(written from a Production point of view)
Thomas Mahoney (or simply Tom Mahoney) is credited as a scenic artist on Star Trek Nemesis along with Shawn Baden, Monica Fedrick, Rick Sternbach, and James Van Over. Prior to this, Mahoney was the editor and visual effects supervisor of the Star Trek World Tour.
Mahoney and fellow Nemesis scenic artists Monica Fedrick and Rick Sternbach also worked as graphic artists on the 2002 film Solaris. It was Mahoney and Fedrick who recommended Sternbach for the assignment. 
Mahoney works primarily in visual effects. He was the digital artist on the 2001 film Scary Movie 2 and television programs such as Seven Days and Level 9. He was employed as an inferno artist for shows like Martial Law and Resurrection Blvd. and the 2003 film Freddy vs. Jason. In addition, he was a digital compositor on the series The Division and the films Kiss the Girls, Swordfish, The Chronicles of Narnia: The Lion, the Witch and the Wardrobe, Final Destination 3, and The Guardian. He was also visual effects supervisor on the LeVar Burton-directed TV movie The Tiger Woods Story and the 2005 film Two for the Money and served as digital visual effects supervisor on Exorcist: The Beginning.