Download - ProE Surfacing - Module 5

Module 5: Surface Modeling using Boundaries

Lab Exercises

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

Exercise 1: Creating Boundary Surfaces on the Shaver Exercise 2: Creating Surfaces on the Air Filter Cover (Challenge) Exercise 3: Adding Control Points to the Air Filter Cover (Challenge) Exercise 4: Creating Draft Surfaces (Challenge)

Lecture Review

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

IntroductionSurfaces by boundaries are one of the most powerful and flexible surface creation tools that you can use to capture design intent. You use them while creating continuous surface features. As the name suggests, the surfaces are created with the boundary edges defined with curves or edges. You can apply edge tangency conditions for aligning the shape of the surface with the adjoining geometry. You can modify the structure of surfaces by modifying the curves that define the shape of the surfaces or the surfaces directly.You can also use direct surfacing tools such as, Blend Section to Surfaces, to reduce the multiple steps required for creating such features. These tools are used to reduce the design development time. Solid and surface modeling techniques are used together effectively for modeling a part quickly with greater feature control.

ObjectivesAfter completing this module, you will be able to:

Describe boundary surfaces. Describe types of boundary surfaces. Create a surface with boundaries. Apply constraints at the boundary edges of surfaces. Create blending surfaces using Blend tools.

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Surface Modeling using Boundaries You can create a surface by defining its boundaries in one or two directions.

You can select datum curves, datum points, solid, or surface edges as boundaries.

You can apply Edge Tangency conditions for aligning the shape of the surface with the adjoining geometry. Continuity conditions like tangency or curvature continuity are usually defined at the ends of the surface. This help you define constraints to the surface with the adjacent surfaces, edges, or curves. You can modify the surface geometry to smoothen the surface patches that are created.

You can create different types of surfaces using boundaries. o Blended: The surface is a blend between reference entities that are

selected, such as datum curves. You can create blended surfaces in one or two directions.

o Conic: The surface created follows the geometric rules of conics. These are used in special cases such as styling products where a smooth transition is required between surfaces.

o Approximate: The blended surface is approximated through some fit curves and by specifying a smoothening factor.

o N-sided: The surface is defined using more than four boundary edges. o Advanced options: Create advanced surfaces using the Advanced

option in the Insert drop-down menu.

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Blended Surfaces Blended surfaces are used to create a smooth quilt that connects several

sections. The first and last entities selected in each direction define the surface boundary. Adding more section entities in between enables you to define the surface shape with greater control.

Blended surfaces can be created with curves available in one direction. The surface created thus passes through the curves.

Blended surfaces can also be created when a curve network is available in two directions. The surface created thus passes through the curves in both directions. For blended surfaces defined in two directions, the outer boundaries must form a closed loop.

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Manipulating Blended Surfaces Any surface created with default system conditions may not satisfy your

design need. You will have to tweak the shape to get the desirable surfaces. Pro/ENGINEER Wildfire provides tools that enable you to manipulate the blended surfaces while you are in Feature Creation mode.

You can manipulate blended surfaces by: o Controlling the Boundary Conditions – Defining tangency or

curvature continuity conditions at the boundary edges. o Defining Blend Control Points – You change the patch structure

using different options. o Defining the Boundary Influence – Placing the surface in

conjunction with other surfaces and defining how the newly created surface is influenced by the other geometry lying next to it.

Controlling the Boundary Conditions You control the boundary conditions of the blended surface using the

following types of edge alignments: o Free – No tangency conditions are set along the boundary. o Tangent – The blended surface is tangent to the reference surface

along the boundary. o Curvature – The blended surface has curvature continuity across the

boundary. o Normal – The blended surface is normal to the reference surface or

datum plane. For checking boundary conditions, you can use curvature plots as shown in

the slides.About the figures:

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Free Edge Alignment – Notice the curvature plot at a cross-section of the created surface. It has zero value.

