  When walking on loose terrains, possibly covered with vegetation, the ground
and grass should deform, but the character's gait should also change
accordingly. We propose a method for modeling such two-ways interactions in
real-time. We first complement a layered character model by a high-level
controller, which uses position and angular velocity inputs to improve dynamic
oscillations when walking on various slopes. Secondly, at a refined level, the
feet are set to locally deform the ground and surrounding vegetation using
efficient procedural functions, while the character's response to such
deformations is computed through adapted inverse kinematics. While simple to
set up, our method is generic enough to adapt to any character morphology.
Moreover, its ability to generate in real time, consistent gaits on a variety
of loose grounds of arbitrary slope, possibly covered with grass, makes it an
interesting solution to enhance films and games.
