Thanks benelot, here are some answers to your questions:
- I am interested if a game like this needs a lot of physics tweaking to get realistic effects?
Yes, I suppose you could say that. Bullet is used for all rigid body dynamics and collision detection. The water is simulated by our custom engine, the results of which are applied as forces/torques to the bullet rigid bodies.
- Could you deploy the game on all devices with bullet physics?
Yes, the same code is used across all devices, everything from iPhone 4S to PS4.
- Did you use basic physics engine components or did you have to build additional components of higher complexity?
- Of course you surely built physics models of the drivers and boats, but I mean if you had to build other components?
The biggest custom module is our water simulation. We also built a custom ragdoll authoring tool which lets our artists visually build ragdolls using bullet shapes and constraints. And yes, the handling of the vehicles is also very custom.
- Also, does it require a lot of mechanical physics animations instead of using simulated physics?
- Do you control the physics objects by forces and torques or do you control kinematic objects and then integrate its motion into the physics world?
Most of the set pieces in the levels are running animations authored by the artists in Maya. For interactive objects, physics is used as much as possible. The handling of the vehicles is all done with forces and torques, but there is a lot of custom calculation taking place to get the 'feel' just right. The riders are animated with a combination of regular and additive animations. Some of these animations are triggered as a result of physics forces/impacts on the vehicle.