Building predictive models for iterative drug design in the absence of
a known target protein structure is an important challenge. We presen
t a novel technique, Compass, that removes a major obstacle to accurat
e prediction by automatically selecting conformations and alignments o
f molecules without the benefit of a characterized active site. The te
chnique combines explicit representation of molecular shape with neura
l network learning methods to produce highly predictive models, even a
cross chemically distinct classes of molecules. We apply the method to
predicting human perception of musk odor and show how the resulting m
odels can provide graphical guidance for chemical modifications.