Geomview is an interactive program for viewing and manipulating geometric objects, written by staff members of the Geometry Center. It can be used as a stand-alone viewer for static objects, or as a display engine for other programs which produce dynamically changing geometry. It runs on SGI and Sun workstations using generic X and Motif interfaces and is a much better display tool for 3-D objects than x3d.
To prevent myself from plagarizing too much I am going to let you get all of the details from the geomview manual which has an excellent overview section . However some key details you might find interesting are:
Version for Suns and SGIs.
Interactive 3-D manipulation.
Full control of object color, shading, and lights.
Geomview is better than x3d. It has more file support and more control over the rendered view. Geomview also has this freaky demo (NDemo) where they try to get you to visualize the 4th dimension. Try it out.