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Automotive Surfacing Techniqueswith Autodesk® Alias® SurfaceNils KremserMajor Accounts Automotive - Subject Matter Expert

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Introduction & Agenda

1 10:15–10:30“Automotive Shapes”

What is different here?

2 10:30–10:50Transitions & Continuity

Terms and Differences

3 10:50–11:00Surface Quality

Criteria

4 11:00–11:25Automotive Surfacing Techniques

Workflow demonstration: Which tools are necessary?

5 11:25–11:30Q&A

Discussion

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Automotive Shapes

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Car Exteriors

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Car Interiors

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„Automotive“ shapes

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What does „Freeform surface“ mean?

source: Wikipedia: “Freeform surface modeling”source: Wikipedia: “Freeform surface modeling”

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„Floating“ Shapes

For Floating

Highlights

You need Perfect Transitions

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Transitions & Continuity

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Explaining terms: Radius Comb

Radius plot: large radius = long comb

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Explaining terms: Curvature

Curvature plot: large curvature = long comb

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Transitions & ContinuityEXAMPLE

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Transitions

CAD Industrial Design ID / Automotive

Tangent Curvature G3 continuity

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CAD vs. Design shapes

CAD Industrial Design ID / Automotive

Tangent Curvature G3 continuity

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CAD vs. Design shapes

CAD Industrial Design ID / Automotive

Tangent Curvature G3 continuity

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Surface Quality

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Surface quality criteria

1. Number of Control Points: Fewer = Better!

3 point 4 points× 6 points ×

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Surface quality criteria

1. Number of Control Points

2. CV distribution

Proportional distances non-proportionally distances ×

All CVs follow positive shape CV does not follow positive shape ×

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Surface quality criteria

1. Number of Control Points

2. Logical CV distribution

3. Internal G3 continuity (rate of change of curvature)

Internal G3 continuity Internal G3 break ×

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Surface quality criteria

1. Number of Control Points

2. Logical CV distribution

3. Internal G3 continuity (rate of change of curvature)

4. Extendable

extendable not extendable ×

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Surface quality criteria

Single Surface:

1.Surface should be smooth: use just as few control points as needed!

2.Logical distribution of control points

3.Harmonic rate of change of curvature (internal G3 continuity)

4.Extendable

Multiple Surfaces:

1.Highlights: surface transitions in required quality (depending on size and material)

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Surface Quality

Without Surface Quality emotions don‘t work!

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Automotive Surfacing Techniques

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Modeling Workflow

Interior Data courtesy of EDAG

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Modeling Workflow

From Scan to Sections… … to centerline curves…

… creating quickly surfaces

EXAMPLE

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Which Modeling Tools are needed?

1. Basic curve & surface creation and modification tools

(draft / flange, square / rail / profile, revolve)

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Which Modeling Tools are needed?

1. Basic curve & surface creation and modification tools

2. Modifying control points

- move not only in x,y,z …

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Which Modeling Tools are needed?

2. Modifying control points

- move not only in x,y,z

but also

- in normal direction

- slide along the hull curves (tangents)

with lockable step size

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Which Modeling Tools are needed?

3. Align (matching surfaces)

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Which Modeling Tools are needed?

4. Fillet and Freeform Blend (with form factor)

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Which Tools to analyse and diagnose are needed?

5. Managing sections and planes

(x,y,z and radial sections,

„true“ / normal section,

interactive sections etc.)

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Which Tools to analyse and diagnose are needed?

6. Diagnostics

- Diagnostic Shaders (Zebra, iso-angle, Gauss etc.)

- Highlight and Parting line analysis

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Which Tools to analyse and diagnose are needed?

7. Visualization

- photorealistic

- but also

technical

(for design reviews,

shutline discussions

etc.)

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Which Modeling Tools are needed - Summary

1. Curve & surface creation

2. Control point modification

3. Align (matching surfaces)

4. Sections and plane manager

5. Fillets / Blends

6. Diagnostics

7. Visualization

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Learning Objectives

At the end of this class, you will be able to:

understand better what is special in Automotive modeling

explain what “freeform surfaces” are

describe criteria for surface quality

describe different levels of surface continuity

know why a regular CAD system is not a sufficient tool for Automotive modeling

which modeling tools & features are needed

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Thank you

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Any questions?

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