Review the license (version 1.0).
OpenDx 4.2.0 is the latest (20 May 2002) tarball.
OpenDxSamples 4.2.0 contains the latest samples.
Browse the tarball download directory (this is not the cvs download directory mentioned below).
OpenDx CVS contains the current project source.
To compile and link OpenDX, you may have to download some other software packages.
You will need to have OpenGL installed to get compiles to work. If your platform doesn't have its own OpenGL, then you might consider downloading the Mesa libraries.
If you wish to include support for the CDF, NetCDF and HDF file formats, you must download and compile the libraries.
This is frequently part of a development installation. If it isn't on your system or on your installation media, see e.g. www.xfree86.org.
The user interface requires Motif libraries. for open source versions check out lesstif and openmotif.
ImageMagick is now used by OpenDX to export most image formats. Install ImageMagick if you wish to use formats in addition to the few that OpenDX exports natively.
A Java development kit e.g. jdk 1.1.8 is needed to enable the "javadx" features, i.e. the ability to export your visual programs as html pages with applets and run them from a web server. The dx "configure" script requires that a javac that supports the --verbose option be in your path. See e.g. www.sun.com/java or www.ibm.com/java