Add arrows

import molsysmt as msm
from molsysmt import pyunitwizard as puw
import numpy as np

molecular_system = msm.convert('181L', selection='molecule_type=="protein"')

view = msm.view(molecular_system)

msm.thirds.nglview.add_arrows(view, origin=puw.quantity([[0,0,0],[0,0,0],[0,0,0]], 'angstroms'),
                              vectors=puw.quantity([[10,0,0],[0,10,0],[0,0,10]], 'angstroms'),
                              color=['#FF0000', '#00FF00', '#0000FF'], radius='0.2 angstroms')

view

view = msm.view(molecular_system)

msm.thirds.nglview.add_arrows(view, origin='atom_name=="CA"', vectors='[2,2,2] angstroms')

view

view = msm.view(molecular_system)

msm.thirds.nglview.add_arrows(view, origin='atom_name=="CA" and group_index==10',
                                    end='atom_name=="CA" and group_index==110', color='#b100cd', radius='0.5 angstroms')

view