Tangent Edge Alignment – Notice the curvature plot at a cross-section of the created surface. Notice the joined curvature at the surface joint. The curvature is unequal at the joint.

Curvature Edge Alignment – Notice the curvature plot at a cross-section of the created surface. The heights of the curvatures are matched at the joint.

Normal Edge Alignment – Notice the curvature plot at a cross-section of the created surface.

Defining Control Points Surfaces are affected by the condition of the geometry that is used as

references to define them. When there are curve segments present in the curves used to define a surface, the surface displays patches.

Sometimes the number of patches in the surfaces are far greater than what is acceptable. Generally, surfaces with patches pose modeling problems in downstream features, for example, creating a shell. It is always advisable to create a smooth blended surface rather than surfaces with patches. Pro/ENGINEER enables you to remove unnecessary patches using Control Points.

You use the Control Points option to: o Connect logical sets of vertices. o Eliminate unnecessary small surfaces and extra edges thus achieving a

smoother surface. o Avoid undesirable twisting and stretching of surfaces.

To blend the points, you can select: o Vertices of the datum curves or edges used to define the boundary.

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o Datum points that lie on the curve.

To add control points to a boundary blend surface you can: o Select the Control Points option from the Boundary Blend dashboard. o Add sets of points on each boundary to control the patch definitions. o Define them automatically by selecting the other re-parameterization

options.

Defining the Boundary Influence Most surfaces that are created are never placed in isolation. They are placed

in conjunction with the other surfaces. Also you need to create shapes in which surfaces flow from one to the other smoothly.

You can manipulate the boundaries of the blended surface by defining the boundary influence of the adjacent surfaces. This constraint is used in situations where surface defining curves are available only in one direction. In such a case, you can control the geometry of a blended surface so that the shape and properties of the side curves are propagated into the shape of the blended surface.

In essence, the use of boundary influence makes the side edges of the blended surface tangent to the side edges of the reference.

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Conic Surfaces Conic surfaces are used quite often in styling products where a smooth

transition is required between surfaces. It is a best practice to use conic fillets over radial fillets to prevent problems related to curvature at the surface transitions. You can use conic fillets to resolve such problems. Conics are widely used in auto styling.

In the top figures in the slide, a radius fillet and a conic fillet are defined on the edge of the surfaces. Notice the curvature at the edge where the fillet begins. In the radius fillet, the curvature abruptly changes, but in the conic fillet the curvature gradually increases. There is a smooth transition from the flat surface to the fillet.

You can create a conic surface by picking two opposite boundary curves and one control curve.

The control curve can be a Shoulder or Tangent curve. o Shoulder Curve—The surface passes through the control curve. In

this case, the control curve defines the location of conic shoulders for each cross-section of the surface.

o Tangent Curve—The surface does not pass through the control curve. In this case, the control curve defines the line, which passes through the intersections of the conic sections’ asymptotes.

Rules for selecting curves/edges, while creating conic surfaces: o Only single-segment composite curves can be selected as boundary or

control curves. o When selecting with the Chain option, the chain cannot have more

than one edge/curve component.

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Conic Surfaces (cont.) You can sketch complex shapes such as elliptical, parabolic, and hyperbolic

sections for conic surfaces by using conic arcs. To create a conic arc, you select the location for the first endpoint, the location for the second endpoint, and a third intermediate or shoulder location.

You can dimension conic sections using the RHO parameter to control the shape of the cross-sections.

o Using the RHO parameter: You can dimension the endpoints and specify a value for the RHO parameter (similar to a radius dimension) to control the size and shape of the conic. You can only specify values between 0.05 and 0.95 for the RHO parameter. Based on the values, you get different shapes for the conic section:

0.05 to < 0.50 = Elliptical 0.5 = Parabolic > 0.50 to 0.95 = Hyperbolic Ö2-1 = Quadrant of an Ellipse

Pro/ENGINEER Wildfire automatically defines the tangency conditions at the edge of the conic surface based on the Shoulder/Tangent curve and the RHO value.

