For last 20 years, sort of by accident, I’ve been bragging to co-design Złote Tarasy roof in Warsaw, Poland. Sometimes, being falsly humble, I add that such expensive roof is barely visible – „what a waste of money”. Occasionaly I share the drawings or show peculiar places. But only after recently I realized the hidden complexity of Złote roof geometry.

When you deal with simple shapes like a circle or square then the ofsetting in or outwards is same as scaling with negative or positive number according to the center. In 3D the issue is more complex – the offset of external surface to obtain the centerline of structural member supporting e.g. glazing is not so simple.