[ccp4bb] restrain range for ligand

[Danilo Belviso]

Hi! Does anybody know which is the range is used by REFMAC to vary bond 
distances, angles, and torsions of a ligand molecule during a refinement 
process? Is it possible to control and choose this range? In which way? 
Where are these information in cif dictionary obtained by sketcher in 
CCP4?
thank you!!
Danilo