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Approximate Blended Surfaces Use Approximate Blend Surfaces when you need to create a surface from

open loops of curves, which may also be influenced by some other curve geometry.

Pro/ENGINEER enables you to create a surface feature using curve definitions that approximate the surface. This becomes useful with free flowing surfaces where the surface definition is more visual, which is also how you want to control it. The smoothening factor can be parametrically defined by values, which control the influence of the approximated curves or fit curves through the surface geometry.

This option is particularly useful when you want to use curves generated using laser-scanning techniques, where machine inaccuracies or electronic noise often distort the data.

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Approximate Blended Surfaces (cont.) You can specify the smoothness factor of approximate blended surfaces. The

smooth parameter specifies the number of points of the given curve that the system should use. The range of smoothness is 0 to 1, with 1 being the smoothest (that is, it uses the fewest number of points).

You can also specify the number of surface patches in the U and V directions. The greater the number of patches, the closer the surface will be to the selected curves. If Pro/ENGINEER cannot construct the surface using the number of patches specified, you can enter a different number of patches.

In the pictures shown on this slide, the display of the mesh surface has been switched on for better clarity of the geometry.

N- Sided Surfaces The N-Sided Surf option enables you to create blended surfaces from more

than four bounding curves or edges. You can specify the boundary conditions of the surface as follows:

o Free — No tangency conditions are set along the boundary. o Tangent — The blended surface is tangent to the reference surface

along the boundary. o Normal — The blended surface is normal to the reference surface or

datum plane. The shape of the N-sided patch depends on the geometry of the boundaries

to be patched together. For some boundaries, the N-sided patch may produce geometry with undesirable shape and characteristics. For example, bad geometry may occur if:

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o The boundaries have inflections. o The angles between the boundary segments are very large (more than

160 degrees) or very small (less than 20 degrees). o The boundaries consist of very long and very short segments.

If the N-sided patch does not create a satisfactory geometry, you can either create a series of N-sided patches on a smaller number of boundaries, or use the Blended Surf functionality.

Advanced Blend Options During the course of a product's development, sometimes you encounter

situations where general solid modeling practices fail and surfacing features are useful for adding features to the part. These surface-creating techniques are very specific to the design intent and have been developed keeping the same in mind.

You can use the following advanced blend options to create surfaces: Blend Section To Surfaces — Create a quilt as a blend from a section to

tangent surfaces. The defining parameters here are a section at one end and a surface at the other end, and the resulting geometry is tangent.

Blend Between Surfaces — Create a quilt as a blend from a surface to tangent surfaces. This would typically amount to applying a skin on top of multiple surfaces.

Blend from File — Create a blended surface from a file containing scan point information in the *.ibl format.

Blend Tangent To Surfaces — Create a surface as a blend from an edge/curve to tangent surfaces. The defining parameters here are a curve or edge at one end and a surface at the other end, and the resulting geometry is tangent.

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Blend Section to Surfaces The Blend Section to Surfaces option is used to create a transitional surface

or solid between a set of tangent surfaces and a sketched contour. The set of surfaces selected for the tangent boundary must be closed. Also the section used should be a closed section.

The figure in the slide illustrates an example of creating a transitional surface using the Blend Section to Surfaces option.

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Blend Between Surfaces You can use the Blend Between Surfaces option to create a smooth surface

or a solid transition between two surfaces. The surfaces used for this feature must have matching tangency points for

each point on their surfaces. For example, connecting two spheres of different diameters. The surfaces must be inclined toward each other by a minimum angle of 30.

Blend Tangent to Surfaces You can use the Blend Tangent to Surfaces option to create a surface as a

blend from an edge/curve to tangent surfaces. This option is useful when creating drafts to parts where rounds have been

added to the edges. The draft feature usually fails in such cases. It is also useful when creating joining surfaces between sets of surfaces with

complex shapes.

