Student Notes: Lesson 4: Surface Re-limitation and Connectionyvonet.florent.free.fr/SERVEUR/COURS...

Student Notes:

CATIA V5 Surface Design- Lesson 4: Surface Re-limitation and Connection��

Copyright DASSAULT SYSTEMES 4-1

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In this lesson you will learn how to limit the surfaces and formconnection between the surfaces.

Lesson 4: Surface Re-limitation and Connection

Case Study: Surface Re-limitation and ConnectionDesign IntentStages in the ProcessRe-limit the SurfacesConnect the Surfaces SmoothlyAssemble the Surface

Lesson contents:

Duration: Approximately 4 Hours

$Speech:

Objectives of the lesson:

- Show tools available to delimit the surfaces (delimit means: extend the surfaces to a limit or reduce the size of the surfaces)

- Show tools available to connect smoothly 2 surfaces (fillet and blend surfaces)

- Show how 2 distinct surfaces can be assembled, creating a single topology%

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Case Study: Surface Relimitation and Connection

The case study for this lesson is ‘Mobile Phone’. The focus of this case study is to use the relimitation and connection tools of Generative shape design workbench, and to dress up the model to achieve the final finished shape.You will be provided with the base surface. While you perform the operations, you will understand the different functionalities of the tools.

$Speech:

The objectives of this case study you will practice at the end of the lesson will enable you to manipulate the tools seen in the lesson.%

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Design Intent

� Cerate a smooth blended edge at the top edge which varies with respect to thickness of the phone.

• Use the Variable fillet to achieve the varying blend along the edge.

� Create a feature groove on the top face of the phone to beautify it or to make it look attractive.

• Trim the tube surface lying on the face to get a groove feature.

� Create a display screen with the flange at inside to mount the display card.

• Trim the top face of the phone at display location using the extruded surface, and keep the inner side of the surface which forms the flange.

� Create key pad holes on the top face of the phone to incorporate number keys.

• Create the key pad profiles in a sketch and project them on the surface. Split the surface using projected curves.

� Create a smooth blended edge on the lower case of the phone.

• Create a blend surface.

The design intent is to create the finished part using the base surface. The model should meet the following given design intents.

A. Top-edge Variable blend

B. Feature Grooves

C. Display Screen

D. Key Pad holes

E. Bottom edge blend

C

B

A

D

E

$Speech:

Discuss the Design Intent of the case study.

Tell the students to perform the case study, you will learn some concepts and tools and use them to perform the case study and other exercises%

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Stages in the Process

The following steps are to be used to perform the case study:

1. Access the Generative Shape Design workbench

2. Scan the model for a better understanding of the modeling sequence.

3. Create Geometrical Sets.

4. Group the features.

$Speech:

To be able to perform the case study successfully we will learn some tools of Generative shape design workbench%

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Step 1: Re-limit the Surfaces

In this section you will learn about different tools to re-limit surfaces.

Use the following steps :

1. Relimit the Surfaces2. Connect the Surfaces Smoothly3. Assemble the Surfaces

$Speech:

Objectives of the step:

-Explain the tools that can reduce the size of a surface

-Explain how a surface can be extended to fit to another surface%

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Why to Re-limit Surfaces

Basic surface geometry, designed, consists of raw surfaces and construction elements. These wireframes and surfaces do not define the final shape.

Operations such as Split and Trim help to convert these raw surfaces into finished geometry.

Surfaces in raw stage

Operations are performed on these raw surfaces to get the finished surface

A. Operations are used to produce the finished geometry shape.

B. Elements involved in an operation are kept in the history of the operation, but are hidden.

While performing operations, keep in mind the following key points:

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Common Tools to Re-limit Surfaces and Curves

Modification of surface limits can be done in two ways:1. By reducing the surface limits 2. By extending the surface limits

Extends surface boundaries with desired continuity.

ExtrapolateExtend surface limits

Trims surfaces involved in the operation with respect to one another.

