DEM restitution coefficient
as it said in dualsphysicsv4.2guide, "the restitution coefficient ije is taken as the average of the two materials coefficients, in what is the only calibration parameter of the model." So what is the function of friction coefficient? I tried to keep restitution coefficient as constant and change friction coefficient, but the movement of the object are almost the same. Does it mean the value of friction coefficient will never influence the result?