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Exercise 1: Creating Boundary Surfaces on the ShaverObjectivesAfter successfully completing this exercise, you will be able to:

Create surfaces using curves as boundaries. Modify boundary conditions of surfaces.

ScenarioYou continue to work on designing the Shaver model. You created the design framework required to develop the Shaver body. You create boundary surfaces to develop the Shaver body.

Task 1. Open the Shaver assembly.

1. In the Folder Browser , browse to the module_05\shaver folder. 2. Click on the shaver folder to view the contents of the folder in the browser.

o Right-click the shaver folder and select Set Working Directory.

3. Select the SHAVER.ASM from the browser to preview the model, and then click Open in Pro/E .

4. Turn off the display of all datum features if necessary.

Shaver Assembly

5. In the model tree, right-click BODY_MASTER.PRT and select Open. 6. In the model tree, press CTRL and select Copy 1, Copy 2, PARTING_PROFILE,

Extrude 1, and PROJ_PROFILE. o Right-click and select Hide.

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Hiding Features

Task 2. Create the first surface from boundaries on the top section.

1. Start the Boundary Blend Tool from the feature toolbar.o Press CTRL and select the upper and lower curves, as shown in the

following figure.

Selecting Two Curves in the First Direction

2. Zoom in on the right side of the model.

When creating surfaces from boundaries, always select edges of surfaces (as opposed to

curves) as boundaries whenever possible. This enables you to set up boundary conditions to

adjacent surfaces.

3. Right-click and select Second Direction Curves. o Refer to the following figure, and select an edge to start the chain

selection. o Press SHIFT and select again to highlight the tangent chain, as shown

in the following figure on the left. o Press SHIFT and drag the lower handle to snap to the middle vertex, as

shown in the following figure on the right.

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Selecting the First Curve in the Second

Direction

4. Zoom in on the left side of the model. 5. Select the second curve, as shown in the following figure.

o Referring to the following figure, press CTRL and select an edge to start the chain selection.

o Press SHIFT and select again to highlight the tangent chain, as shown in the following figure on the left.

o Press SHIFT and drag the right handle to snap to the middle vertex, as shown in the following figure on the right.

Selecting the Second Curve in the

Second Direction

6. Select the Curves tab in the dashboard.

o You find two chains each, in the first and second direction. o Cursor over each chain and notice the corresponding curve chain

highlights on the screen. 8. Click Complete Feature .

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Completed Boundary Blended Surface

Task 3. Edit boundary conditions for the boundary surface.

1. In the model tree, right-click Boundary Blend 1 and select Edit Definition. o Notice the surface has four boundaries: top, bottom, left, and right. o Right-click the circular handle on the upper boundary, and select

Normal. o Right-click the circular handle on the right boundary, and select

Tangent. o Right-click the circular handle on the left boundary, and select

Tangent.

Editing Boundary Conditions

2. Select the Constraints tab. Select each of the four boundaries and observe

the references listed for each. 3. Click Complete Feature .

The design intent requires the surface to be tangent to the adjacent surfaces on the left and

right, and for mirroring purposes be normal on the upper edge.

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Boundary Blend Surface Redefined

Task 4. Create the second surface from boundaries on the bottom section.

1. In the model tree, select PROJ_CURVE. o Right-click and select Hide.

2. Start the Boundary Blend Tool from the feature toolbar.o Press CTRL and select the upper edge and lower curve, as shown in the

following figure.

Selecting Curves in the First Direction

3. Zoom in on the right side of the model. 4. Right-click and select Second Direction Curves.

o Refer to the following figure and select an edge to start the chain selection.


o Press SHIFT and drag the upper handle to snap to the middle vertex.

Selecting the First Curve in the Second Direction

5. Zoom in on the left side of the model. 6. Select the second curve, as shown in the following figure.

o Referring to the following figure, press CTRL and select an edge to start the chain selection.

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o Press SHIFT and drag the upper handle to snap to the middle vertex.

