Nu Boyana Film Studios have a system that can be used to spray polyurethane foam into moulds to form almost any shapes. The foam will expand up to 10/20 times when applied to the moulds. The material is resistant to fire and ultraviolet light as well as being water proof. This material can also be sculpted by hand once it has set. It has been used to form caves, trees, rocks and many more items.
The machines can also be used to apply a hard coat which does not expand as much and can be used in a mould to form almost any surface textures. It can be applied to existing surfaces to provide fire retarding and protection. The final product is strong enough that it can be walked on.