I am very confused about Dirichlet Boundary Conditions.
Such as the example given by the manual:
bc = [mybc]
label = group A
bc_dof =  ; fixed displacement in z direction
db_initial = spatialdata.spatialdb.SimpleDB
db_initial.iohandler.filename = disp_A.spatialdb
db_initial.query_type = nearest ; change query type to nearest point algorithm
db_rate = spatialdata.spatialdb.UniformDB
db_rate.values = [displacement-rate-z]
db_rate.data = [1.0e-06 * m/s] ; velocity is 1.0e-06 m/s
From the manual, bc_dof =  (fixed displacement in z direction) means the displacement in z direction is fixed, but it laterly says group A moves at a speed of 1.0e-06 m/s in the z direction. How could this happen? Group A is fixed and moves at a speed of 1.0e-06m/s in z direction at the same time? I mean if Group A is fixed, it cannot move, right?
Hope someone can give a detailed explanation.