Selecting the Second Curve in the

Second Direction

7. Select the Curves tab.

o You find two chains each in the first and second direction. o Move your cursor over each of the chains and notice the corresponding

curve chain highlights on the screen. 8. Select the Constraints tab and configure the boundary conditions, as shown

in the following figure.

Configuring the Boundary Conditions

9. Select each of the four boundaries and observe the references listed for

each. 10. Click Complete Feature .

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Completed Boundary Blend Surface

Task 5. Prepare to refine the surface shape by creating datum points and a sketch.

1. Examine the model. Notice that the surface is pointed near the right end, as shown in the following figure.

Examining the Model

2. In the model tree, drag the Insert Indicator directly before Boundary

Blend 1. 3. In the model tree, right-click PROJ_CURVE and select Unhide. 4. Start the Datum Plane Tool from the feature toolbar.

o Select datum plane RIGHT from the model tree. o Type –45 for the offset, as shown in the following figure. o Click OK in the Datum Plane dialog box.

Creating the Datum Plane

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5. Turn on the display of datum planes and points.

6. Start the Datum Point Tool from the feature toolbar.o Press CTRL, and select datum plane DTM2 if necessary. o Select the upper curve to create PNT6, as shown in the following

figure. o Right-click and select New Point. o Press CTRL, select datum plane DTM2 and the middle curve to create

PNT7. o Right-click and select New Point. o Press CTRL, select datum plane DTM2 and the lower curve to create

PNT8. o Click OK in the Datum Point dialog box.

Creating Datum Points

7. Start the Sketch Tool from the feature toolbar.o Select datum plane DTM2 as the sketching plane. o If necessary, select datum plane TOP as the reference plane and Top

for the orientation. o Click Sketch.

8. Click Specify References .o Select datum points PNT6, PNT7, PNT8 as sketching references. o Click Close.

10. Turn off the display of datum planes and points. 11. Sketch, as shown in the following figure.

o Click Spline from the Sketcher toolbar. o Select the three datum point references. o Right-click and select Dimension.

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o To create the two angle dimensions at the ends of the spline, select the spline first, select the end point, select the vertical reference for the angle, and middle-click to place the dimension.

o To create the two end point radius dimensions, select the end point, and middle-click to place the dimension.

o Edit all dimension values as shown.

Sketching a Spline

11. Click Complete Sketch . 12. In the model tree, select DTM2, Datum Point id 485, and Sketch 1.

o Right-click and select Group. o With the group still selected, right-click and select Rename. o Type OFFSET_CURVE as the new name and press ENTER.

13. In the model tree, right-click the Insert Indicator and select Cancel.

o Click Yes to resume all features.

Task 6. Refine the surface shape by adding the previous sketched curve as an intermediate boundary curve.

1. In the model tree, right-click Boundary Blend 1 and select Edit Definition.o Right-click and select Second Direction Curves. o Press CTRL and select the curve you just created to add as a new

boundary. o Press SHIFT and drag the lower handle to trim the curve to the surface

boundary, as shown in the following figure.

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o Click Complete Feature .

Trimming the Curve

The curves were automatically re-sequenced to maintain a numbering flow of 1-2-3 from right

to left. Also, it is not necessary to always drag curve endpoints to trim to vertices. In this

example, the system automatically trims if the whole curve is selected.

2. In the model tree, right-click Boundary Blend 2 and select Edit Definition.o Right-click and select Second Direction Curves. o Press CTRL and select the curve you just created to add as a new

boundary. o Press SHIFT and drag the upper handle to trim the curve to the surface

boundary, as shown in the following figure. o Click Complete Feature .

Trimming the Curve

3. Select anywhere on the model background to de-select all items. 4. In the model tree, press CTRL and select TOP_PROFILE, BOTTOM_PROFILE,

PROJ_CURVE, Group OFFSET_CURVE. o Right-click and select Hide.

