Dear all,
I can't add an external force to a .xsd file by using such a script in material studio 2017R2, just as below:

#!perl

use strict;
use Getopt::Long;
use MaterialsScript qw(:all);

my \$doc = \$Documents{"SWNT.xsd"};
my \$forcite = Modules->Forcite;
my \$dynamics = \$forcite->Dynamics;





Modules->Forcite->ChangeSettings([Ensemble3D => "NVT",
NumberOfSteps => 50000,
CurrentForcefield => "Dreiding",
WriteForces=> "Yes",
Quality => "Coarse",

TimeStep => 1, # fs
TrajectoryFrequency => 20,
ExternalForceSet => "Right",
ExternalForceStrength => 10000,
ExternalForceX=>0,
ExternalForceY=>0,
ExternalForceZ=>-1,
CounterExternalForce =>"No",


]);


Modules->Forcite->Dynamics->Run(\$doc); (------line 32)


an error happened when script carried out

"Could not calculate the forces.
External Force set not present in Forcite.Dynamics (function/property "Run") at -e line 32."

would you help me solve this problem.

yours

CF