The latter half of the 20th century saw the development of lightweight tensioned translucent membranes as shading devices and their increasing use in providing daylight control. The use of reliable tools for the prediction of the lighting environment experienced in daylit spaces has become essential. To date most analytic efforts related to predicting daylighting performance has concentrated on the analysis of light penetration through glass openings. Little attention has been paid to the light transmission through fabric membranes. The membranes itself are normally in tensioned creating...