  This paper demonstrates a methodology to help practitioners maximise the
utility of complex multidisciplinary engineering models implemented as
spreadsheets, an area presenting unique challenges. As motivation we
investigate the expanding use of Integrated Resource Management(IRM) models
which assess the sustainability of urban masterplan designs. IRM models reflect
the inherent complexity of multidisciplinary sustainability analysis by
integrating models from many disciplines. This complexity makes their use
time-consuming and reduces their adoption.
  We present a methodology and toolkit for analysing multidisciplinary
engineering models implemented as spreadsheets to alleviate such problems and
increase their adoption. For a given output a relevant slice of the model is
extracted, visualised and analysed by computing model and interdisciplinary
metrics. A sensitivity analysis of the extracted model supports engineers in
their optimisation efforts. These methods expose, manage and reduce model
complexity and risk whilst giving practitioners insight into multidisciplinary
model composition. We report application of the methodology to several
generations of an industrial IRM model and detail the insight generated,
particularly considering model evolution.
