What is the roof on the ecopa stadium made of? and what is the specs?

Question

what is the ecopa stadium roof made of? if its possible, include the specs for the roof like mass per length

Answer 1

The Japanese engineers  made a number of independent free-form structures and placed them along the stadium. They then laid subframes between the independent structures and paced a modularized fabric roof over them. no specific specs outside the normal requirements of strength durability, weight etc.