You don't need to do it one by one. You can do it at once by following the command sequence I will tell you: Slabs / select all / Slab calculation axis edit / Flat reinforcement at the bottom on the top (mark) / ok / right click cancel When you do this, all tiles will be changed at once. As far as I know, there is no way to set it from the beginning. good work.... N. YILMAZ