The Friction (Rigid Body Contact) feature is used to add frictional forces and losses to the
Rigid Body Contact.
Here, Fn is the contact force,
Ff,r is the additional sliding resistance,
Ff,max is the maximum friction force,
is the slip velocity vector and
is the characteristic slip velocity.
where vc, s and
vc, d are the velocities of the source and destination spheres at the contact point. They are defined as
where vsrc and
vdst are the velocity vectors of the centers of the source and destination spheres, and the angular velocity vectors of the source and destination spheres are given by
and
. The distance vectors from the centers of the source and destination, to the contact point, are given by
rs and
rd. They are defined as
where rs and
rd are the radii of the source and destination spheres.
where Ff is the magnitude of the friction force. The friction force vector is applied also on the destination sphere, but with opposite sign.
where qsrc and
qdst are the quaternions of the source and destination spheres.
where vc,s is the velocity of the source sphere at the contact point. It is defined as
where vsrc is the velocity vector of the center of the source and
is the angular velocity vector of the source sphere. The distance vector from the center to the contact point for the source is defined as
where rs is the radius of the source sphere. The velocity of the destination boundary, at the contact point, is
vc, d.
where Ff is the magnitude of the friction force. The friction force vector applied on the destination sphere is equal, but opposite in direction.
where qsrc is the quaternion of source sphere.