Trim

Splits one surface with other surface. Only one surface gets affected.

SplitReduce surface limits

IllustrationDescriptionIconNameCategory

$Speech:

Introduce these tools to the students

In Split illustration: The disc is to be split using the cylinder. Observe that in split operation only “The element to be split” gets affected while the splitting or cutting element remains as it is.

In trim illustration: Both the Disc and Cylinder are getting trimmed with respect to each other.

Extrapolate: extending operation%

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Split

Cutting elements

Element to be cut

Cutting elements

Element to be cut A

B

Use the Split tool to remove unwanted portions of wireframe and surface elements.

You can split :

A. Wireframe elements. Wireframe elements can be split by points, other wireframe elements, or surfaces

B. Surfaces. Surfaces can be split by wireframe elements or other surfaces.

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Splitting Elements (1/2)

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3b2

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3a

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3c

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Use the following steps to split an element:

1. Select the Split icon.2. Select the element to cut.3. If necessary:

a. Select additional elements to cut by selecting the bag icon.

b. Select the additional elements.c. Select ‘Close’ to close the Elements to

cut dialog box.4. Select the cutting element(s).5. If necessary, select additional cutting

elements. (Note: we have not selected this additional cutting element.)

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Splitting Elements (2/2)

Use the following steps to split an element:

6. Click on preview7. If you are not satisfied with the side

which is cut, click on Other side to cut another side of the element.

8. Click OK to complete splitting of a surface.

6

7

Note: The cutting element is hidden

8

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Trim

The Trim tool is used to trim two intersecting elements and keep only a part of those elements.You can trim:

A. Two wireframe elementsB. Two surfaces

A

B

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Trimming Elements

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Use the following steps to trim elements:

1. Select the Trim icon.2. Select the elements to be trimmed. Select

the element on the part which you want to retain.

3. If required, change the side to be kept by selecting the ‘Other side’ of element buttons.

4. Click OK to perform the trim operation. The trimmed element is added to the specification tree.

A

B

C

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Difference Between a Split and a Trim

Splitting geometry is breaking all the geometries at the intersection with the cutting element and then removing the unwanted portion. During splitting operation cutting element does not get affected.

Trimming geometry is cutting all the geometries with respect to one another to get the desired shape during trimming operation.

Element to Split

Cutting Element

Select the Side to keep Result of Split operation

Element to be Trimmed Select the Side to keep

Select the Side to keep

Result of Trim operation

Show the split and trim(L4.CATPart/SPLIT_TRIM)

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Why We Need to Extrapolate Elements

Extrap

olated

length

= 65 m

m

The Extrapolate tool is used to extend a surface or a curve. It is often used to extend an element past another so that later these elements can be trimmed, split, or intersected together.

A. Any type of curve or lineB. Any type of surface.

A. Giving a lengthB. Limiting upto an element (Curve or Surface)

A. Extrapolated element as a separate elementB. Extrapolated element assembled with the parent entity

You can extrapolate :

Extrapolation can be limited by:

You can obtain the result:

L= 25mm

Extrapolate upto surface

Show the extrapolation(L4.CATPart/EXTRAPOLATE)

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Extrapolating Elements (1/2)

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3

2

Use the following steps to extrapolate an element:

1. Select the Extrapolate icon.2. For a surface, select the edge

representing the boundary to be extrapolated. For a curve, select the end point of the curve.

3. Select the surface or curve to be extrapolated.

4. Enter the length value. A preview of the extrapolated surface is shown.

3

2

4

Extrapolated Surface

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Extrapolating Elements (2/2)

You will now learn to set propagation mode and continuity type (continued…):

5. Select the Propagation modea. None (Default mode)b. Tangent continuityc. Point continuity

6

5a 5b

6. Change the continuity type to curvature

5c

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Exercise 4ARecap Exercise

20 min

By the end of this exercise you will be able to understand the difference between Split and Trim operations.

