend tools. Create surface features using the Swept Blend tool. Control the cross-sectional area. Describe the rules to create Swept Blends.

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Reviewing Sweeps and Blends Sweep — You can create a surface feature by sweeping a sketched cross-

section along a trajectory that can be sketched or selected. The cross-section remains normal to the trajectory at all times when the swept geometry is created.

Blend – You can create a blended surface feature by placing a series of two or more planar sections in space. These sections can be parallel to each other or placed at an angle about the X, Y, and Z-axes with respect to each of the previous sections. Pro/ENGINEER joins the sections together at their edges with transitional surfaces to form a continuous feature. For blends, the cross-section can vary, but there is no provision to follow a specific trajectory.

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Swept Blends The Swept Blend offers the best characteristics of both the sweeps and the

blends. Multiple and varying cross-sections can be placed along a selected trajectory. Furthermore, the section does not have to stay normal to the trajectory.

Geometry required for creating the Swept Blend – A Swept Blend requires a single trajectory (referred to as the Origin trajectory) and multiple sections.

Defining trajectory and sections – To define the Origin trajectory of the swept blend, you can select a sketch, a chain of datum curves, or a chain of edges. You then select or sketch the sections to be blended at specified segment vertices or datum points on the Origin trajectory. To orient a sketched section, you can specify the rotation angle for each section.

Swept Blends (cont.) When creating a swept blend feature, you must select an existing trajectory.

o The trajectory can be a sketch, an edge, or a datum curve.

You then must either select existing sections or sketch sections within the swept blend feature.  

o A minimum of two cross-sections must always be defined or selected.

When sketching cross-sections: o For Open Trajectories, you must create sections at the start and end

points. o For Closed Trajectories, sections must be sketched at the start point

and at least one other location. o For sections defined at other locations, other than the start or end, you

can locate cross-sections at natural vertices (anywhere a curve is

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broken or changes type) or at any on-curve datum points that have been placed.

o Orienting sketched cross-sections - After sketching a section within the Swept Blend tool, you can enter a rotation value about the Z-axis of the sketch. The sketch will then be able to twist about the trajectory. You can also select an additional X-Trajectory which will be used to locate the positive X direction of the sketch. 

When selecting cross-sections: o Define a minimum of two sections. They need not be at the start or the

end of the trajectory. Their location is set based on where the original geometry is placed relative to the trajectory, as is their orientation.

Trajectory Options Trajectory options influence the orientation of the cross-sections along the

trajectory. o Normal to Origin Trajectory:  The section plane remains normal to

the Origin trajectory throughout its length. This is the default option for the swept blend. 

o Constant Normal Direction: The section plane normal vector remains parallel to a specified planar reference along the length of the swept blend.

o Normal To Secondary Trajectory: An additional trajectory is selected and used to determine the orientation of the section.

o Normal To Projection: The Section plane remains normal to the 2-D projection of the Origin trajectory on a specified reference plane.

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Modifying the Shape of Swept Blend Surface FeaturesThe Blend Control element enables you to select a method for controlling the shape of the swept blend between its sections. The following options are available:

Set Perimeter – Control the shape of the feature by controlling the perimeter between the sections. If two consecutive sections have equal perimeters, the system attempts to maintain the same cross-section perimeter between these sections. For sections that have different perimeters, the system uses smooth interpolation along each curve of the trajectory to define the perimeter of the feature between its sections.

o Center Crv – (Optional with Set Perimeter) Shows a curve connecting the centroids of the feature’s cross-sections.

Set Cross-section Area – Controls the shape of the feature through control points and area values. You can add or select points on the trajectory to change the area of the section at that point. Note that this option can only control an area at the locations selected between sections. The area at the section is controlled by the section itself. 

About the figures: The first figure shows the default swept blend with three sections. The cross-

sectional area is specified only at the three cross-sections used to build the model.

