Student Notes: Surface Modification Toolsyvonet.florent.free.fr/SERVEUR/COURS CATIA/CATIA... · 2012-09-25 · Student Notes: CATIA V5 Automotive - Body Lesson 9: Surface Modification

Student Notes:

CATIA V5 Automotive - Body Lesson 9: Surface Modification Tools��

Copyright DASSAULT SYSTEMES 9-1

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In this lesson, you will learn how to perform operations to modify the surface geometry, how to analyze surfaces and correct defects.

Surface Modification Tools

Lesson Contents:

Case Study: Surface Modification ToolsDesign IntentStages in the ProcessTransform SurfacesAnalysis and Correction

Duration: Approximately 0.5 day

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Case Study: Surface Modification Tools

The case study for this lesson is a simplified outer door used in the door assembly shown below.

The case study focuses on the creation of transformation features, analysis and correction of the surfaces.

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Design Intent

� Window opening (A) of the inner door must be reduced by 10% in X and Z directions.

• Affine the window opening curve using the center of gravity as the origin.

� The lower door surface (B) must be curvature continuous.

• Smooth the parent curves of lower door surface.

� Simplify the model structure.

• Delete the redundant elements in the model.

The model of the simplified outer door must meet the following design intent requirements:

A

B

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Stages in the Process

1. Affine a window curve using the center of gravity as the origin.

2. Replace the window curve by the new affined curve.

3. Check the surface for curvature continuity.

4. Smoothen the section curves of lower door surface.

5. Replace the section curves of the lower door surface with new smooth curves.

6. Delete useless elements.

Use the following steps to create the model of a simplified outer door:

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Transform SurfacesIn this section, you will learn how manipulate the surface geometry to create the final surface model.

Use the following steps to create the simplified outer door :

1. Transform Surfaces2. Analysis and Correction

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A. Affinity is an important operation to resize the part by different amounts in different directions, according to a defined axis system.

B. The Axis-to-Axis transformation is useful when more than one reference axis system and part element must be moved from one axis to another.

Why Are Operations on Geometry Needed?

A

B

Operations such as Extrapolate help to extend the curve or surface.

Transformation operations such as scaling and affinity, help to resize the part.

Transformation operations such as translate and rotate, help to change the positioning of the part in the co-ordinate axis system.

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

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Extrapolating Elements - Introduction

B

AExtrapolations can be limited:

A. Up to element

B. At a specified length

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

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Extrapolating Elements (1/2)

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1. Click 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 extracted.

4. A preview of the extrapolated surface is shown.

Use the following steps to extrapolate an element:

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5. Specify the extrapolation mode. The default extrapolation mode is Length. In this example, the extrude extrapolation type is Up to element.

6. Depending on the extrapolation mode, select element or specify the length.

7. Click OK.

Extrapolating Elements (2/2)

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Use the following steps to extrapolate an element (continued):

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Transformations (1/3)

A

B

A. The Translation tool is used to move a selected element. Translation can be made by specifying a direction and distance, selecting start and end points, or using coordinates.

B. The Rotation tool is used to rotate a selected element about an axis.

Transformations are used to modify the size, location, and orientation of a wireframe or surface element.

The following six transformation types are available:

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C

D

C. The Symmetry tool is used to create the mirror image of the selected element. The element can be mirrored about a point, line, or plane.

D. The Scaling tool is used to resize a selected element. The element is scaled about a selected point, plane, or planar surface using a scaling factor.

The following six transformation types are available (continued):

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E

F

E. The Affinity tool scales the selected element in the X, Y, or Z direction based on a selected axis system.

F. The Axis to Axis tool duplicates and positions the selected geometry based on a new axis system.

The following six transformation types are available (continued):

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Restoring Elements (1/2)

You can restore the limits of the surface or a curve which has been split once or several times.

By restoring the geometry you will get the initial untrimmed elements of the geometry (surface or curve).

Based on the selection, you can untrim the inner, outer and entire face of the surface.

Untrimmed

Untrimmed inner Loops

Untrimmed outer Loops

Untrimmed entire face

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Restoring Elements (2/2)

1. Click the Untrim icon.2. Select the Surfaces or Curves to be

restored.3. Click OK .The initial surface is

automatically restored.