In this exercise you will practice Splitting and Trimming operations. You will understand the difference between Trimming and Splitting by performing different instances of operations provided in the different geometrical sets. Detailed instructions for this exercise are provided.

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Exercise 4A (1/2)

1. Open the part. � Open an existing part file. The file consists of

Surfaces and wireframes in different geometrical sets. a. Browse and open part:

Exercise_4A_Start.CATPart

2. Split two surfaces using a third surface.a. Keep one side of the blue surface.b. Keep both side of the Green surface.

End Result

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Exercise 4A (2/2)

3. Split a curve using the following cutting elements.a. Blue curve with Cyan curve b. Green curve with Pink point c. Brown curve with Planed. Pink curve with surface

4. Trim the given three surfaces in one operation.1. Select Green and Blue surface2. Use Other side option to get correct side3. Select Brown surface. Use the Other side option to

get the required side

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Exercise 4A: Recap

� Split and Trim operations on surfaces and wireframe elements.

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Exercise 4BRecap Exercise

20 min

By the end of this exercise you will be able to understand the difference between Split and Trim operations.

In this exercise, you will perform Trim and Split operations on a computer mouse model. You will perform these Split and Trim operations on the same set of surfaces to understand the differences in the operation. High-level instructions for this exercise are provided.

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Exercise 4B

1. Open the part. � Open an existing part file. The file consists of surfaces of

the model of the mouse. Browse and open the part: Exercise_4B_Start.CATPart

2. Split the intersecting surfaces to get the finished shape.� Split the Green and Blue surfaces one by one.� Join the resulting surface� Split between Pink and Joint surface.

3. Perform Trim operation on the same set of parent surfaces.� Trim between Green and Blue surfaces. The resultant

surface would be a single entity.( Unhide the parent surfaces).

� Split the resulting surface with the Pink surface to get the final model.

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Exercise 4B: Recap

� Split and Trim operations on surfaces and wireframe elements.

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Step 2: Connect the Surfaces Smoothly

In this section you will learn about different methods to connect surfaces smoothly.

Use the following steps:

1. Relimit the Surfaces

2. Connect the Surfaces Smoothly

3. Assemble the Surfaces

$Speech:


- See two methods to connect surfaces: fillet (radius) and blends (tension)

- Give you the keys to choose between these 2 methods%

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Why we need to Connect Surfaces Smoothly?

A. Surfaces are closely related to the aesthetics of the product. The reflection of light from the surface should show a smooth variation. If a surface does not own certain described characteristics, visual appearance of the product will get affected.

B. The surfaces should not only be smooth, but also be machinable. Surfaces may have small gaps, ridges which may not be noticeable on the computer screen. If the cutting tool catches on a small ridge or even the tiniest discontinuity, then it can tear a hole in the part which is being machined. When the machine tool tries to drop its cutter into the gap, it gouges a hole.

A

B

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How to Connect Two Surfaces Smoothly?

A

B

You can connect two existing surfaces smoothly using various types of ‘Blends’. The transition of these ‘Blends’, from one surface to another, is smooth as if this blend flows from one surface into another.

These blends are of the following types:

A. Radius Driven Blends - FilletsB. Tension Driven Blends - Blend

Radius Driven Blends Tension Driven Blends

Radius Free Shape

$Speech:

Two ways of connecting surfaces: you can connect surfaces using fillets and in this case, the shape of the connecting surface is driven by a radius. Concretely, a fillet is calculated as if a ball was rolling between two intersecting surfaces (Draw on the board if necessary). Why ? AS we have seen before, a tool can be considered as a sphere. SO, connecting surfaces by rolling a ball on the edges ensures that the part will be “machinable”.

NOTE: even if we’re talking here of connection between surfaces, fillets can also be used to remove sharp edges on already connected surfaces

When you connect 2 surfaces using the blend tool, the connection shape is driven by tensions. The shape is no circular, its evolution is more free.%

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Various Types of FilletsThe following table lists the different types of fillets in GSD workbench

The Chordal Fillet tool creates a fillet on selected edges taking the chord length as the input.