The second figure shows the addition of a cross-sectional area definition at PNT1 and PNT2. The cross-sectional area at these points has been kept decreased at PNT1 and increased at PNT2. The section at the defined points is scaled to match the desired cross-sectional area values. A blended surface is created by the system using these cross-sections.

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Specifying Tangency in Swept Blend Surface Features Tangency can be used as an option to modify the shape of the swept blend.

For each entity in the cross-section(s) at the start and/or end, the swept blend geometry can be forced to be tangent to other pre-existing geometry.

About the figures: The figures show the change in the shape of the swept blend geometry after

the tangency condition has been added. In the last figure, the surfaces created are tangent to the adjoining surfaces.

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Rules in Creating Swept BlendsSwept blends share these limitations with sweeps and blends: Sweeps:

A sweep cannot intersect itself. Intersections can take place as the result of many different geometric configurations. A trajectory intersecting itself is one example. Another is a sweep going around a corner that is so tight that the sweep intersects itself on the inside of the corner.

A sweep, on a non-tangent corner of a trajectory will cause the sweep to miter itself (create beveled edges at an angle) at that point.

Blends: Start points must line up, otherwise twisting may occur, resulting in

a possible failure of the feature. Each section must have the same number of points unless blend vertices are

used.Additionally, swept blends have this limitation:

When using the Normal to Secondary trajectory option, the second trajectory must consist entirely of tangent entities.

About the figures: Figure 1 shows an invalid trajectory. The trajectory intersects itself. Figure 2 shows the lined-up start points while defining the sections for the

swept blend. It also highlights the equal number of segments in each section. The circular section is divided into four segments, to match the square at the other end.

Exercise 1: Designing an Intake ManifoldObjectivesAfter successfully completing this exercise, you will know how to:

Create sections to define a Swept Blend surface. Use sections with an unequal number of segments. Use an area graph to control the cross-sectional area.

ScenarioYou are designing the intake manifold using the sections and the trajectory defined in a drawing. To ensure smooth flow, you have to design the model with continuous surfaces. Also, you have to ensure that the shape can be mathematically controlled. 

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Completed Manifold Model

Task 1. Open the MANIFOLD.PRT and review its existing geometry.

1. In the Folder Browser  , browse to the module_06 folder. 2. Click the module_06 folder and select Set Working Directory. 3. Open the MANIFOLD.PRT. 4. Turn on the display of all datum features if necessary.

o Notice the curve lying on the TOP datum plane. o This curve defines the trajectory. o Also, note the four datum curves that define the first rectangular cross-

section of the swept surface.

Manifold Part

Task 2. Create the second section.

1. Start the Sketch Tool  from the feature toolbar. 2. Select the RIGHT datum plane as the sketching plane and click Sketch.

o Sketch a circle with a diameter of 1.5, as shown in the following figure.

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Sketching the Second Section

 3. Since the first section (existing rectangle sketch) is composed of four

entities, divide the circle into four entities by performing the following steps:

o Click Centerline  from the Sketcher toolbar. o Sketch two centerlines through the center of the circle and at an angle

of 30 degrees, as shown in the following figure.

o Click Divide Entity  from the Sketcher toolbar. o Select the lower-left intersection of the centerline and the circle to

create the start point. o Select the remaining intersections.

Dividing the Circle in Four Segments

 4. Click Complete Sketch  from the Sketcher toolbar.

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Task 3. Create a Swept Blend Surface feature using the existing geometry.

1. Press CTRL + D to view the default orientation. 2. Click Insert > Swept Blend.

o Select the trajectory, as shown in the following figure.

Selected Trajectory

 3. Turn off the display of all datum features. 4. Select the Sections tab in the dashboard.

o Change the section option from Sketched Sections to Selected Sections.

o Select the Rectangular section. o Select Insert from the Sections tab. o Select the circular section. o The feature preview should appear, as shown in the following figure.

If the feature preview appears twisted, the first intersect in the circular section was not

created in the proper location. You can drag the start point to the proper location.

