Car Physics for Games (2003)
a year ago
- #vehicle simulation
- #car physics
- #game development
- Introduction to car physics modeling for games, focusing on vehicle physics simulation.
- Key simplification involves handling longitudinal (forward/backward) and lateral (sideways) forces separately.
- Longitudinal forces include wheel force, braking force, rolling resistance, and drag (air resistance).
- Lateral forces allow the car to turn and are caused by sideways friction on the wheels.
- Assumption: rear wheels provide all the drive (adaptations needed for four-wheel drives).
- Use of S.I. units (meters, kilograms, Newtons) with a conversion table for imperial measures provided.
- Traction force is calculated using engine force and a unit vector in the car's heading direction.
- Air resistance (drag) is proportional to the square of velocity, becoming significant at high speeds.
- Rolling resistance is proportional to velocity and is the main resistance force at low speeds.
- Total longitudinal force is the sum of traction, drag, and rolling resistance forces.
- Car acceleration is determined by net force and mass via Newton's second law (a = F/M).
- Velocity and position are updated using numerical integration (Euler method).
- Top speed is determined by equilibrium between traction and resistance forces, not set manually.
- Weight transfer affects traction force per wheel, important for visual realism and handling.
- Engine torque depends on RPM, converted to drive force via gear ratios, differential, and efficiency.
- Slip ratio defines the relationship between wheel rotation and car movement, affecting traction.
- High-speed cornering involves slip angles and lateral forces, modeled using cornering stiffness.
- Pacejka Magic Formula mentioned for more accurate tire behavior modeling.
- Demo and source code available for practical implementation of high-speed cornering.