So how do you initiate a creep study?   SWX online help (2014) shows that there is a "creep" model in non-linear, but I can't see it in ANY materials.   There IS a checkbox in most (if not all) materials that says "creep effects", but it's always grey'd out (won't allow me to select it).

My assmuption is that there needs to be some specific material properties defined to be able to select "creep effects", but based on the description of the creep model, I can't quite figure out what I need in order to start a simulation.   Much thanks to anybody who can shed light on this.