RoboCop's costume was not finished until sometime into filming. This did not impact the filming schedule, but it denied Weller the month of costume rehearsal he had expected. Weller was immediately frustrated with the costume because it was too cumbersome for him to move as he had practiced; he spent hours trying to adapt. He also struggled to see through the thin helmet visor and interact or grab while wearing the gloves. He fell out with Verhoeven and was eventually fired, with Lance Henriksen considered as a replacement; but because the costume was built for Weller, he was encouraged to mend his relationship with Verhoeven. Yakim helped Weller develop a slower, more deliberate movement style. Weller's experience in the costume was worsened by warm weather, which caused him to sweat off up to per day. He began taking prescription medication to cope with stress-induced insomnia, which left him filming scenes "under the influence".