Swept Blend Preview

 5. Click Complete Feature .

Task 4. Create a flat mounting flange for the manifold, using a Fill surface on a

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datum plane.

1. Click Edit > Fill. o Right-click and select Define Internal Sketch.

2. Move the Sketch dialog box aside and start the Datum Plane Tool   from the feature toolbar.

o Right-click to query and select the rectangular sketch as the Through reference for the datum plane, as shown in the following figure.

Selecting the Datum Curve

 3. In the Datum Plane dialog box, click Properties and type FLANGE as the

name of the datum plane. o Click OK.

Datum Plane for the Flange Surface

 4. Notice datum plane FLANGE is automatically selected as the sketching plane.

o Select datum plane RIGHT as the reference plane. o Select Right for the orientation direction. o Click Sketch.

5. Click Close in the References dialog box. o Click Yes to continue without defining sketching references.

6. Click Entity Offset from Edge  from the Sketcher toolbar. o Select Chain as the type.

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o Select two adjacent edges of the rectangular datum curve. o Click Next if necessary and click Accept when the entire rectangle is

selected. o Type 0.4 as the offset value towards the outside, as shown in the

following figure.

Offsetting the Rectangular

Datum Curve

 7. Click Complete Sketch  from the Sketcher toolbar.

o Click Complete Feature  .

Resultant Flat Flange Surface

 8. With the Fill surface still selected, click Edit > Trim.

o Select the inner rectangular curve. o Flip the direction, as shown in the following figure. o Click Complete Feature  .

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Fill Surface Trimmed

Task 5. Merge the flange surface to the part.

1. Press CTRL and select the swept blend surface and the rectangular surface, as shown in the following figure.

Selecting Surfaces to be Merged

2. Start the Merge Tool  from the edit toolbar. o Click Complete Feature  .

  Merged Quilt

Task 6. Create rounds to smooth out the edges.

1. Start the Round Tool  from the feature toolbar.

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o Press CTRL and select the four edges shown in the following figure. o Edit the radius to 0.5.

Selecting the Edges

 2. Click Complete Feature  .

Final Manifold Quilt

Task 7. Define the location where you want to control the area of the cross-section. Create two datum points before the swept blend.

1. Drag the Insert Indicator   in the model tree directly before Swept Blend 1.

o Start the Datum Point Tool  from the feature tool bar. o Right-click to query and select the entire trajectory curve. o Edit the offset ratio value to 0.35, as shown in the following figure.

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Creating NT

 2. Right-click to query and select the entire trajectory curve to add another

point. o Edit the offset ratio value to 0.90, as shown in the following figure.

Creating NT

 Notice that the length ratio can be applied to the entire curve or an individual segment. You

can also specify real length or offset from a reference.

3. Click OK to complete creating the datum points. o Enable datum point display.

Points to Locate Cross-sectional Control

 4. Right-click Insert Indicator  in the model tree and select Cancel.

o Click Yes at the message prompt to resume all features.

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Task 8. Control the shape of the cross-section using the datum points as references for new cross-sectional area values.

1. In the model tree, right-click Swept Blend 1 and select Edit Definition. o Select the Options tab from the dashboard. o Select the Set Cross-Section Area Control option. o Select PNT1 and type 3.0 as the cross-sectional area value. o Notice there was a small change to the shape of the swept blend

feature.

Changing Area at PNT1

 2. Press CTRL and select datum point PNT2.

o Type 2.25 as the cross-sectional area value. o Notice that there was a small change to the shape of the swept blend

feature.

Modified Graph

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3. Select the area value for PNT1 in the dashboard. o Type 5 as the new value.

4. Select the area value for PNT2 in the dashboard. o Type 3 as the new value.

5. Click Complete Feature . o Disable datum point display. o Notice the change to the shape of the swept blend feature.

Modified Swept Blend

6. Click Save  from the main toolbar and click OK. 7. Click File > Erase > Current > Yes.

This completes the exercise.

