The hot desert where they filmed was actually about ten degrees Celsius (fifty degrees Fahrenheit). They were misting water on the actors to make it appear as if they were sweating.
Pitch Black (2000) was supposed to be a stand-alone film, but during production, Vin Diesel and the cast and crew had become intrigued by the Riddick character and the ending, in which Riddick was supposed to die. This was changed to leave an opening for a sequel with Vin Diesel returning. The film spawned three sequels, The Chronicles of Riddick: Dark Fury (2004) (animated), The Chronicles of Riddick (2004), and Riddick (2013).
Vin Diesel actually performed the shoulder-dislocation stunt (when Riddick breaks free for the second time) for the crew, holding a chain between his hands, although he couldn't do it with the cuffs on. The version we see is mostly him with some special effects thrown in.
Vin Diesel had an anxiety attack while inside the cryo-chamber as he felt he was trapped in there too long.
The contacts that Vin Diesel wore to play Riddick were a prototype. After the first day of filming, when they tried to remove the contact lenses, they couldn't. Due to where they were filming, they had to have an optometrist flown in from the nearest town, three hours away. Diesel called the contacts hubcaps.