ViewDog is a viewer for nurbs functions, polygonal geometry, and to some degree for iso surfaces of functions over a 3D domain (via marching cube). It also can be used as a graphical frontend for a number of interpolation and approximation algorithms contained in a seperate library (GUL). Import and export via Alias Wavefront 3.0 OBJ files is possible, so it can be used simply as a viewer for OBJ files, too.
gstar provides a GTK frontend for "starchart", a program written in 1987 by Alan Paeth. The frontend offers a list of pre-defined areas of the sky to chart, plus controls to customize the chart in several ways. Buttons pop up a given postscript chart in gv, or save it to file. Since Paeth's program is freely distributable the source for starchart (along with data files) has been rolled into the gstar package, making it self-contained.