(written from a Production point of view)
Robert "Bob" Alex Diepenbrock (born 3 May 1949; age 68) was an employee at Industrial Light & Magic who was assigned as a model maker under Steve Gawley. He was among the team responsible for the construction of the two differently scaled USS Reliant studio models and their derivative partial counterparts for Star Trek II: The Wrath of Khan.
A California State University, Northridge graduate, with an Arts Bachelor's degree in "Theater and Communications", Bob Diepenbrock started out his career in theater, garnering "Best Actor" and "Best Director" awards, and having worked with the Los Angeles Shakespeare Festival. He added designing to his skill set, as well as photography, a result of which being his decision to start his own company "BobCat Studios" in 1978, before landing the position as visual effects artist at ILM.
While at Industrial Light & Magic, Bob Diepenbrock worked, besides The Wrath of Khan, on the model of the mothership for E.T. the Extra-Terrestrial (1982) and assisted on various films such as Raiders of the Lost Ark (1981), Poltergeist (1982) and set work for The Right Stuff (1983).
After he left ILM in 1984, he firstly accepted a position as senior producer-director position at KOB TV, the NBC affiliate in Albuquerque, New Mexico. While at KOB he earned his first Emmy Award for directing the documentary AIDS-The Threat Comes Home. In 1988 he moved to another NBC affiliate in the same capacity, KPNX TV in Phoenix, Arizona, earning that company three additional Emmy Awards for their productions. In 1992, he left KPNX to form his own, second, media production company, "Custom Creations". 
In 1996, Diepenbrock returned to visual effects for movie features by working for Digital Domain where he built the battle cruiser and Maundocheuan Ship for The Fifth Element (1997), then to Sony Pictures where he worked on model construction on all battle cruisers for Starship Troopers (1997). He later did the first sketch models for Buena Vista's Armageddon (1998).
Outside the motion picture industry, Bob Diepenbrock has continued to this day to operate his BobCat Studios company out of his current hometown, Chandler, Arizona, providing a wide range of non-motion picture clients with promotional services, such promotional films, photography and graphics.