The model builder in Omega attempts to capture all of the relevant
bond length and angles, and ring conformations for an input molecule.
Fragment assembly allows for a 'divide and conquer' approach to model
building. Much of the relevant information for building a molecular
models is contained in carefully chosen fragments. makefraglib
uses distance constraints and geometry optimization to generate
fragment conformations. Only a single conformation is stored for
acyclic fragments, while all possible unique ring conformers are
retained within user defined limits. Libraries created with
makefraglib can then be provided to Omega using the
-setfraglib or -addfraglib flag.