BioViewer is a Java OpenGL -based visualization tool for viewing/analyzing biological structures, proteins and DNA.
Source: CSE-Online
Features
Different viewing modes, namely Sticks, Balls&Sticks, Overlapping Spheres, Ribbon, and C-alpha backbone (for proteins).
Special selection of different residues, fragments, segments of the structures for different view modes
Measuring bond distances and angles
Print and Save image
Known problems
There're two kinds of highlighting on atoms. One is from picking, the other is from selection on Tree or search subdialog. Default colors are purple and green respectively. Puple highlighting is for defining input of measuring operation and green highlighting is to show the atom selected by selection operation from already known atom/residue/chain information.
When you failed to see purple hilighting after clicking on a atom, rotate the scene so that the other graphical elements around the atom has changed. It eventually works.