[PyMOL] surface coloring fails with gradient loaded

[Martin Höfling]

Hi there,

i am trying to render fieldlines and sf potential together in a movie.

The movie setup is like this:

import os
set gradient_spacing=5
load ProtOut.pdb,prot
load trajshort.xtc,prot
mset 1 -7
show surface
set surface_solvent=1
for a in range(1,7): cmd.mdo(a,"delete flines;delete dxmap;delete 
dxmap2;delete rmp;delete rmp2;save 
prot.pdb,prot;os.system(\"pdb2pqr --ff=amber prot.pdb 
prot.pqr&>log.txt\");os.system(\"apbs apbs.in&>log.txt\");load 
apbsout.dx,dxmap;load apbsout.dx,dxmap2;ramp_new rmp,dxmap,
[-1.5,-0.75,0];ramp_new rmp2,dxmap,[-10,0,10];gradient 
flines,dxmap,-10,10,prot,carve=15;color rmp,flines;set 
surface_color=rmp,prot")

set ray_trace_frames=1
set cache_frames=1
mclear

Is there anything wrong on this setup?
the surface is always white. If i do a show surface in every frame, then it 
seems to me as if the surface is calculated for all frames (600 in total). 
This is too slow to do it on every step.

Any ideas?

Cheers
        Martin