XU Shuhong, HENG Chye Kiang, SUBRAMANIAM Ganesan, HO Quoc

Thuan, KHOO Boon Tat

Interactive Visualization Interactive Visualization of Largeof Large--Scale Scale Architectural Models Architectural Models over the Gridover the Grid

AgendaAgenda

• Motivation• Objective• A Grid-Enabled Visualization Infrastructure• Multi-Stage Data Compression• Prototype System Deployment• Summary

MotivationMotivation

• Virtual reconstruction of Tang period Chang’an city

• How to enable remote users with PCs to explore this splendid ancient city?

ObjectiveObjective

To explore Grid and visualization techniques and to formulate an appropriate framework for interactive remote rendering of large-scale architectural models

A GridA Grid--Enabled Visualization Enabled Visualization InfrastructureInfrastructure

• The promise of Grid computing: “a transparent, interconnected fabric to link data sources, computing (visualization) resources, and users into widely distributed virtual organizations” (Shalf and Bethel 2003)

• Relevant works (next slide)In summary, Grid-based visualization, especially for large-scale data, is far from mature till today

System/app-roach

Brief Description Limitations Others

Vizserver Rendering is done at server site

SGI super-computer only

Commercial

vCollab Sending data to each collaborator

No data protection

Commercial

Access Grid (AG)

Open source group-to-group teleconferencing tool

Not designed for rendering

Several systems have been deployed over AG

gViz project Grid extension of IRIS Explorer & pV3

Developed for these two software tools

Research

Grid Visualization Kernel(GVK)

Aimed at a universal Grid visualization service

No user interaction

Research

RAVE A resource aware visualization system

Not designed for large-scale data

Research

Grid-enabled visualization

Remote & collaborative visualization

• Infrastructure of A-VizGrid (architectural visualization Grid)

Grid resources are used to do computation and handle data. On top of a resource, a visualization or data service can be deployed. These services are registered into a centralized information service so that they can be located by a visualization planner. A visualization or data service runs within its execution service container which deals with communications over the Grid using Grid-compliant protocols

User

request

display

Portal Server VisualizationPlanner

InformationService

Data Service

executioncontainer

VisualizationService

executioncontainer

data source

data processing

data transferdata receiver

rendering

frame buffer

data transfer usingGripFTP

imagecompression and

transfer using UDP

userinteractions

launch ofapplications

launch ofapplications

inputpara-

meters

resource inforesource info

resource inforeply

resource inforequest

Infrastructure of A-V

izGrid

• Considerations of A-VizGrid- Sharing rendering burden over the Grid

(1) make use of remote rendering facilities(2) protect designers’ ownership of 3D models

- Large data sets through limited network bandwidth(1) distribute rendering tasks to a limited number of powerful rendering facilities connected by high-speed networks(2) use data/image compression techniques

- Launching applications through execution service containers

MultiMulti--Stage Data CompressionStage Data Compression

• Pre-processing stage- divide the city into districts- simplify 3D models

• Rendering stage- view-dependent culling- level of details (LOD)- data paging

• Remote display stage- image compression and decompression

Dividing the city into districts

Simplifying models into different resolutions

1:32 compressed by the SGI Vizserver

algorithm

1:128 compressed by a new wavelet algorithm

Prototype System DevelopmentPrototype System Development

• Based on the A-VizGrid infrastructure, an experimental prototype system is being developed

• Deployment of the prototype system- the Chang’an city models are kept at National University of Singapore- available rendering facilities include a SGI Onyx2 with four graphics pipes at the Institute of High Performance Computing (IHPC), a Linux cluster with 10 AMD64 Opteron CPUs and 5 Nvidia Quadro FX3000G graphics cards at IHPC, and a SGI Onyx3000 at Nanyang Technological University

- rendering software tools include OpenGL Performer with enhanced culling and view-dependent continuous LOD algorithms, VRCO CAVELib, and Chromium, etc

• OGSA-based Grid services- information service- visualization planner - execution service container (using Java, completed)

• A simple demonstration of distributed rendering using Grid services and execution container

SummarySummary

• To enable remote users with normal personal computers to interactively visualize large-scale architectural models, a Grid-based visualization infrastructure A-VizGrid is proposed

• The underlying Grid services are developed according to the OGSA standard

• A multi-stage data compression approach is used to improve rendering speed.

Thank YouThank You