Dissatisfied by the look of modern computer generated visual effects, director Terrence Malick approached veteran special effects supervisor Douglas Trumbull, who was responsible for the visual effects in 2001 - Odyssee im Weltraum (1968), to create the visual effects for the film using bygone optical and practical methods. This marks the first feature film Trumbull has provided the effects for in 29 years, his last being Der Blade Runner (1982).
The butterfly that landed on Mrs. O'Brien's (Jessica Chastain) hands was not CG but a real one. One morning while both Chastain and Brad Pitt were rehearsing, Terrence Malick spotted it flying around. He got the crew and Chastain following it three blocks of Smithville, then got her to step into the middle of a street and hold her hand up.
The critic Jim Emerson got word of what Terrence Malick intended the sequence of dinosaurs to mean, by way of the visual effects supervisor in charge of that very sequence who is Michael L. Fink. Emerson describes what he learned from Fink; "The premise of the four-shot scene was to depict the birth of consciousness (what some have called the "birth of compassion")-the first moment in which a living creature made a conscious decision to choose what Michael described as "right from wrong, good from evil." Or, perhaps, a form of altruism over predatory instinct".
According to Emmanuel Lubezki, a whole movie focusing on Sean Penn's character could be made from cut footage.
The town of Smithville, Texas was chosen because the practical structure houses still mirror the '50s settings required by the film. It is one hour's drive from Austin, Texas with a population of only 4500 people. While the crew was filming there, there was no additional lighting equipment being used and camera equipment was stored at a rented garage.