Use the following steps to extract a face from a surface.

Untrimmed

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Access the Invert Orientation from the Menubar - under Insert/Operations.

How to Invert Orientation

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Click OK to confirm. The Invert operation is added to the specification tree.

Select the curve or surface to invert its orientation. The initial display of the red arrow is the already inverted direction.

Clicking on the red arrow or on the Reset Initial button displays the initial (uninverted) orientation of the element.

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Exercise: Update Errors ManagementRecap Exercise

30 min

In this exercise you will practice update error management on B-pillar. High-level instructions for this exercise are provided.

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

� Modify the input of the B-pillar and manage the errors during the update.

� Create necessary corrections.

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Do it Yourself (1/6)

2. Replace the cutting surface in the completed model• Replace ‘SURF2’ available in the geometrical set

‘INPUT_MAIN_SHAPE’ by ‘SURF5’ available in the geometrical set ‘NEW_STYLE_SURFACES’.

• During the update of the part, you get this error message

1. Load Ex9A.CATPart.• Load Ex9A.CATPart. This part already has

some curves and surfaces created for you.

Replace SURF2 with SURF5

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3. Analyze and find the problem area in the model• Hide ‘MAIN_SHAPE’ feature available in the

‘Main_Shape’ geometrical set.• Show ‘EdgeFillet.1’ to visualize the feature.• Hide ‘SURF2’ and ‘SURF5’ surfaces for better

visualization of the problem area.

Observation:You can see that the problem comes from an interruption in the filleted edge.So we have to scan the parents of EdgeFillet.1 to find the source of the problem.

“Ribbon has stopped on slightly sharp edge”

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4. Analyze the Parents/Children relations of the feature• Find the parents of Edge fillet.1 through

Parents/Children dialog box. Show Trim.3. You would not find any problem in Trim.3 surface affecting the edge fillet.

• Find the parents of Trim.3 through the Parents/Children dialog box. Show SURF.9. You will see that SURF9 cannot be the source of this corrupted edge.

SURF 9

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4. Analyze the Parent/Children relations of the feature (continued)• Hide SURF9 and look for the parents of ‘Trim2’.

Show ‘Sweep.3’ and see that it is not the source of the corrupted edge.

Sweep.3

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4. Analyze the Parent/Children relations of the feature (continued)• Hide ‘Sweep.3’ and look for the parents of ‘Trim.1’.• Show SURF8, it is the source of the problem, this

surface is not large enough to create a good intersection, it needs to be extrapolated.

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5. Extend the SURF8 to solve the corrupt edge problem.• Define in work object the ‘INPUT_MAIN_SHAPE’

geometrical set.• In this geometrical set, extrapolate the surface

SURF8.• Replace SURF8 with a new extrapolated surface.• Update the part. The part now gets updated

correctly.• Hide the intermediate surfaces and show the

MAIN_SHAPE

SURF8 surface Extrapolated

Replace SURF8 with a new Extrapolated surface

Surface gets updated with a new styled surface

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Exercise Recap: Update Errors Management

� Modify the input of the B-pillar and manage the errors during the update.

� Create necessary corrections.

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Exercise: Surface SymmetryRecap Exercise

15 min

In this exercise you will finalize the tunnel model using the tools learnt in this step. High-level instructions for this exercise are provided.


� Create a Symmetry of the surfaces

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2. Relimit the main surface to get a final shape• Create a Geometrical Set called ‘Tunnel’.• Create a trim between the surfaces ‘TUNNEL_ONLY’

and ‘ SHOE_ONLY’.• Split the resultant surface using ‘REAR_PANEL’

surface.• Hide the ‘REAR_PANEL’ surface.

1. Load Ex9B.CATPart.• Load Ex9B.CATPart. You will work on the

surfaces provided in this part.

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3. Finalize the Tunnel surface• Symmetry the resultant split surface along the ZX

plane.• Join the two halves to form a complete tunnel.• Apply an edge fillet of radius 10mm on the edge

shown.• Rename the fillet as ‘TUNNEL’.

