[Chimera-users] Questions about the electric fieldline

Hi I want to make the electric fieldline but there are always some problems. I did this as follows, 1. run add charge to the system 2. run APBS, the I get the electrostatic surface and a file named 1.dx 3. open 1.dx 4.measure fieldLines #0 lines 500 startAbove 10 color pink linewidth 2 then I get the problem : no volume specified I have check the userguide of measure fieldlines, but there is nothing about the volume. measure fieldLines map-model(s) [ lines N ] [ startAbove cutoff ] [ step s ] [ modelId model-number ] [ color line-color ] [ lineWidth width ] [ tubeRadius radius ] [ circleSubdivisions M ] [ markers true|false ] what should I do next? Thanks. Qiao Xue xmgign@126.com