Collaborative Scientific Data Visualization

FrameworkKi, Klasky, Fox

Syracuse University (NPAC)scott@npac.syr.eduS

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SV2 Features

• Java2D (promise for fast 2D rendering/animations).

• Java3D (promise for fast 3D graphics on all platforms).

• Voluminous data server (compression schemes to allow for fast data transfers).

• Multiplexing (efficient collaboration data server along with TANGO)

OBJECTIVE• Our goal of this collaborative system is to use recent computing technology, Java, to build a multi-user collaborative scientific design and analysis environments which can run on all platforms.

• The objective was to develop the scientific software environment where multiple users can create, share, manipulate, analyze, simulate, and visualize complex data sets over a heterogeneous network of PC’s, workstations and supercomputers.

Scivis->SV2

• Our SV2 research and design is based on the success of Scivis. Scivis is a collaborative scientific data visualization package written in Java.

• Scivis allows users to visualize their data, which is piped in via sockets.

• Although Scivis has been widely used in the “Binary Black Hole Grand Challenge”, it still had major limitations.

• One of the most common complaints against Scivis was that users could only collaborate with other Scivis users.

• SV2 is being designed such that users of Scivis3d (a Java3D version of Scivis), AVS, & VRML can collaborate together.

SV2 System ArchitectureLocal Client

Client Manager

Data Viewer 1

Data Viewer 2

Local Client

Client Manager

Data Viewer 1

Data Viewer 2

CollaborationTool

Geometry Engine

Filter Engine

SV2 Server

Sample Screen Dump

RaytracingRotations of raytracing Surface & Contour Plots

IsosurfacesX,y animations

USE JNI to incorporate quality visualization code.

• The Stanford Volpack routines for raytracing. (written in C).

• Isosurface rouintes with • We provide API’s too incorporate such routines into

the SV2 server with minimal pain.

• Eventually we will provide API’s to incorporate VTK filters too. (C++ routines)

– Users can customize routines for their own use.

Future Work• Filter/Map creator, users can hook filters together, and create new API’s for

those maps.

Compression

Downsize

Smooth

Isosurface

decimation

Mysv3d(name,time,g3d,n)

Downsize

VTK:raytrace

Compression

Myray(name,time,g3d,n)

SV2-Client Window• Data is sent from simulations, or files, to the

SV2 server.

• Data from the SV2 server is stored (in memory, and on disk).

• Data file headers are sent to SV2-clients.– Clients can request to visualize the data.

• To keep support for Scivis alive, we allow users to pipe data directly to SV2 clients.

• For enhanced interactively, the image should be refined progressively as the data comes in from the remote server.

– Image quality must be controlled as a function of the network's load and client's hardware setup.

• In order to store and transmit large scale data sets, compression schemes have to be utilized.

– In order to avoid full decompression, a sophisticated rendering method should carry out computations in compression domains at the client side.

– For the above two issues, wavelet compression is an obvious choice in our system.

SV2: Issues for rendering

• With upcoming network computers, the capabilities of a local client might be reduced significantly.

– A data representation and rendering method is required, which will avoid the full expansion of the data in the clients memory.

• Java-3D allows programmers to specify geometry using a binary geometry compression format. This compression format is used with APIs, and can be used both as a run-time in-memory format for describing geometry, as well as a storage and network format.

SV2: More issues

SV2: Visualization

• Once Data-headers are on the client, users can select different methods to visualize the data.– For example, for a 3D data set, users can select either isosurface

or raytracing.

– Users can also select methods to filter this data, such as triangle decimation.

• Clients request data from the server, the server performs the appropriate filter(s), and then sends back the geometry (or image, or actual x,(y,(z)) data) back to the client.

• The client (Scivis3D,VRML(not yet implemented)) visualizes the data.