5. Click File > Close Window to return to the shaver assembly window. o Examine the updated shaver assembly.

Some curves will be visible in the Skeleton model.

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Updated Shaver Assembly

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

This completes the exercise.

Exercise 2: Creating Surfaces on the Air Filter Cover (Challenge)ObjectivesAfter successfully completing this exercise, you will be able to:

Create blending surfaces using curve network.

ScenarioYou are continuing with the task of designing the air filter cover for the gas powered drill. The Engineering team has already created several mechanical parts such as the engine and carburetor. You need to create a set of surfaces for the air filter cover part using the references provided.

Task 1. Locate and open the Air Filter Cover.

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1. In the Folder Browser , browse to the module_05 folder. 2. Click the module_05 folder to view the contents of the folder in the browser.

o Right-click the module_05 folder and select Set Working Directory. o Select the AIR_FILTER_COVER.PRT from the browser to preview the

model, and then click Open in Pro/E . 3. Review the sets of curves available in the model that you will use to create

the surfaces.

Available Curve Network

and Points

Task 2. Create a boundary blend surface.

1. Click Saved View List and select AIR_FILTER1. o Turn off the display of all datum features.

2. Start the Boundary Blend Tool from the feature toolbar. o For the boundaries in the first direction, you will select five curve

chains in the following steps.3. Select the first curve chain, as shown in the following figure.

o Select an edge segment in the desired chain. o Press SHIFT and select an adjacent segment to select the tangent

chain, as shown in the following figure.

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Selecting Tangent Chain as First Chain

4. Select the second curve chain, as shown in the following figure.

o Press CTRL and select the curve segment shown in the following figure.

Selecting the first segment in the

Second Curve Chain

5. Press SHIFT and select the previous curve again to start the one-by-one

selection. o Press SHIFT and select the remaining curve segments, as shown in the

following figure.

Second Curve Chain Selected

Since each segment is an individual curve feature, they must be selected as a one-by-one

chain. This could be avoided by selecting the one-by-one chain and copying and pasting it into

a single composite curve before the creation of the boundary surface.

6. Repeat the same procedure to select the third curve chain, as shown in the following figure.

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o Press CTRL and select a segment of the curve. o Press SHIFT and select the previous curve segment again. o Press SHIFT and select the remaining curve segments, as shown in the

following figure.

Selecting the Third Curve Chain

7. Repeat the same procedure to select the fourth curve chain, as shown in the

following figure. o Press CTRL and select a segment of the curve. o Press SHIFT and select the previous curve segment again. o Press SHIFT and select the remaining curve segments, as shown in the

following figure.

Selecting the Fourth Curve Chain

8. Select the fifth curve chain, as shown in the following figure.

o Press CTRL and select a curve segment. o Press SHIFT and select another segment to select the tangent chain, as

shown in the following figure.

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First Direction Curves

9. Continue selecting the curves for the second direction.

o Right-click on the screen and select Second Direction Curves. o Press CTRL and select the three curve chains, as shown in the following

figure.

Defining the Second

Direction Curves

The sequence of selecting the curves for a particular direction is critical for building the

surface.

Task 3. Add tangency constraints to the blended surface.

1. In the dashboard, select the Constraints tab.

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2. Select the Direction 1 – First Chain boundary and select Tangent from the condition drop-down list.

o Notice that the adjacent surfaces are automatically selected as references in the entities list.

3. Select the Direction 1 – Last Chain boundary and select Tangent from the condition drop-down list.

o Notice that the adjacent surfaces are automatically selected as references in the entities list.

4. Click Complete Feature .

Blended Surface

Task 4. Review the surface geometry.

1. Examine the surface model. o Rotate the model and notice the deformation in the surface toward the

top of the model, in the region indicated by the arrows.

We will explore Pro/ENGINEER's sophisticated surface analysis tools later in the course.

Deformation in the Surface

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Task 5. Refine the shape of the curves to refine the resulting blended surface.

