Trivia

An anatomically correct, totally working computer model was created of Kevin Bacon's entire body - down to the last capillary. The 3-D model has since been donated to scientific researchers.

During filming, Kevin Bacon wore skin-tight costumes in green, blue, grey, or black, to assist with the adding of visual effects. Some of his cast mates said that the hardest part of the role was not laughing at someone painted in black, green, blue, or grey, pretending to be mean.

Bacon admitted that he accepted the role partly under the false assumption that he wouldn't need to be on set for scenes of Sebastian invisible, and that it would be an easy performance. He claimed that to the contrary it ended up being the most physically demanding and difficult role of his career.

To get the right reaction from the cast, Paul Verhoeven had speakers put in different places on the set, and had Kevin Bacon's voice come from different speakers so the cast would genuinely react to the invisible character moving around. For the scene with the invisible gorilla, Verhoeven screamed to the microphone, imitating gorilla noises.

Despite assumptions that Kevin Bacon would not be needed on set, except when his character Sebastian is visible, Paul Verhoeven and the crew realized after test footage was shot, that he would need to be present, to interact with the cast, as "the other actors were stranded in empty space, and the scenes looked stiff, inorganic, and unconvincing" without him.

Hollow Man was one of very few films allowed to shoot directly in front of The Pentagon building, with Paul Verhoeven expressing surprise that the script was approved, because of the themes of the United States Government commissioning scientific experiments into making living beings invisible.