ADVANCED VISUALIZATION OF ADVANCED VISUALIZATION OF ENGINE SIMULATION DATA USING ENGINE SIMULATION DATA USING

TEXTURE SYNTHESIS AND TEXTURE SYNTHESIS AND TOPOLOGICAL ANALYSISTOPOLOGICAL ANALYSIS

Guoning Chen1, Robert S. Laramee2 and Eugene Zhang1

1. Oregon State University, Corvallis, Oregon, USA. {chengu, zhange}@eecs.oregonstate.edu2. Swansea University SA2 8PP, Wales, United Kingdom. Laramee@swansea.ac.uk

OutlineOutline

• Introduction• Vector field background• Texture-based vector field visualization• Vector field topology extraction• Vector field simplification• Results• Conclusion

IntroductionIntroduction

• Applications

• Requirement of engine design

• Current vector field visualization methods

Vector Field BackgroundVector Field Background

• Vector field

x=V t , x X⊂Rn

is a function which associates a vector u to each point x of U at time t time t

Vector Field BackgroundVector Field Background, continued, continued

• The topology of a flow consists of

– Fixed points• Sources• Sinks• Saddles• center

• Flow topology– Separatrices

• Incoming• Outgoing

– Trajectories

gradient-like

Vector Field Background, continued

dr t / dt= V r t

Texture-Based Vector Field VisualizationTexture-Based Vector Field Visualization

• Previous work

4) feature based4) feature basedTopology skeletonTopology skeleton[Helman&Hesselink][Helman&Hesselink]

1) direct Arrow plots, iconsArrow plots, icons

2) geometricStreamline[Jobard et al, Turk et al.]

3) texture based Spot noise[van Wijk], Spot noise[van Wijk], LIC[Cabral&Leedom]LIC[Cabral&Leedom]UFLIC[Shen &Kao]UFLIC[Shen &Kao]AUFLIC[Liu et al.]AUFLIC[Liu et al.]DLIC [Sundquist]DLIC [Sundquist]LEA [Jobard et al.]LEA [Jobard et al.]UFAC[Weiskopf et al.]UFAC[Weiskopf et al.]

Texture-Based Vector Field VisualizationTexture-Based Vector Field Visualization, , continuedcontinued

• Image-Based Flow Visualization (IBFV)

Image credit: van WijkImage credit: van Wijk

Texture-Based Vector Field VisualizationTexture-Based Vector Field Visualization, , continuedcontinued

• Image Space Advection (ISA) & IBFVS

Vector Field Topology ExtractionVector Field Topology Extraction

• Previous work

• Fixed point extraction

{F x , y =axbycG x , y =dxey f

x1 y1

x 3 y 3

x2 y 2 F 1 G1

F 2 G 2

F 3 G 3

Vector Field Topology ExtractionVector Field Topology Extraction, , continuecontinue

• Separatrix calculation

Vector Field SimplificationVector Field Simplification

• Previous work

– Non-topology based (NTB)• Smoothing vector field potential [Ying et al.]

• Componentwise smoothing [Alliez et al.]

– Topology-based (TB)• Pair cancellation [Tricoche and Scheuermann][Zhang et al.]

Vector Field SimplificationVector Field Simplification, , continuedcontinued

• User-guided smoothing (A NTB smoothing)– Componentwise smoothing

v

u

θ2θ1

Before smoothingBefore smoothing

Vector Field SimplificationVector Field Simplification, , continuedcontinued

• Componentwise smoothing

v

u

θ2θ1

?

ω ij is computed by using is computed by using mean value coordinatesmean value coordinates

Vector Field SimplificationVector Field Simplification

ResultsResults

ResultsResults, continued, continued

ResultsResults, continued, continued

• Performance report

7.644.483.16226886,296Diesel engine

9.259.090.1656105,192Gas engine

timetotal(s)

time computingseparatrices(s)

times extractingfixed points (s)

# offixed points

# ofpolygons

datasetname

((The experiments are carried out on a PC with 3.6GHZ CPU and 3GB RAMThe experiments are carried out on a PC with 3.6GHZ CPU and 3GB RAM ) )

AcknowledgementAcknowledgement

• We would like to thank Christoph Garth, Konstantin Mischaikow, Juergen Schneider and Greg Turk for their valuable contributions.

Thank Thank you!you!