It features phong shading, emitting light from brush entities, more realistic directional sunlight, special checking in order to prevent light "bleeding" through solids etc.
Hammer/J.A.C.K./Sledge and Trenchbroom users: this will require a modified FGD file. Add keyvalues manually until then, or edit your own.
Version 2.00: March 2, 1999
* program: added phong shading
* program: added _sun_surface feature
* program: rewrote sunlight code to be more efficient
* program: rewrote anti-light-bleed code to improve quality
* program: fixed qrad3 black-band & splotchy sky/liquid light bugs
* program: fixed qrad3 surface #0 bounced light bug
* program: improved command-line option output
* program: removed some now-unused qrad3 code
* text: added new feature info, made minor tweaks elsewhere
* text: added John Fitzgibbons to acknowledgments
Version 1.50: November 2, 1998
* program: added direct-lighting of unvised maps
* program: added FreeDirectLights() to reclaim memory
* program: added light-bleed checking and -nostopbleed
* program: tweaked speed and memory use in some areas
* program: added -radmin cutoff
* program: rewrote texture handling code to be more efficient
* text: added new feature info, made minor tweaks elsewhere
* text: added Mr Elusive to acknowledgments
Version 1.03b: September 17, 1998
* program: fixed -moddir to read all pak#.pak
Version 1.03: September 17, 1998
* program: fixed ambient & minlight bug from original qrad3
* program: tweaked -gamedir/-moddir to not require final backslash
* text: _sun_angle clarification
Version 1.02: August 24, 1998
* program: fixed spotlight _focus lighting bug
* program: fixed bad _ambient lighting in worldspawn
* text: added -nominlimit info
* text: added Michael Meadows to acknowledgments, added webpage URL
Version 1.01: April 30, 1998
* program: eliminated crashes with multiple suns using _sun aiming
* program: fixed -chop* and -nobmodlight settings messages
* program: fixed the spelling of "square" in verbose mode
* text: corrected Rich Tollerton's name in acknowledgments
* text: negative light clarification
No version change: April 8, 1998
* text: -gamedir/-moddir correction
No version change: April 7, 1998
* text: sunlight correction
Version 1.0: April 7, 1998
* first release
The download was found at the download page of BSP, under the Mapping Tools section. I was unable to retrieve it from the original ArghRad site (on the Web Archive), which has been down for a long time.
