[email protected] 3D Modeling: Surface Reconstruction and Surface Simplification 曾俊霖...

[email protected]

3D Modeling:3D Modeling: Surface Reconstruction Surface Reconstruction and Surface and Surface SimplificationSimplification

曾俊霖明新科技大學資訊工程系

2007/11/15 國立新竹教育大學資科所 /明新科技大學資工系

3D Modeling3D ModelingWhat is 3D Modeling?

◦ 3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object (either inanimate or living) via specialized software.

Why 3D Modeling?◦Virtual Reality is springing up.◦3D is friendlier than 2D.◦In the future

See a movie2007/11/15 國立新竹教育大學資科所 /明新科技大學資工系 2

3D Modeling3D ModelingHow to model a 3D object?

◦Sequential Engineering ( 順向工程 ) Creating an inexistent object. Using 3D modeling softwares.

3D Studio Max, Maya, …

◦Reverse Engineering( 逆向工程 ) Creating an existent object. Using production procedure of Reverse

Engineering

2007/11/15 國立新竹教育大學資科所 /明新科技大學資工系 3


3D(影像 /幾何 )擷取編輯系統

虛擬實境開發應用 /軟體

虛擬實境顯示融入操控模擬系統

Multimedia

Animation

3D CAD

Concave/ImmersiveConcave/Immersive

Studio/SDKStudio/SDK

OFF-Line

CD ROM CD ROM //Virtual ShowRoomVirtual ShowRoom

Mobile

ON-Line

Server/CollosseumServer/Collosseum

Mobile VisualizerMobile Visualizer

ConfiguratorConfigurator Support

Demonstrator Planner

Integrated

Digital Content

3D Studio MAXMaya

LightWavetrueSpace

ProESolidWorkSolidEdgeAutoCADArchiCAD

FlashDirector

資料庫

WEBWEB

ORACLEORACLE

ASPASPHTMLHTMLXMLXMLLinuxLinuxJAVAJAVA

VBVBVC++VC++

ActiveXActiveXMS AgentMS Agent

MovMovMP3MP3AviAvi

PPMPPM

Reverse EngineeringReverse EngineeringProduction procedure (Step 1)

◦Creation of a digital object A point-cloud model Using a 3D scanner


Reverse EngineeringReverse EngineeringProduction procedure (Step 2)

◦Creation of a meshed model Using surface reconstruction method


Surface ReconstructionSurface ReconstructionGenerating the triangles from a

point-cloud model


Surface ReconstructionSurface ReconstructionProblems

◦Which two points should be formed an edge?

◦How to decrease the time cost of generating a meshed model?


Surface ReconstructionSurface ReconstructionKey steps

◦Localized sampling Fixed-sized sampling approach

Alpha ball (sampling size determined by users)


α=∞α=0


◦Localized sampling Fixed-sized sampling

approach LVC (size determined by whole model

points) Proposed by Jong and Juin at CYCU in

2005 γ = γm + 3s

γm is the average of the distance from the closest point



◦Localized sampling Fixed-sized sampling approach

LVC (size determined by whole model points) Problem: some undesired edges are generated.



◦Localized sampling Adaptive-sized sampling approach

Projected-based approach Proposed by Gopi in 2002 Using the nearest point to determine the sampling

region r= μ x m Dense points are necessary. Small holes might be generated.



◦Localized sampling Adaptive-sized sampling approach

Shape-based approach Proposed by Jong and Juin Summit to JCST(SCI Journal) - 2nd revised Using DSO(Discrete Shape Operator) to

determine the sampling regions


Surface ReconstructionSurface Reconstruction

Key steps◦Sampling points pruning

Points lying on different surfaces



◦Sampling points pruning Points lying on different surfaces


Surface ReconstructionSurface ReconstructionCurrent Results


Surface ReconstructionSurface ReconstructionAnother problem

◦The reconstruction of high-variation surfaces fails easily. Solution

Extracting high-variation surfaces before reconstructing◦The number of points is too many

Increasing of computation cost Increasing of storage cost Solution

Removing some irrelevant points and triangles Using Surface Simplification Method


Surface SimplificationSurface SimplificationReduce the points and trianglesProblems

◦Which points, edges or triangles should be removed?


Surface SimplificationSurface SimplificationRelated Methods

◦Vertex Removal removing a vertex from 3D model, along with its

adjacent edges and triangles, and retriangulating the resulting hole.

Only for manifold surface


Surface SimplificationSurface Simplification

Related Method◦Vertex Clustering

It cannot maintain the quality.



◦Edge Collapse Edge collapse can contract an edge to a single

vertex. This approach can be used for manifold and non-

manifold models, but can close holes in the model.



◦Vertex-Pair Contraction Using QEM(Quadric Error Metric) to

determine the rank of vertex-pair contraction


Surface SimplificationSurface Simplification

Related Methods◦Multiphase Approach

Combining the uniform-clustering method and vertex-pair contraction

For large-size models

◦User-Guided Simplification This method aims to overcome the problem

of vertex-pair contraction to retain the object features.

Retained features determined by users


Surface SimplificationSurface SimplificationOur approach

◦Using Shape Operator to retain the object features automatically


Surface SimplificationSurface SimplificationShape Operator

◦Merge curvature and Torsion


Surface SimplificationSurface SimplificationVertex-Pair Contraction vs our approach


Feature ExtractionFeature ExtractionExtracting features before

surface reconstruction◦It can avoid the failure of

reconstruction of high-variation surfaces

Extracting features before surface simplification◦It can effectively retain the features

of a simplified model.


Feature ExtractionFeature ExtractionCorrelation ellipsoid


Feature ExtractionFeature Extraction

Multi-scale feature extraction


Feature ExtractionFeature ExtractionTime cost is very high.Low-cost feature extraction

method is necessary◦Using DSO to extract high-variation

surfaces


Feature ExtractionFeature ExtractionFor point-based models


Feature ExtractionFeature ExtractionFor meshed models

◦1-ring neighbors


Feature ExtractionFeature ExtractionPoint-

based models


Feature ExtractionFeature Extraction

Meshed models


Computer Graphics in the Computer Graphics in the FutureFutureA movie generated by NTT in

Japan◦NTT Docomo -Vision2010

2003~2010 <movie>

◦NTT Docomo -Vision2010 198x~201x <movie>


[email protected] 3D Modeling: Surface Reconstruction and Surface Simplification 曾俊霖...

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