Exercise 2: Designing the Impeller Body of a Pump (Challenge)ObjectivesAfter successfully completing this exercise, you will know how to:

Define tangency of a swept blend surface to the adjoining surface. Create a swept blend in multiple features to get around the limitation of a

sweep not being able to intersect itself.

ScenarioYou are assigned a project to create an impeller volute for a turbo compressor. The aerodynamicists have provided you with the outlet for the volute as well as the cross-sections desired at five stations around the perimeter of the model. You are asked to finish the 3-D model of the volute to complete the gas path. 

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Completed Impeller Body

Task 1. Open the model.

1. In the Folder Browser  , click on the module_06 folder to view its contents.

2. Open the IMPELLER_BODY.PRT.

Impeller Body Part

Task 2. Build one-half of the impeller body using a Swept Blend surface.

1. Click Insert > Swept Blend. o Select the curve for the trajectory, as shown in the following figure.

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Trajectory for Swept Blend

 2. Right-click and select Selected Sections.

o Select the sketch, as shown in the following figure.

Selecting the First Section

 3. Right-click and select Insert Section.

o Select the sketch, as shown in the following figure.

Selecting the Second Section

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4. Right-click and select Insert Section.o Select the sketch, as shown in the following figure.

Selecting the Third Section

 5. Click Complete Feature .

Resultant Swept Blend

Task 3. Build the other half of the impeller body using another swept blend.

1. Click Insert > Swept Blend > Surface. o Select the curve for the trajectory, as shown in the following figure.

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Selecting the Trajectory

 2. Right-click and select Selected Sections.

o Select Section 1, as shown in the following figure. o Right-click and select Insert Section. o Repeat the procedure to select Section 2 and Section 3, also shown in

the following figure. 

  Selecting Sections 1, 2, 3

 3. Click Complete Feature .

Task 4. Merge the surfaces together into one quilt.

1. Press CTRL and select the two swept blend surface features previously created.

o Start the Merge Tool  from the edit toolbar. o Click Complete Feature  .

Merging the Quilts

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2. With the merge feature still selected, press CTRL and select the cylindrical quilt.

o Start the Merge Tool  from the edit toolbar.

o In the dashboard, click Change First Quilt Side  . o The feature preview should look, as shown in the following figure. o Click Complete Feature  .

Merging the Quilts

Task 5. Apply tangency between the swept blend surfaces.

1. Select XSECTION1 from the model tree. o Press SHIFT and select XSECTION5. o Right-click and select Hide.

2. Click Analysis > Geometry > Dihedral Angle from main menu. o Select the edge shown in the following figure. o Drag the scale handle from 1 to approximately 30. o Notice the minimum (1.23) and maximum (1.81) values in the dialog

box: The sections are not tangential. o Close the Dihedral Angle dialog box.

Analyzing Dihedral Angle

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 You will learn more about the Dihedral Angle and other analysis tools in a later module.

3. In the model tree, right-click Swept Blend 2 and select Edit Definition. o Select the Tangency tab. o Change the condition for the Start Section from Free to Tangent. o Select the corresponding adjacent surface for the first segment, as

shown in the following figure.

Specifying First Tangency Reference

 4. Select the corresponding adjacent surface for the second segment, as shown

in the following figure.

Specifying Second Tangency Reference

 5. Select the corresponding adjacent surface for the third segment, as shown in

the following figure.

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Specifying Third Tangency Reference

 6. Change the condition for the end section from Free to Tangent.

o Repeat the previous procedure by selecting the corresponding adjacent surfaces as each segment highlights.

o Click Complete Feature .

7. Click Analysis > Geometry > Dihedral Angle. 8. Select the edge shown in the following figure. 9. Notice that the minimum and maximum values has reduced considerably

(close to 0) after applying the tangency condition to the swept blend surface.

Checking the Dihedral Angle

10. Click Save  from the main toolbar and click OK. 11. Click File > Erase > Current > Yes.

This completes the exercise.

