An image display system and method that use physical models to produce a
realistic display of a scene are disclosed. The image display method
involves operating a computer having a display screen, a memory and a
processing unit for simulating the motion of objects and displaying the
results on the display screen. The method includes the steps of storing
in the memory position and velocity parameters which define an initial
state of a model system having a plurality of bodies, storing in the
memory parameters which define at least one constraint function
constraining the motion of the bodies in the model system, and
calculating in the processor the position and velocity parameters which
define the state of the system after a predetermined time step based on
rigid body dynamics, including carrying out a semi-implicit integration
step subject to the constraints, to determine the velocity after the
step, including determining the constraint forces that act to keep the
system in compliance with the constraints by ensuring that the first
derivative of the constraint function is zero.