1. In the model tree select Curve id 415. o Right-click and select Edit Definition. o Notice that the curve was created using the Thru Points option. o Double-click Tweak in the dialog box.

2. In the Modify Curve dialog box: o Expand the Diagnostics panel.

o Select Curvature and click Show/Hide to show the display of curvature.

o Click Saved View List and select TOP. o Zoom in and drag the control points to match the curvature plots


Refining the Shape of the

Curve

3. Click Complete Feature and click OK. 4. In the model tree select Curve id 418, then right-click and select Edit

Definition. o Double-click Tweak. o Expand the Diagnostics tab.

o Select Curvature and click Show/Hide to show the display of curvature.

o Orient the model to the TOP saved view if necessary. o Zoom in and drag the control points to the match the curvature plots


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Refining the Shape of the Curve

5. Click Complete Feature and click OK. 6. Review the blended surface created.

Modified Blended Surface

7. Click Save from the main toolbar and click OK. 8. Click File > Erase > Current > OK.


Exercise 3: Adding Control Points to the Air Filter Cover (Challenge)ObjectivesAfter successfully completing this exercise, you will be able to:

Define control points in boundary blended surfaces.

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ScenarioYou are continuing with the task of designing the Air Filter Cover for a gas powered drill. You must clean up the set of surfaces created earlier.

Task 1. Locate and open the Air Filter Cover.

1. In the Folder Browser , browse to the module_05 folder and view its contents.

2. Select the AIR_FILTER_COVER_BLEND_CONTROL.PRT from the browser to preview the model, and then click Open in Pro/E .

3. Select Surface id 451 in the model tree. o Notice the number of surface patches in the boundary blend surface.

Boundary Blend Patches

Task 2. Add Control points to the boundary blend surface.

1. Select a sequence of points along the left side of the model. o Right-click Surface id 451 in the model tree and select Edit

Definition. o In the dashboard, select the Control Points tab. o Click on the first Undefined chain in the list. o From top to bottom, select the sequence of five vertices, as shown in

the following figure.

Pro/ENGINEER automatically highlights the next curve available for picking the point.

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Selecting the First Point

Sequence

2. Repeat the above procedure to select a sequence of five points along the

right side of the model.

Selecting the Second Point Sequence

3. Select Second for direction in the Control Point tab of the dashboard.

o Add control points by selecting the vertices, as shown in the following figures.

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Adding Control Points in

the Second Direction


o Notice that multiple patches that were present in the geometry have been replaced by a single set of patches.

Patches Removed using

Natural Fit

Task 3. Change the option of adding the Control points.

1. Right-click Surface id 451 in the model tree and select Edit Definition. o In the dashboard, select the Control Points tab. o Change the Fit option from Natural to Piece to Piece.

2. Click Complete Feature . o Notice the change in the surface structure.

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The option of picking points is not available with this type of parameterization (fit) and

Pro/ENGINEER automatically matches the pieces of the chain with the number of components.

Resulting Blended Surface

Pro/ENGINEER automatically re-parameterizes the curves that define the surface in order to

create a smooth set of surfaces. This option is useful when you want to quickly generate

smooth surfaces. The control available with the manual method of adding control points is not

available in this option.

3. Click Save from the main toolbar and click OK. 4. Click File > Erase > Current > Yes.


Exercise 4: Creating Draft Surfaces (Challenge)ObjectivesAfter successfully completing this exercise, you will be able to:

Create a surface by using the Blend Tangent to Surface option.

ScenarioYou have created an engineering part which has a boss and a few ribs as features. You have gone ahead and added round features on the edges of the part. You

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realize that you have forgotten to add a draft feature on the boss and ribs. Do this without deleting the round features that you have already created.

Task 1. Locate and open the Draft part.

1. In the Folder Browser , browse to the module_05 folder and view its contents.

2. Open the DRAFT.PRT. o Notice the boss and three ribs in the model, as highlighted in the

following figure.

Boss and Ribs Features

Task 2. Define the drafted surface edges.