Edge to fillet

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Exercise Recap: Surface Symmetry

� Create a Symmetry of the surfaces

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Analysis and CorrectionIn this section, you will learn how analyze a curve connections, surface connections and to achieve the required continuities.

Use the following steps to create the simplified outer door :

1. Transform Surfaces2. Analysis and

Correction

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Curvature Analysis

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D

B

A

A. Gaussian: Measures the mean curvature value.

B. Minimum: Measures the minimum curvature value.

C. Maximum: Measures the maximum curvature value.

D. Inflection Area: Identifies the curvature orientation.

E. Limited: Checks if a tool with an end radius can mill the part.

The Curvature Analysis tool is used to create high quality surfaces by detecting faults that may exist in a surface.

The following analysis types are possible with this tool:

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Performing a Surface Curvature Analysis

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1. Click View > Render Style > Customize View. Select the Material option.

2. Click the Curvature Analysis icon.3. Select the surface to be analyzed.4. Select an analysis type. 5. Adjust the color ranges by double-clicking

on the values to be adjusted.

Use the following steps to perform a surfacic curvature analysis:

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Connect CheckerIn this section, you will learn how to analyze curve connections, surface connections and how to achieve the required continuities.

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Curve Connect Checker (1/3)

Curves generated in CATIA V5 are likely to be continuous curves. CATIA provides Tolerant modelingfeatures which can resolve some of the problems that may occur at the time of curve creation.

Continuity check on curves is mostly used for curves imported into CATIA V5.

When a curve is imported into CATIA V5, you may find problems such as the curve is self intersecting, is disjoint, has discontinuities in its tangencyor curvature thus leading to geometrical flaws in the model.

Hence, you should always check the curve for the above mentioned defects and repair the curve before creating surfaces.

Many a times the defect on the curve cannot be seen with the naked eyes. In the Generative Shape Design workbench you have tools to check the continuity of the curves and measure the severity of its defects.

Discontinuous Curves

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If you have imported a curve from another application and you want to know if it is good before creating surfaces on it, you can use the Connect Checker and Porcupine analysis tools to detect the discontinuities.

Connect Checker allows you to detect the Point, Tangency or Curvature discontinuities between two or more curves.

The Connect Checker can detect :

A. The Distance between two or more curveB. The Tangency discontinuities

C. The Curvature discontinuitiesD. An Overlap by highlighting the affected area.

A

B

C

D

In order to have a tangent continuous surface, the wireframe quality criteria must be curvature continuous.

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Use the following steps to check the connection between the curves.

1. Select both the curves to be analyzed.2. Click the Curve Connect Checker icon.3. The Connect Checker dialog box is displayed. You

can choose the type of analysis to be performed using the buttons provided: G0,G1,G2 and G3

4. Select the Quick button.5. Select the desired box to know the results.

a. G0: In this case, distances more than 0.1mm are highlighted.

b. G1: Tangent discontinuities which are more than 0.5 deg are highlighted.

c. G2: Curvature discontinuities which are more than 5% are highlighted.

d. G3: Curvature-Tangency discontinuities which are more than 0.05deg are highlighted.

e. Overlapping option displays the status of overlap between the two curves.

6. Click OK to finish the Curve analysis.

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5b

5c5a

0.08deg0.08deg

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Surface Connect Checker (1/13)

The following table discusses common types of flaws that can be detected between surfaces.

Tangency and Curvature discontinuities

Overlapping Surfaces

Gaps between surfacesSurface continuity faults

IllustrationDescriptionFault Category

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The following table discusses common types of flaws that can be detected between surfaces (continued)

Surface Inflections

Formation of bump in the surface

Sharp variation in the surface boundaries

Irregular surface boundaries

IllustrationDescriptionFault Category

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A. Tool to detect surface connection faults:Connect Checker tool is used to check connections between two or more surfaces. The tool gives a measure of Distance (mm), Tangency (degrees) and Curvature(percentage) between the edges of thesurfaces.

B. Tool to detect irregular surface boundaries:Porcupine Analysis tool is used to detect the imperfections in the boundaries of a surface that is not visible to the naked eye. The resultis shown in the form of spikes.

