Former Rockstar Games animator Mike York, who worked on GTA V, recently spoke with TGG. He received a question about the physics of "swaying" body parts from the Grand Theft Auto VI trailer — it attracted the attention of many players.
According to Mike, the physics of movement can be created in different ways. For example, animators can program the game engine to recognize the weight and speed of certain body parts.
However, York suggests that in the case of Lucia from GTA VI, the physics of swaying was "most likely" implemented by placing as many "bones" as possible inside the heroine's buttocks (skeletal animation).
These "bones" work in conjunction with the rest of Lucia's skeleton, thanks to which animators can program how much this part of the girl's body will be subject to the influence of physics and movement.