Gamespot has posted another Q&A session with Rockstar North regarding game physics, AI and modding in the upcoming PC release. While most of the information will be old news for PS2 gamers (and quite a few PC gamers as well), technical details seem to have become much more "sophisticated" now that we're enterting the PC realm:
|"The buoyancy forces that are applied through the physics engine are calculated based on the percent volume of an entity that is underwater. In the case of the CJ or characters, this is simply based on the height of the water level up the character's body as a percentage of their height. For a vehicle, we must sample the water level at various points across the volume of the vehicle, and use this to calculate the overall volume, as well at the center of buoyancy, which is the average position at which the buoyancy forces should be applied."|
Other topics addressed include details regarding pedestrian behaviour and (seeing that this is the PC version after all) potential for 3rd party modifications.
Link: Gamespot article