C. Tool to detect Surface Inflections:Surfacic Curvature analysis is used todetect curvature changes on a surface or group of surfaces.

The following analysis tools give you a visual information in the form of color codes, helping you to differentiate the good areas and the bad areas depending upon the standards set. (Tools to detect geometrical connections)

A

B

C

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You can perform the following types of connection analysis using the Connect Checker tool:

A. Boundarya. Curve-Curveb. Surface-Surface

B. Projectiona. Curve-Curve b. Surface-Surface c. Surface-Curve

In ‘Boundary’ the connection analysis is performed between the boundaries of the elements.In ‘Projection’ the connection analysis is performed between the boundary of one element and projection of that boundary on another element.

Target option is available only for ‘Curve-Curve Connection’ and ‘Surface-Surface Connection’ in the Projection mode.

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The following table describes the capabilities of the connect checker tool

The RED area highlights gaps between 0.5 and Max value

The Yellow area highlights tangency discontinuities between 0.5deg and Max value

The Blue area highlights curvature discontinuities of 200%

The information saying 2 overlaps is detected and displayed

Analysis at the common edge in a single surface is displayed

Quick AnalysisAnalysis Type

Checks overlap between surfaces.

Analysis can be done for surfaces having internal edges (Two joined surfaces)

The curvature (1/R) difference at the connecting edges of surfaces is measured. The curvature difference is measured using a formula and is expressed in percentage. The discontinuity range is between 0 – 200 %. Lesser the percentage value better the surface connection.

The angle between the surfaces at the connection is measured. If the angle is less than 0.5 deg, CATIA surfaces are considered continuous in Tangency.

The distance between the vertices of the surfaces is measured. If the distance is less than 1 micron, CATIA surfaces are considered continuous in point.

Description

Overlap of surfaces

Curvature (G2)

Distance (G0)

Interpretation

Internal Edges

Tangency (G1)

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The Connect Checker allows the user to examine:

a. Distance (G0 continuity) in mmb. Tangency (G1 continuity) in degc. Curvature (G2 continuity) in degd. Curvature-Tangency (G3) in dege. Overlap

The Boundary mode of analysis allows you to perform the analysis between the edges of the surfaces.

G0 analysis G2 analysis

G1 analysis G3 analysis

Connection Analysis in Boundary Mode:

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Use the following steps to perform Quick connection analysis between two surfaces in Boundary mode.

1. Multi-select the two surfaces between which you would like to check the connection.

2. Click the Connect Checker tool.

3. Choose the analysis type: You will perform distance analysis

4. Set the maximum gap to 0.7 mm. This gap represents the maximum permissible gap between the surfaces.

The Quick Analysis displays the Max. actual gap of 0.67mm between surfaces.

5. Define the tolerance range between 0.3mm-0.7 mm. Observe that only areas which have values between this range are highlighted in RED.

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Use the following steps to perform Quick connection analysis between two surfaces in Boundary mode (continued).

6. Switch to Full Analysis mode. The analysis shows the default colorranges and the default tolerance range. Observe that the lower limit is 0.001mm and upper limit is 0.1mm.

6

Lower Limit

Upper Limit

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Use the following steps to perform Quick connection analysis between two surfaces in Boundary mode (continued).

7. Double-click on the values to define new ranges to customize the tolerance range to suit to your requirement i.e. from 0.3mm to 0.7mm.(and not from 0.001mm to 0.1mm).

8. Similarly, re-define all the values for the analysis.

9. Modify the color of the analysis, by right-clicking on that particular color

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The Projection mode for Surface-Surface analysis allows you to directly project the boundary or the edge of the first selected surface onto the second surface. The analysis is then performed between this source border and its projection on the second surface.

Edge or Boundary of the surface Target Surface

Source Surface

The surface selected first is the ‘Source’ surface. The edge or the boundaries of this surface will be projected on the other surface.

Similarly the second surface which is selected is the ‘Target’Surface.

Projection on Target surface

Surface-Surface Connection Analysis:

Connection Analysis in Boundary Mode:

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Surface-Curve Connection Analysis:

The Surface-Curve connection analysis is performed only in the Projection mode. Here connection analysis is done between extremity of a curve and it’s projection on a surface.

