I want to construct a spherical cluster which contains many molecules. So I have to pack the molecules into spherical region.I find a post recommend to pack molecules into spherical isosurface.After the isosurface is created by the script attached to the post,I try to pack molecules into it,but no molecule is in the spherical region, instead, all molecules are packed outside this region.Here are the script and structure.How can I pack the molecules into spherical region created by the script?Or how to make a spherical cluster by MS? My version is 7.0.

Thanks a lot

Sincerely 
Li



#!perl

use strict;
use MaterialsScript qw(:all);

my \$boxSize = 40; # size of the box in angstrom
my \$resolution = 2; # resolution of the field in angstrom

# create an empty box
my \$doc = Documents->New("droplet.xsd");
Tools->CrystalBuilder->SetSpaceGroup("P1");
Tools->CrystalBuilder->SetCellParameters(\$boxSize, \$boxSize, \$boxSize, 90.0, 90.0, 90.0);
Tools->CrystalBuilder->Build(\$doc);

# add a field
my \$field = \$doc->CreateField(\$resolution);

# set the field value to the (fractional) distance from the box centre
my \$probe = \$field->CreateFieldProbe([ProbeMode => "NearestGridPoint"]);
my \$extent1 = \$field->GridExtent1;
my \$extent2 = \$field->GridExtent2;
my \$extent3 = \$field->GridExtent3;
for (my \$i = 0; \$i < \$extent1; \$i++)
{
    for (my \$j = 0; \$j < \$extent2; \$j++)
    {
        for (my \$k = 0; \$k < \$extent3; \$k++)
        {
            \$probe->ProbeVoxelPosition = Point(X => \$i, Y => \$j, Z => \$k);
            my \$frac = \$probe->ProbeFractionalPosition;
            my \$rx = \$frac->X-0.5;
            my \$ry = \$frac->Y-0.5;
            my \$rz = \$frac->Z-0.5;
            my \$distance = sqrt(\$rx**2+\$ry**2+\$rz**2);
            \$probe->FieldValue = \$distance;
        }
    }
}
\$probe->Delete;

# add an isosurface
\$field->CreateIsosurface([Isovalue => 0.35]);
\$field->IsVisible = "No";