  Research into the processes of photoionised nebulae plays a significant part
in our understanding of stellar evolution. It is extremely difficult to
visually represent or model ionised nebula, requiring astronomers to employ
sophisticated modelling code to derive temperature, density and chemical
composition. Existing codes are available that often require steep learning
curves and produce models derived from mathematical functions. In this article
we will introduce PyCross: PyCloudy Rendering Of Shape Software. This is a
pseudo 3D modelling application that generates photoionisation models of
optically thin nebulae, created using the Shape software. Currently PyCross has
been used for novae and planetary nebulae, and it can be extended to Active
Galactic Nuclei or any other type of photoionised axisymmetric nebulae.
Functionality, an operational overview, and a scientific pipeline will be
described with scenarios where PyCross has been adopted for novae (V5668
Sagittarii (2015) & V4362 Sagittarii (1994)) and a planetary nebula (LoTr1).
Unlike the aforementioned photoionised codes this application does not require
any coding experience, nor the need to derive complex mathematical models,
instead utilising the select features from Cloudy/PyCloudy and Shape. The
software was developed using a formal software development lifecycle, written
in Python and will work without the need to install any development
environments or additional python packages. This application, Shape models and
PyCross archive examples are freely available to students, academics and
research community on GitHub for download
(https://github.com/karolfitzgerald/PyCross_OSX_App).
