CMSC 636: 
Data Visualization

Computer Science and Electrical Engineering Department 
University of Maryland Baltimore County

Visualization Construction Assignment

Due: September 23, 2005

Project Description

In this assigment you will create a variety of simple scalar visualizations and an interactively controllable camera with which to view them. In the process you will become more familiar with the range of visualization options available and how to accomplish what you want in vtk. Many of the group projects may later build upon this framework.

What to do

Write vtk scripts which:
  1. create two very different visualizations of two different 2D scalar data set (two visualizations for each data set -- four total). Possibilities include:
  2. provide interactive control of the visualization. Options include: You should set things up so that this code can be used by any similar scripts you write.
  3. Annotate your visualizations appropriately with things such as bounding boxes, axis labels, legends, etc.

The data

The data files for this assignment can be found in:
     /data/gavl2/data/636/

What is vtk?

vtk is a visualization library with a Tcl/tk interface (among others). You can write visualization code using either Tcl or C++ (or other options). For this assigment, the Tcl interface is probably easiest. The vtk User's Guide gives really good examples of common visualization techniques. Documentation of vtk objects and methods is available online. Other information about using vtk is also available on the vtk home page. vtk is available locally on Alternatively, you can also install vtk on the machine of your choice (running UNIX, Linux, Windows). Download the latest version from the vtk home page. If you use a machine other than those in cs for development, the version you turn in must also run properly on a cs machine. This should require only trivial modifications (if any), but they're your responsibility.

Running vtk scripts

Before you run vtk, you will need to set up various environment variables.
  1. Set the VTK_DATA_ROOT variable to indicate the location of the datasets. In tcsh, this can be done using the command setenv VTK_DATA_ROOT "/data/gavl3/IDtkRelease/vtk-new/VTKData"
  2. Add /data/gavl3/IDtkRelease/vtk-new/bin to your system path, to facilitate use of the vtk executable in any directory

To run a script, make sure that the correct bin is in your path and type: 

	vtk yourscript.tcl
where yourscript.tcl is the name of the script that you have written.

How to begin

Example vtk scripts are available in (vtk root)/src/VTK/Examples. Some other scripts are included in the User's Guide (these generally have more explanation than the ones online). Try a few of these scripts to get the hang of how they work. Then use a simple one as a template for your script.

What to turn in

Turn in your vtk scripts by submitting your scripts using the command 
submit cs636 Proj1 files_names
All necessary pieces should be included and data file pathnames should be absolute so that they work from anywhere. You should also submit copies of the images produced by by your scripts. The header comments should describe the visualization and the user interface and specify which cs machine you think this runs on. Your comments should also credit any source material you used (for instance, the vtk scripts that you used as templates or classmates who gave you help on getting vtk to do what you want). In-line comments are left to your discretion, but may increase your partial credit in the event that your program does not work as intended.