Let us understand this with the help of an example:

B (Projection of an extremity of the curve on a surface)

.

A (Extremity of the curve)

.

A

B

Projection of an extremity of the curve vertically

In this case, A is the extremity of the curve, and B is the orthogonal projection of A on a surface. The connection analysis will show the discontinuity values between them.

Projection of an extremity of the curve horizontally

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Use the following steps to perform Quick connection analysis between two surfaces in Projection mode:

1. Select the Connect Checker tool.

2. Select the Surface-Surface connection analysis type and the Projection mode.

3. Select the Source text box and the source surface respectively.

4. Select the Target text box and the target surface.

5. Click the Quick button and select the analysis type: You will perform a Distance analysis (G0).

6. Set the maximum gap to 18 mm. This gap represents the maximum permissible gap between the surfaces.

The Quick Analysis displays the Max. actual gap of 17.4mm between the surfaces.

7. Click OK to retain the analysis results.

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Use the following steps to perform Quick connection analysis between the surface and curve in Projection mode:

1. Click the Connect Checker tool.

2. Select the Surface-Curve connection analysis type. (Projection mode will be automatically selected).

3. Select the Source surface and the curve.

4. Click the Quick button and select the analysis type: You will perform a Distance analysis (G0).

5. Set the maximum gap to 2mm. This gap represents the maximum permissible gap between the surface and the curve.

The Quick Analysis displays the Max. actual gap of 1.347mm.

6. Click OK to retain the analysis results.

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1.374mm

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Performing Porcupine Analysis on Surfaces

Porcupine Analysis tool helps to identify imperfections on surface boundaries.The analysis displays spikes normal to the boundaries. The magnitude of the spikes is based on the value of the curvature at each point and the direction is based on the curvature direction at that point. An inflection point occurs every time the curvature changes direction (a bump in the curve).

Interpretation at different edges:

A. Boundary at this edge is a straight line hence no spikes are displayed.

B. Boundary at this edge is curvature continuous, with the curvature remaining constant throughout.

C. Boundary in this area is curvature continuous with a smooth variation in the curvature magnitude.

D. Boundary in this area changes the direction of the curvature, hence you can see an inflection point.

Inflection Point: Curvature changes direction

A

B

C

D

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Curve Smoothing (1/4)

Curve will always transmit flaw to surface

Whenever you create any surface, it derives many of its characteristics from the wireframe used to generate it.

Surfaces inherit the flaws of the parent curve. In a product development cycle, this surface would be further used in down stream operations such as prototyping, machining, tooling, etc, thus affecting the final product.

CATIA provides you a tool to correct the discontinuities in a curve.

Curve with small flaw used to make a surface

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The Curve Smooth tool allows you to correct the discontinuities in a curve. It repairs flaws such as Point, Tangent and Curvature discontinuity of the curve.

When you select the curve to be smoothened, the tool indicates the discontinuities of the curve in a text labeled on the curve, in a graphic zone.You can obtain a desired smoothness in the curve by entering the smoothness parameters into the curve smooth dialog box.

Let us learn in more detail about the smoothening parameters in subsequent pages.

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When you select a curve to be smoothened, the command indicates the discontinuities on the curve. You can smooth a curve to a desired extent by specifying the Threshold value. This is a value which sets the upper limit of the discontinuity acceptance. Discontinuities of the curve below this value are considered for correction.

During the smoothening process, the curve gets deformed to achieve the specified continuity type. You can control the deviation of the curve after the deformation with respect to the input curve.

The threshold values for correcting tangency and Curvature discontinuities in a curve can be specified in the dialog box. You can decide the threshold value based on the quality acceptance criteria of your design or by the level of smoothness required on the curve. Smoothed Not Smoothed

Tangency Threshold

Not Smoothed Smoothed

Curvature Threshold value

Tangency Threshold

Curvature Threshold

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Use the following steps to create a smooth curve using the Curve Smooth tool.

