shear displacement

Submitted by yangdm on Tue, 06/19/2012 - 16:12

Can anyone help me understand the rotation of shear displacement in LIGGGHTS? The update of shear[0] += vtr1*dt is fine, but I am bit confused with shear[0] -= rsht*deltx. Why has it to rotate and why it is a minus?
Many thanks.

(Problem solved)