Chordal Fillet

A TriTangent fillet creates a transitional surface by removing one of the three selected surfaces. The fillet surface is created tangent to the three selected faces.

The Face-Face fillet is used when there is no intersection between the selected faces or when there are more than two sharp edges between the faces.

The Variable Radius Fillet tool creates a fillet on a selected edge whose radius varies at a selected point.

The Edge Fillet tool creates a transitional surface along a sharp edge of a surface

The Shape Fillet tool creates a smooth connection surface between two separated surfaces

Description

Shape Fillet

Face-Face Fillet

Tritangent Fillet

Variable Fillet

Edge Fillet

IllustrationIconFillet

Show the fillet and blend(L4.CATPart/FILLETS and BLENDS)

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Creating a Shape Fillet

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Shape fillets are used to create a fillet between two surfaces. You have a choice to select the direction in which the fillet should appear.

Use the following steps to create a Bi-Tangent shape fillet:

1. Select the Fillet icon.2. Select the two surfaces/faces.3. Enter the radius value.4. Ensure that the red arrows point towards the concave

side of the fillet. If not, select on the arrow to change its direction.

5. Specify the Extremities conditions.6. Clear the Trim Support options if you do not want to have

the supporting elements assembled into the fillet feature.7. Click OK to create the shape fillet.

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Shape Fillet Extremities Management

DC

BA

Creating fillets using surfaces gives greater control to the resulting element.

For example, the connection between the fillet and the support surface(s) can be customized to create the desired geometry.

There are four options to control the extremities of a fillet:

A. The Smooth filletB. The Straight filletC. The Maximum filletD. The Minimum fillet

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Creating an Edge Fillet

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5

Edge fillets are used to create a fillet on the sharp edge of a surface.

Use the following steps to create an edge fillet:

1. Select the Fillet icon.2. Select the sharp edges to smooth.3. Enter the radius value.4. Choose the propagation mode:

• Tangency• Minimal• Intersection edges

5. Validate by clicking OK.

2

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Edge Fillet: Blending Vertex (1/2)

Edges to fillet

If the initial geometry is modified, the fillet sequence cannot be recalculated:

When the initial geometry with sequence of fillets is modified, the sequence of fillets may fail and the designer may have to have a new fillet sequence:

The Blend Vertex allows you to make fillets that are more stable during the modifications.

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Edge Fillet: Blending Vertex (2/2)

3

1. Select the Fillet icon.2. Select the edges on which you want to

make fillets.3. Click on the “More” button to expand the

fillet dialog box:4. Click on the “Blend Corner” button:5. Specify the setback distances and confirm

the fillet creation by clicking OK.

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Edge Fillet : Keeping Edges

In some case, you may need to indicate that an edge should not be filleted, if a radius is too large for instance.

Click on the more button to expand the dialog box, then select the edge you want to retain.

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Creating a Chordal Fillet

Chordal fillets are used to control the width of the fillet fromend to end, especially when the fillet is performed after the Variable Draft operation.

Use the following steps to create a Chordal fillet:

1. Select the Chordal Fillet icon.2. Select the edges to be filleted.3. Specify the Chord length (If required you can specify

variable chord length).4. Click OK. The Chordal fillet is generated.

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Creating a Blend (1/3)

Blend is a surface that is created between two support surfaces forming a smooth transition between them.You can create a blend of point, tangency and curvature continuity. Further you can control the shape of the surface by applying different tension values.

Use the following steps to create a blended surface: 1

1. Select the Blend icon.2. Select First curve and support.3. Select Second curve and support.4. Select the type of continuity you want between

surfaces. Here Tangency is selected.5. Click OK to create the blend

1st Curve1st Support

2nd Curve2nd Support

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7

Now you will learn how to change the continuity type of the blend.

6. If the supports are specified, define the type of continuity (Point, Tangency, Curvature) for each side.

7. If required, select the Trim Support options. When selected, the support surfaces are trimmed and are assembled into the blended surface.

