I have a rather unusual question and I hope some of you could point me in the right direction. Some of the PCBs used in my work have the specific requirement that the solder mask has to cover the traces but only for a small distance, leaving exposed the empty board area between traces and pads. It has do do with adhesion of potting compounds. The mask looks almost like what a polygon would do with the isolate parameter, but much as I tried I couldn't get there.
BTW, I am running Eagle 6.6 Pro.