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