Connected with Point Continuity

Connected with Tangent Continuity

Connected with Curvature Continuity

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8

Default tension

Constant tension of 2.5

Linear tension from 1 to 2.5

Use the following steps to change the tension values in the blend to modify its shape

8. Specify tension at the blend surface limits. Tension can be specified as:a. Defaultb. Constantc. Lineard. S type

9. Click OK to generate the blend surface.

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Criteria for Selecting Blends and Fillets

There are several types of blends and the choice depends on the functional requirements as well as on the desired aesthetic look of the part.Fillets are used for mechanically connecting surfaces with tangency continuity. Blends are used to create a surface of flexible shape controlled by tension. Thus blended surfaces are mainly used to give a good shape to the product.

Surfaces Continuity

Curvature Evolution

Curvature (G2)

Tangency (G1)

No Continuity Point Continuity

Fillet

Blend

Manufacturing requirements

Visual requirements

Compare the junction with fillets and the connection with blends (L4.CATPart/BLEND vs FILLET)

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Step 3: Assemble the Surfaces

In this section you will learn how to assemble various surfaces.

Use the following steps:

1. Relimit the Surfaces2. Connect the Surfaces

Smoothly

3. Assemble the Surfaces

$Speech:


-Explain the tools available to assemble surfaces (or curves)%

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Why to Join Elements?

1. There is only one feature to be selected in the Tree.

2. Some CATIA tools require only one element as input, in such cases Join can be selected.

Join operation is used when you want to concatenate or logically group adjacent surfaces/wireframes into a single element that can be used for future operations.

It is a mechanical assembly of curves or surfaces which forms a single entity in the tree.

Advantages:

1

2

3

Bottle Top

Bottle Body Bottle BottomShow the join(L4.CATPart/JOIN)

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Joining Elements

1

2

Use the following steps to join elements:

1. Select the Join icon.2. Select the elements to be joined.3. Click OK to complete the operation.

2a

2b2c

3

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Joining Elements – Exclude Sub-Elements

While joining the elements, you can exclude some sub-elements from the joined surface.Use the following steps to exclude sub-elements:

1. Select the elements to be joined or edit the existing Join operation.

2. Select the elements you want to exclude from the joined surface through the Sub-Elements To Remove tab.

3. Click Preview to create the join4. If you want to create a separate join of the excluded

elements, select Create join with sub-elements option. Observe that one more join node is added in the tree

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Checks While Joining Elements Together (1/3)

You will learn about various options in Join that enable you to confirm whether the surfaces under consideration are connected as desired.

A. Check Connexity: When this option is selected, the Join operation will be performed only if the elements to be joined are connected or when the gap between the surfaces is within permissible limits.Surfaces cannot be joined when :

Solution

Non-Connex Result counts two domains:When the gap between the surfaces is more than the Merging Distance(permissible value). Here a gap of 0.07 mm already exists between the surfaces.

Non-Connex Result counts two domains:When the surfaces to be joined intersect each other (which results in the formation of separate domains)

Error DescriptionIllustration

Split the surfaces with each other

Remove the Gap or enter Merging distance value greater than 0.07mm

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B. Check Tangency: When this option is checked, the Join operation will be performed only if the elements to be joined are continuous in tangency or when the discontinuity is below defined threshold value.

SolutionError DescriptionIllustration

An Error message is prompted when the surfaces to be joined are discontinuous in tangency. Here a tangency discontinuity of 0.7 deg exists between these surfaces.

Modify the geometry by making it tangent or set the Angular Threshold value greater than 0.7 degrees.

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C. Check Manifold: This option is active only for curves. This option when checked, forbids creation of non manifold configurations. A wireframe element is called “manifold” when at least one of its vertex points join at least 3 edges.

