The major drawback in hot climate zones is the high intensity of solar radiation, which 
produces undesired solar heat gain and influences indoor daylighting dispet the
advantage of having enough natural lighting. Several attempts have been made to use 
Mashrabiya as an environmentally friendly architectural design element. This study 
presents a new methodology for optimizing parameters of parametric Mashrabiya 
oriented to the west in a hot arid climate in Cairo, Egypt. The study concentrates on the 
pattern parameters (Lattice) in the body part of the Mashrabiya, so it uses parametric 
design and simulation techniques to reach an optimal geometrical parameter for the 
patterns, which enhances the indoor daylighting and builds an Associative model for 
the Mashrabiya. The study also aims to investigate the influence of each parameter to 
find effective parameters on daylighting. Grasshopper for Rhino is used to generate the 
parametric variations. Ladybug and honeybee -Grasshopper plugins- for daylighting 
simulation. The methodology includes field experiments and simulation. The result of 
the study shows a significant impact of some parameters rather than others. Some cases 
achieve the required daylighting, which proves the advantage of using parametric 
Mashrabiya in façade treatment for sufficient daylighting in hot arid climates.