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Exercise 3: Creating a Lamp Fixture (Challenge) After successfully completing this exercise, you will know how to:

Create swept blends with both selected and sketched sections. Utilize various options for swept blends.

ScenarioIn this exercise, you complete the LAMP_FIXTURE model, by creating two swept blends using the supplied sections and trajectories.

Task 1. Open the LAMP_FIXTURE.PRT.

1. From the Folder Navigator , click Working Directory . o Double-click on LAMP_FIXTURE.PRT to open the model.

o Click Datum Planes  from the main toolbar to enable their display.

LAMP_FIXTURE.PRT

2. Click Datum Planes  from the main toolbar to disable their display. 3. Select the following sketches from the model tree and take note of their

location. o Trajectories TRAJ_1 and TRAJ_2. o Sections SEC_1, SEC_2, and SEC_3. o Click on the background to de-select all items.

Task 2. Begin the creation of a swept blend.

1. Click Insert > Swept Blend from the main menu.

You can add the Swept Blend icon to the feature toolbar using Tools > Customize Screen.

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2. Select the trajectory curve, as shown in the following figure. o Click the yellow arrow to flip the start point on the trajectory (also

shown in the following figure).

Trajectory Selected

 3. Select the Sections tab in the dashboard.

o Change the section type from Sketched Sections to Selected Sections.

o Select the first section, as shown in the following figure.

Selecting First Section

 4. Click Insert from the Sections tab.

o Select the second section, as shown in the following figure.

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Selecting Second Section

Task 3. Insert an intermediate section.

1. Select Section 1 from the Sections tab. o Click Insert. o Notice that a new Section 2 has been added after Section 1 in the

sections list. o Click Remove.

Most of the options in the Sections tab can be quickly accessed by using the right mouse

button.

2. Select the Section 1 note from the model to activate it.o Right-click over the model and select Insert Section. o Select the section shown in the following figure. o Notice the refined shape of the blend.

New Section Added

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Task 4. Control the cross-sectional area at a specified location.

1. Select the Options tab from the dashboard. o Click Set Cross-Section Area Control. o Select the vertex shown in the following figure.

Selecting a Vertex

 2. Type 1 for the Area value in the Options tab.

o Type 4.5 for the Area value, and observe the change in the sweep profile, as shown in the following figure.

Changing Area Values

Task 5. Complete the swept blend feature.

1. Click Complete Feature . 2. Select anywhere on the model background to de-select all items. 3. Press CTRL and select TRAJ_1, SEC_1, SEC_2, and SEC_3 from the model tree.

o Right-click and select Hide.

o Click Datum Planes  from the main toolbar to disable their display.

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Swept Blend Completed

Task 6. Redefine the swept blend to create a twisting effect.

1. Select the swept blend feature if necessary. o Right-click and select Edit Definition. o Select the Section 3 note to activate it. o Drag the start point upward 2 vertices, as shown in the following

figure.

Dragging the Start Point

 2. Click Complete Feature .

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Swept Blend Redefined

Task 7. Begin a second swept blend, using sketched sections.

1. Click Insert > Swept Blend from the main menu. 2. Select the trajectory curve, as shown in the following figure.

Trajectory Selected

 3. Select the Sections tab in the dashboard.

o Select Sketched Sections if necessary. o Notice that Section 1 is highlighted. o Read the current prompt in the message window. o Select the start point of the trajectory as the location for Section 1, as

shown in the following figure.

Selecting First Section Location

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Task 8. Sketch the first section.

1. Click Sketch from the Sections tab. o Click Entity From Edge . o Select Chain as the Type. o Select the upper horizontal edge of the octagon. o Select the next edge to the right. o If necessary, click Next to highlight the chain as shown in the following

figure. o Click Accept. Notice the start point is created in the upper right.

Selecting Edge Chain

 2. Click Complete Sketch . 3. Click Insert from the Sections tab.

o Select the end point of the trajectory as the location for Section 2, as shown in the following figure.