1 Vertex point

3 Edges

D. Simplify the Result: This option reduces the number of cells in the resulting elements.

1

2

1

2

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Why Federate the Join? (1/2)

A- Surfaces are made of several faces.Elements created from a surface are in fact created from its faces.

B- A modification of the part geometry may lead to a change in the supporting face.

The pad has been created with the option “Up to surface”, using the blue surface.A fillet have been added to the top edge of this pad.This edge depends on the face of the blue surface.

The sketch supporting the pad has been modified so that the filleted edge does not lie anymore on the same face

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Why Federate the Join? (2/2)

C- This change can lead to an update error because the elements created from these faces are no longer recognized.

D- Federating the faces of the surfaces, this kind of update error does not occur anymore.

During the update of the part, an update error occurred: The filleted edge is not recognized.

To solve the problem, you have to federate the faces of the blue surface.Then the part is updated without any problem.

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Assemble Result - Geometry Creation Tools (1/2)

Option

When you Trim elements together, by default, the result will always be a single feature in the tree.

By activating ‘Trim elements’ option, curves get assembled and form a single entity in tree. The parent curves go into the hide mode.

By activating ‘Trim elements’ option, curves get assembled and form a single entity in tree. The parent curves go into the hide mode.

IllustrationDescriptionTool

The following table sums up the tools which give assembled output in the specification tree

Option ‘ON’

Option ‘ON’

Option ‘OFF’

1 2

3

1

1

2

3

1

Option ‘OFF’

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Assemble Result - Geometry Creation Tools (2/2)

By checking the ‘Trim Supports’ option, the blend surface is relimited upto the curves. A single feature is created in the tree.

When ‘Assemble result’ option is checked, the Extrapol result gets assembled with the parent feature and forms a single feature in the tree.

By activating the ‘Trim Supports’ option, the surfaces and fillet form a single entity in the tree and the parent surfaces go into the hide mode

IllustrationOptionDescriptionTool

The following table sums up the tools which give assembled output in the specification tree

Option ‘OFF’ Option ‘ON’

Option ‘OFF’ Option ‘ON’

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To Sum Up

In the following slides you will find a summary of the topics covered in this lesson.

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Re-limit the Surfaces

The image shows the difference between Split and Trim. Splitting is breaking all the geometries at the intersection with the cutting element and then removing the unwanted portion. During splitting, cutting element does not get affected.

Operations such as Split and Trim help to convert raw surfaces and construction elements into finished geometry. Elements involved in an operation are kept in the history, but are hidden.

Trimming is cutting all the geometries with respect to one another to get the required shape.

You can connect two existing surfaces smoothly using following ways:

� Radius Driven connections - Fillets� Tension Driven connections - Blend

The choice of the blend depends upon the functional requirement and aesthetics of the part. Fillets are used for mechanically connecting surfaces with tangent continuity. Blend are used to create a curvature (G2) connection between the surfaces and obtain a more aesthetic result.

Connect the Surfaces Smoothly

Result of Split operation

Element to Split

Cutting Element


Element to be Trimmed Select the Side to keep


Result of Trim operation

Radius Driven Blends

Tension Driven Blends

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Assemble the Surfaces

Join operation is used to concatenate or logically group adjacent surfaces / wireframes into a single element that can be used for future operations.

The merging distance is given by a threshold value (similar to smooth tool) this makes Join a tolerant modeling tool (allows the creation of non-continuous features that can be accepted in certain cases).

Bottle Top

Bottle Body

Bottle Bottom

Similarly some other tools which offer the possibility to assemble features on the fly are Connect Curve, Corner, Trim, Fillet, Blend and Extrapolate.

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Main Tools

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Split: Splits one surface with other surface. Only one surface gets affected.

Trim: Trims surfaces involved in the operation with respect to one another.

Extrapolate: Extends surface boundaries with required continuity.

Fillet: Mechanically connects surfaces with tangent continuity.

Join: Logically groups adjacent surfaces or wireframe.

