Style means that when an actor performs calligraphy, painting, sculpture, design, copywriting and other plots, it is impossible for him to know those techniques, so he needs to use style to complete the shooting for him. Style generally only shows hands or back.
Martial arts means that when an actor performs martial arts, fighting, jumping, flying, sports and other plots, the actor himself can't know those kung fu skills and needs the help of martial arts to complete the shooting for him. Wu Ti can't see his face clearly when he is moving fast.
Naked replacement means that when an actor performs some scenes that need to leave the country naked, because the actor himself is a big name and doesn't want to perform such scenes, he needs to use naked replacement to complete the shooting for her. Naked replacement will only be used if the actor is a big name or the actor's body is really not suitable for nudity. Ordinary actors or newcomers have no right to use nudity. If they are healthy, they must go into battle by themselves.
Light substitution means that the actor's position needs to be selected in advance before a scene audition, and he should stand there and wait for the lighting engineer to adjust his position, or wait for the cameraman to see the right position in natural light. Sometimes, when shooting a scene in the rain, it is necessary to choose the actor's position in the rain in advance. If it is artificial rainfall, it is necessary to adjust the amount of rainfall and the falling position according to the position of the actor. At this time, if a big-name actor wants to perform this scene, it is impossible for him to stand there for a long time, let alone stand there in the rain for a long time. Therefore, body double should be used instead of big-name actors.