1. Create a curve defining the edge of the draft for the boss.

o Start the Sketch Tool from the feature toolbar. o Select the surface where the boss begins as the sketching plane, as


Selecting the Sketching Plane

2. Click Sketch.

o Click Concentric Circle from the Sketcher toolbar. o Select the circular edge of the boss and sketch a circle, as shown in the

following figure. o Create a vertical dimension of 2.0 from the circle to the base of the

boss.

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Sketching the Curve

3. Click Complete Sketch from the Sketcher toolbar. 4. Create another set of curves defining the edge of the draft for the ribs.

o Start the Sketch Tool from the feature toolbar. o Click Use Previous.

5. Click Entity Offset from Edge from the Sketcher toolbar. o Select Chain in the Type dialog box. o Zoom in to the right rib on the boss. o Select the first edge and last edge of the rib to define a chain

selection. o If necessary, select Next to highlight the correct chain.

Selecting Tangent Chain

6. Click Accept.

o Type – 2.0 as the value to offset the curve toward the outside, as shown in the following figure.

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Offsetting the Edges of the Rib

7. Click Complete Sketch from the Sketcher toolbar. 8. With the sketch still selected, right-click and select Pattern.

o Notice the default of Reference Pattern and click Complete Feature.

Pattern of Curves for the Ribs

Task 3. Create the draft surfaces for the boss.

1. Click Insert > Advanced > Blend Tangent to Surfaces. o In the Tangent Surface dialog box, select the Create Curve Driven

Tangent Draft graphic icon for the basic option. o Select One Sided for the direction. o Select the surface where the boss starts as the reference, as shown in

the following figure. o Click Okay.

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Selecting the Direction Reference

2. Select the References tab.

o Select Curve Chain from the menu manager and select the offset curve for the boss, as shown in the following figure.

Selecting the Curve Chain for the

Boss

3. Click Select All and click Done to complete selecting the curve chain.

o Verify that the Tangent To collector is set to Automatic. o Click Complete Feature .

In cases where multiple possible tangent surfaces exist, you can manually select the desired

surface. In this case, the system automatically found the top of the boss.

First Blend Tangent to Surface

Task 4. Create the draft surfaces for the ribs.

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1. Click Insert > Advanced > Blend Tangent to Surfaces. o In the Tangent Surface dialog box, select the Create Curve Driven

Tangent Draft graphic icon for the basic option. o Select One Sided for the Direction. o Select the surface where the rib starts as the reference, as shown in

the following figure. o Click Okay.

Selecting the Direction Reference

2. Select the References tab.

o Select Curve Chain from the menu manager. o Select one set of curves defined for the draft surface of the rib, as

shown in the following figure. o Click Select All and click Done to complete selecting the curve chain.

Selecting the Curve Chain for the Rib


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Blend Tangent to Surface at One

Rib

4. With the surface still selected, right-click and select Pattern.


Blend Tangent to Surface at Other Ribs

Task 5. Merge the surfaces with the part.

Remember that the drafts that are created are non-solid surfaces at this point.

1. Select the blended surface on the boss, as shown in the following figure.

Selecting the Blended Surface on the Boss

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2. Click Edit > Solidify.

o In the dashboard, click Solid and Complete Feature .

3. Select the blended surface on the first rib, as shown in the following figure.

Selecting the Blended

Surface on the Rib

4. Click Edit > Solidify.

o In the dashboard, click Solid and Complete Feature .

Solidifying the Rib Blended Surface

5. With Solidify 2 still selected, right-click and select Pattern.


Completed Part with Drafts

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If the offset curve and blended surface for the rib were grouped with the original rib, you can

create a pattern to save time.

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


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

Describe boundary surfaces. Describe types of boundary surfaces. Create a surface with boundaries. Apply constraints at the boundary edges of surfaces. Create blending surfaces using Blend tools.

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Download - ProE Surfacing - Module 5

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