Selecting Second Section Location

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Task 9. Sketch the second section.

1. Click Sketch from the Sections tab.

o Click Sketcher Palette . o Double-click on the Octagon thumbnail. o Click anywhere in the sketch to initially place the section.  o Drag the location handle to snap to the crosshair intersection. o Type a scale of 1 and click Accept Changes . o Click Close from the Sketcher Palette dialog box. 

Octagon Section Placed

 2. Right-click and select Dimension.

o Create a diameter dimension, as shown in the following figure. o Select the 1.00 dimension and click Delete to resolve the conflict. o Edit the new diameter dimension to 8.

Modified Section

 3. Select the vertex shown in the following figure.

o Right-click and select Start Point.

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Selecting a New Start Point

 4. Click Complete Sketch .

Task 10. Insert an intermediate section.

1. Select the Section 1 note from the model to activate it.o Right-click and select Insert Section.

o Click Datum Points  from the main toolbar to enable their display. o Select point PNT0, as shown in the following figure.

Selecting New Section Location

 2. Right-click and select Sketch.

3. Click Sketcher Palette . o Using previous techniques, place and dimension an octagon, as shown

in the following figure. o Relocate the start point (also shown in the following figure).

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Completed Sketch

 4. Click Complete Sketch .

Section Added

Task 11. Specify rotation (twist) angles for the sections.

1. Select the Sections tab from the dashboard, if necessary. o Select Section 2. o Type -45 for the Rotation value.

2. Select Section 3. o Type -90 for the Rotation value.

Use Sketched Sections for a swept blend when the angular twist control is needed between

sections.  Unlike Selected Sections, the angle values become editable dimensions, and you are

not restricted to dragging the start point to the next vertex of the section.

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Section Rotation Angles Specified

Task 12.

Control the cross-sectional area at a specified location.

1. Select the Options tab from the dashboard. o Click Set Cross-Section Area Control.

o Click Datum Points  from the main menu to disable their display. o Select the vertex shown in the following figure.

Selecting a Vertex

 2. Type 4 for the Area value in the Options tab.

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Changed Area Value

Task 13. Specify the tangency for the start of the swept blend.

1. Select the Tangency tab from the dashboard. o Change the Boundary Condition for the Start Section from Free to

Tangent. o Select the solid surface adjacent to the highlighted edge, as shown in

the following figure.

Selecting Surface for Tangency

 2. Continue selecting the remaining seven adjacent surfaces.

o Notice that the first surface highlights in red after all eight have been selected.

Task 14. Complete the swept blend feature.

1. Click Complete Feature . 2. Select TRAJ_2 from the model tree.

o Right-click and select Hide. o Click View > Visibility > Save Status.

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Swept Blend Completed

Task 15. Merge the surfaces and create a thicken feature.

1. Press CTRL and select the two swept blend surfaces from the model.

o Start the Merge Tool  from the edit toolbar.o Click Complete Feature .

Merging Surfaces

 2. With the merge feature still selected, click Edit > Thicken.

o Edit the thickness value to 0.20. o Click Complete Feature .

Completed Model

 3. Press CTRL + S and then press ENTER to save the model.

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4. Click File > Close Window.

Task 16. View the models in the assembly.

1. From the Folder Navigator , click Working Directory .o Double-click on LAMP.ASM to open the model.

LAMP.ASM

 The LAMP.ASM contains the swept blend fixture model that you actually worked on.  The black

appearance was previously applied to the LAMP_FIXTURE.PRT in the context of the assembly.

2. Press CTRL + S and then press ENTER to save the model. 3. Click File > Close Window. 4. Click File > Erase > Not Displayed > OK.

This Completes the exercise.

SummaryAfter successfully completing this module, you should know how to:

Describe the differences between Sweep, Blend, and Swept Blend tools. Create surface features using the Swept Blend tool. Control the cross-sectional area. Describe the rules to create Swept Blends.

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