1. Click the Curve Smooth icon.2. Select the curve to be smoothened.3. Check the value of discontinuity on the curve

a. Point Continuityb. Tangent Continuityc. Curvature Continuity

4. Specify the Tangency threshold value to attain the required smoothness of the curve (the threshold value also depends on the quality acceptance criteria for the curve in design context).

5. Specify the Maximum deviation value. This is the deviation you want to allow between the input curve and the smoothened curve.

6. Specify the Continuity value.7. Click OK to get the smooth curve.

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Healing Surfaces (1/3)

Heal tool is used to correct the defects (gaps, continuity problems) found by performing analysis between surfaces. Heal deforms the surface to fill up the gaps and reduces the tangency and curvature discontinuities.

Healing is a process by which one surface is deformed at a boundary to form a smooth transition into another surface. It will mathematically deform the shape of surfaces at boundary areas so that they smoothly blend into one another.

Before Healing

After Healing

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Healing is done to correct deformities pointed out by connect checker tool between surfaces.

Use the following steps to Heal surfaces

1. Click the Heal icon.

2. Select the surfaces that have to be healed.

3. Choose the type of discontinuity you want to heal. Here Tangency discontinuity is selected.

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4. To fill in the parameters for healing, edit the connect checker analysis that is done. The results of the connect checker analysis will help you to choose the parameter values.

5. Set:

a. Merging distance: 0.2mm.

b. Tangency angle: 6deg in field.

6. Click OK to confirm the healing operation. Now redo the connect checker analysis. It will give the following results:

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Recommendations for Surfaces Quality (1/4)

It is recommended that the input curves for the surfaces creation (spine, guides, sections)

should be tangent continuous. This minimizes the risk of flaws on the created surfaces:

A- The spine is not tangent continuous.The sweep inherits the faults of the spine.

B- The same spine has been made continuous. The default has been removed. B

A

Default on the surface

Tangency default on the spine

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Recommendations for Surfaces Quality (2/4)

There are two methods to create surfaces on sound continuous input curves:

A. Analyze the input curves with the Curve Connect Checker, detect the defects on these curves, correct the defects using the Curve Smooth tool and then use these curves for further surface creation commands.Note: By doing this, you have to be aware that the smooth tool implies a deviation from the original curve. The smoothed curve is different from the original curve: use the Maximum Deviation parameter in the smooth tool to minimize this difference.

B. Tolerant modeling: in some surface creation tools (such as sweep or multi-section surface), an integrated smoothing tool allows the use of input curves that are not continuous in tangency. The curve is smoothed on the fly and the surface does not inherit the curve defects:

B

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Recommendations for Surface Quality (3/4)

1. Superimposed surfaces

2. Free edges

3. Twisted surfaces

4. Micro-surfaces (surfaces which are too

small; smaller than the connection

tolerance)

A finished mode must not have any of the following flaws:

Superimposed surface

Free edges

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Recommendations for Surface Quality (4/4)

Corrective actionsFlaw detectionFlaw

Micro surfaces

Twisted surfaces

Free edges can be detected using the ‘Distance’ analysis of the Connect checker.

Free edges

Superimposed surfaces can be detected using ‘Overlapping’ option in Connect checker.

Superimposed surfaces

1. Heal these surfaces2. Trim these surfaces3. Delete and recreate the

surfaces

1. Heal these surfaces2. Join these surfaces3. Delete and recreate the

surfaces

Visual detection

Healing assistant

1. Remove these surfaces2. Fill gaps with a new

surface

1. Remove these surfaces2. Rework the surrounding

surfaces to correct the resulting boundary problems

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Deleting Redundant Elements (1/2)

1. Select Tools > Delete useless elements from the menu bar.

2. The Delete Useless Elements window shows all the elements of the part.

3. Select the element you want to keep and choose Keep from the contextual menu.

Useless Elements are the elements which have not been used to create any geometrical elements.

Use following steps to delete useless elements:

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Deleting Redundant Elements (2/2)

It is recommended to delete the useless elements in the finished model.

By deleting useless elements model structure becomes clear and easy to interpret.

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4. Keep mode is propagated to the elements which are associated to the selection.

