The Volume Rover

Center for Computational VisualizationInstitute for Computational Engineering and Sciences

The University of Texas at Austin

Shashank Khandelwalshrew@cs.utexas.edu

Outline of Tutorial

• What is the volume rover?• Features & requirements• A description of the interface• Demonstration• How can I get it?• Let’s all try it out & questions

What is the Volume Rover?

• A texture based volume rendering client

• With a multi-resolution zoom feature

• A front end to our parallel volume rendering servers

Features

• Multi-resolution zoom feature• No dataset size limitations• Loading data is fast after the first time• Simple interface• Connects to DataCutter (www.datacutter.org)

Requirements

• Qt 3.0+ library (free for Linux from http://www.trolltech.com)

• Nvidia GeForce 3+ ($80 - $100 retail)

• CORBA libraries• It’s portable! Since the rover is a C++/Qt

application, it can run on Windows, Linux/Unix & Mac OS X.

A Description of the Overall InterfaceSubvolume

viewerExplorer Subsampled version of entire dataset

Colormap EditorEdit the transfer

function

Viewing Parameters

Adjust rendering quality and set near

clip planes.

Subvolume ControlMove and size the

subvolume

• Pre-processing step the first time you load a data file.

Opening Files and Pre-processing

32 Mb 11.93 s626 Mb 220 s

• Pre-processing time scales linearly with the dataset size

Rawiv

• The rawiv data format is used to represent 3D volumetric data of scalar fields defined on a regular grid.

• A complete description of the rawiv file format can be found here:

http://www.ticam.utexas.edu/~shrew/formats/rawiv.html

Editing the Transfer FunctionYour visualization is as good as your transfer function

Horizontal axis represents density, with density increasing from left to right

Vertical axis

represents opacity

(increasing from

bottom to top)

Color nodeLine segments represent opacity function Alpha node

Editing the Transfer Function (2)

Transfer function files must be called *.vinay

Selecting a Subvolume

• Click & drag on axes to move

• Click & drag on ends of axes to size

Demonstration

Let’s see it in action!

Connectivity

• Client can connect to a DataCutter server• Client can connect (using CORBA) to our

parallel visualization services• Come by during the poster session for a

demonstration. We’ll be in the SDSC Vislab.

(There will be some food there)

Upcoming Improvements

• Ability to create animations• Save images from the client• Shaded volume rendering • Isocontouring

How can I get it?• A Windows and Linux version is

downloadable from the software section of our website:

• http://video.csres.utexas.edu:8000

CreditsDr. Chandrajit Bajaj (bajaj@cs.utexas.edu)

Vinay Siddavanahalli (skvinay@cs.utexas.edu)*Anthony Thane (thanea@ticam.utexas.edu)

& others at CCV

Let’s All Try It Out

• Open a dataset • Play with the transfer function editor

• Edit color node• Add alpha node

• Learn how to move & size with the sub-volume control

• Try the render quality & clipping plane sliders

Come up with a good transfer function