An experimental IRIX version of VRED is now available, which is, according to their website, a "Virtual Reality System for visualization of complex 3d Scenes. For interaction a Action/Event aproach is used. It is based on the great open source Renderer OpenSG."
The Lite version is a free download - there is also a Pro version which requires a license but it isn't clear if an IRIX version exists for that one at this point or not.
