1. Create your surfaces in "CCP4" format in SURFNET.
Asides: A. The "endianness" of SURFNET is set to big endian by default - see the remarks about the SGI flag. B.SURFNET can be compiled against ccp4 version 5 and 6 libraries by following the instructions in the SURFNET distribution and modifiying the link lines at the end of ccp4link.scr to replace $CLIB/libccp4.a with $CLIB/libccp4f.a $CLIB/libccp4c.a
e.g. in a shell on LINUX:
$ lx_mapman MAPMAN > READ map1 gaps.den MAPMAN > WRITE map1 gaps.xplor XPLOR
3. Open the XPLOR map in PyMol
4. Generate a mesh or surface object from the map using isomesh or isosurface.
e.g. on the PyMol command line:
isomesh gaps_mesh, gaps, 100.0