At SDCC movie panels, directors owned up to falling behind schedule because of having . to invent SFX along the way:

Directors also apologized for slipped movie release dates, pointing to difficult visual effects for the delay. “We had to come up with a whole new program to create the fire, and to be honest with you, that’s the reason it’s been taking so long to finish the film,” Mark Steven Johnson, the director of “Ghost Riders,” told the crowd on Saturday. “A lot of the Sony Pictures Imageworks effects were groundbreaking. Sony Pictures unveiled at Comic-Con first-time footage of “Ghost Rider,” an adaptation of Marvel Comics hero Johnny Blaze who sells his soul to the devil to save his father. The event brought out Johnson, along with producers Michael De Luca and Avi Arad and stars Nicolas Cage and Eva Mendes. More than 6,500 fans packed into Hall H, the convention center’s biggest room, to see the fiery visual effects.

Johnson said Cage, who plays lead character Johnny Blaze, wore a green neoprene hood over his head with interactive lights to mark the spots that fire should appear. “We’d get his expressions and movement, then digitally remove his head and put the flaming skull in its place,” he explained.