5. Click OK to delete the remaining elements.

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

To Sum Up

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Transformation operations such as scaling and affinity, help to resize the part. Transformation operations such as translate and rotate, help to change the positioning of the part in the co-ordinate axis system.

In this lesson you will learn how to analyze curve connection, surface connections and to achieve the required continuities.

Analysis and Correction

� Extrapolating Elements: Extrapolates help to extend the curve or surface.

� Transformations: Transformations are used to modify the size, location, and orientation of a wireframe or surface element.

� Restoring Elements: Restores the limits of the surface or a curve which has been split once or several times.

In this lesson you will learn following operations:� Curve Connect Checker� Surface Connect checker � Curve Smoothing� Surface Quality� Deleting the Redundant Elements

Transform Surfaces

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Transformations

Translate: moves selected elements in a given direction and distance.

Rotate: moves selected elements around an axis.

Symmetry: creates mirror image of a selected elements about a plane.

Scaling: resizes a selected element with respect to a point or a plane.

Affinity: scales a selected element with respect to given direction.

Axis to Axis: duplicates and moves selected geometry from one axis system to other.

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Healing: correct the defects found after performing analysis.

Curve Smoothing: correct the discontinuities in a curve.

Untrim: restore the original surface from a trimmed surface.

Operations

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Main Tools

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Exercise: Surface AnalysisRecap Exercise

15 min

In this exercise you will perform surface analysis on the front wing surface using the analysis tools learnt in the previous steps. High-level instructions for this exercise are provided.


� Analyze surface connections

� Heal the discontinuities of the surfaces

� Analyze the radius and curvature on the surface

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2. Perform the Connect Checker analysis• Select the surface WING and click the connect checker

icon.• Select the Quick analysis mode .• Choose the G0 mode.• Study the gaps and severity on the surface.

1. Load Ex9C.CATPart.• Load Ex9C.CATPart. You will work on the

surfaces provided in this part.

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2. Perform the Connect Checker analysis (continued)• Activate the Tangency analysis• Notice the maximum discontinuities values

a. 0.015mm for distanceb. 0.437deg for tangency

3. Heal the surface• In the Healing Definition dialog box , specify the

following parameters.a. Click the Heal iconb. In the dialog box specify the following

parameters. Merging Distance: 0.02mm (> maximum distance continuity), Distance Objective: 0.001mm

c. Choose Point as Continuity.d. Click the Preview button. CATIA informs you of

the necessary deviation to heal the surface.e. Click OK to heal the surface.

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4. Repeat the Connect Checker analysis on the surface

ObservationYou will observe that the distance discontinuities on the surface are healed.

5. Perform Curvature analysis on the surface• Analyze the Limited radius of the healed surface• Notice the blue zone for which the radius is less than

10mm

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6. Using the porcupine analysis (as shown), analyze the curvature radius of the wheel arch

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Exercise Recap: Surface Analysis

� Analyze surface connections

� Heal the discontinuities of the surfaces

� Analyze the radius and curvature on the surface

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Case Study: Surface Modification ToolsRecap Exercise

10 min

Using the techniques you have acquired in this and previous lessons, create the model without detailed instructions.

In this exercise you will create the case study model. Recall the design intent of this model:

� Window opening (A) of the inner door must be reduced by 10% in X and Z directions.

� The lower door surface (B) must be curvature continuous.


A

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Do It Yourself: Create the Simplified Outer Door

Load Start_CaseStudy9.CATPart and modify the model using the information below.

� Affine the Window_Curve in X and Z direction using Center_Of_Gravity as the origin and use this curve to replace the previous Window_Curve.

� Perform the curvature analysis to find any discontinuities on the lower door surface.

� Smoothen the section curves of the lower door surface and use these curves to replace the previous section curves.

� Delete the useless elements to simplify the model.

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Case Study Recap: Simplified Outer Door

� Window opening of the inner door must be reduced by 10% in X and Z directions.

� The lower door surface must be curvature continuous.


Student Notes: Surface Modification Toolsyvonet.florent.free.fr/SERVEUR/COURS CATIA/CATIA... · 2012-09-25 · Student Notes: CATIA V5 Automotive - Body Lesson 9: Surface Modification

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