Operations Toolbar

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Exercise 4CRecap Exercise

20 min

In this exercise, you will practice the tools of Generative Shape Design workbench such as Trim, Edge Fillet and Variable Fillet. You will be provided with the Die Surface of an automotive panel. You will use the advanced options of the fillet command to blend the sharp edges. Detailed instructions for this exercise are provided.

By the end of this exercise you will be able to:

� Trim the surfaces as required.

� Blend the sharp edges using edge fillet.

� Apply a variable fillet to the sharp edges.

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Exercise 4C (1/5)

2. Insert a new Geometrical Set and name it as Operations.� Create the Operation features in a new

geometrical set.

3. Trim the surfaces to attain the final shape of the panel.� Trim between the Green and Purple surface.

a. Select Trim Iconb. Select Purple surface c. Select Green surfaced. Keep the surface side requirede. Click OK to attain a final shape


datum surface of Draw Panel.a. Browse and open part:

Exercise_4C_Start.CATPart

3b

3c

3d

3a

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Exercise 4C (2/5)

4. Fillet the top edge of the panel.� Create an edge fillet. Use Blend Corner option to

get a smooth blend at the Vertices.a. Select Edge Fillet Icon.b. Select the edges forming the vertex shown.c. Specify the radius [200mm].d. Select Blend Corners button in to the more

option. Four vertices are selected.e. Specify the Setback distance as [250mm].f. Select Plane.1 as a limiting element for the

fillet.g. Select OK to generate the fillet.

Fillet limited to Plane.14a

4b

4f

4c4d

4e

4g

The edges which form a corner have to beselected manually.

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Exercise 4C (3/5)

5. Fillet the remaining edge of the panel.� Create an edge fillet on the remaining edge of the

panel. a. Select Edge Fillet Icon.b. Select the edges forming the vertex shown.c. Specify the radius [200mm].d. Select Blend Corners button in to the more

option. Two vertices are selected.e. Specify the Setback distance [400mm].f. Select OK to generate the fillet. Vertices to be blended

5a

5b

5c5d

5e

5f

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Exercise 4C (4/5)

6. Trim the surface length.� Trim between the filleted surface and curved

surfaces as shown.a. Select Trim Icon.b. Select the surfaces to be trimmed.c. Keep the surface side required.d. Select OK to Trim the surface.

6a

6b

6d

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Exercise 4C (5/5)

7. Create a Variable fillet at the trimmed edge.� Create a Variable fillet on the remaining edge of

the panel. a. Select Variable Fillet Icon.b. Select all the edges to be filleted.c. Specify the varying radius value on each

edge( varying from 250 to 150mm).d. Select OK to generate the fillet.

7a

7b

7d

7b

200mm150mm

200mm250mm

250mm

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Exercise 4C: Recap

� Trim the surfaces to your needs.

� Blend the sharp edges using an edge fillet.

� Apply a variable fillet to the sharp edges.

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Exercise 4DRecap Exercise

20 min

In this exercise you will practice the Surface Blend and Filleting tool. You will understand the difference between a blended surface and a fillet by analyzing the results. High-Level instructions for this exercise are provided.

By the end of this exercise you will be able to:

� Create a blended surface between two existing surfaces.

� Create a shape fillet between two intersecting surfaces.

� Join two or more surfaces

� Split the surfaces using a curve.

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Exercise 4D (1/6)


extruded surfaces.a. Browse and open part:

Exercise_4D_Start.CATPart

2. Create a Blend surface between two extruded surfaces.� Create a blend using the two sketches.Use the

extruded surfaces as support.

Extruded Surfaces

Sketches

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Exercise 4D (2/6)

3. Create a boundary.� Create a boundary of Extrude.1 surface.

4. Fill the boundary.� Select the Planar Boundary Only check box to fill the

boundary.

BoundaryFill

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Exercise 4D (3/6)

5. Join surfaces.� Join blended surface and the extruded

surfaces.

6. Create a Shape Fillet.� Create a fillet between joint surface and the

filled surface.

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Exercise 4D (4/6)

7. Create Parallel curves.� Hide this fillet and unhide the join and fill

surface from the specification tree. � Create parallel curves on join and fill surface

using a boundary curve (You will be reusing these surfaces to create Blend).

8. Split the surfaces.� Split the fill and join surface using respective

parallel curves.

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Exercise 4D (5/6)

9. Create a blend surface between two split surfaces.� Create a blend between two split surfaces.

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10. Create two join surfaces.� Join all the surfaces which include filleted surface (but not

the blend surface created in step 9).� Join all the surfaces which include blend surface (but not

the filleted surface created in step 6).� Intersect the two joins created with ZX plane. (This

intersection curve will be used for Porcupine analysis in the next step).

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Exercise 4D (6/6)

10. Porcupine analysis results of filleted surface and blend surface.� Filleted surface

a. Surface produced by Fillet tool is tangent continuous surface.b. The shape of the fillet is invariable.c. It is a radius driven shape.

� Blend surface.a. Surface produced by Blend tool can be Point, Tangent or Curvature

continuous surface.b. The shape of the surface is variable.c. It is a tension driven shape.

Filleted surface with tangent continuity Blended surface with Curvature continuity

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Exercise 4D: Recap

� Create a blend surface between two existing surfaces.

� Create a shape fillet between two intersecting surfaces.

� Join two or more surfaces

� Split surfaces using a curve.

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Case Study: Surface Re-limitation and ConnectionRecap Exercise

30 min

Using the techniques you have learned in this lesson, and with tips from the previous exercises, create the model without detailed instruction.

� Create a smooth blended edge at the top, this edge varies with respect to thickness of the phone.

� Create a feature groove on the top face of the phone to add aesthetics.

� Create a display screen with a flange on the inside to mount the display card.

� Create key pad holes on the upper part of the phone for number keys.


In this exercise you will practice how to use the surface Re-limitation and Connection tools.

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Do It Yourself: Surface Re-limitation and Connection (1/4)

1. Open the given part consisting of base surfaces of mobile phone model in the Generative Shape Design Workbench.a. Browse through the files and open the

model Case_Study_Start.Catpartb. Study the part.

2. Trim between the top and the side surfaces a. Trim between the Pink and Blue surfaces.

3. Create a smooth blended edge at the top with respect to thickness of the phone.a. Create a Variable Fillet along the top edge

as shown.b. The radius of the fillet should vary from

0.5mm to 4.0mm. 0.5mm

4.0mm

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4. Create a feature groove on the top face of the phone to add aesthetics.

a. Trim the sweep surface from the top face as shown.

b. Keep the surface to form a groove on the main body.

c. Create the groove at both the locations specified.

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5. Create a display screen with a flange inside.a. Create a trim between the main surface and the

extruded surface as shown.b. Keep the inner portion of the extruded surface to

create a flange like feature.

6. Create a key pad holes on the upper part of the phone for number keys.a. Project the sketch consisting of key profiles on

the main surface. Each profile in a sketch is an output feature.

b. Split the main surface with a projected curve as shown.

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7. Create a smooth blended edge on the lower case of the phone.a. Create two parallel curves. Create one on the

brown surface and another on the green surface at 3mm distance from intersection curve, as shown.

b. Split the surfaces with the parallel curve lying on them.

c. Create a blend surface between two parallel curves.

8. Join the surfaces of lower case and upper case separately.

9. Fill the display screen and apply transparency to the surface.

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Intersection Curve

Parallel Curves

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Case Study: Surface Re-limitation and Connection Recap

� Create a smooth blended edge at the top, the edge varies with respect to thickness of the phone.

� Create a feature groove on the top face of the phone to add aesthetics.

� Create a display screen with a flange on the inside to mount the display card.

� Create key pad holes on the upper part of the phone for number keys.


Student Notes: Lesson 4: Surface Re-limitation and Connectionyvonet.florent.free.fr/SERVEUR/COURS...

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