Austrian eyewear manufacturer Rolf has designed a collection of glasses that are 3D printed from a mixture of water and powdered castor beans. The Tyrol-based brand's latest plant-based glasses collection, called Substance, is made from beans taken from castor trees. The range has been shortlisted in the product design category of Dezeen Awards 2020. As the peel of the bean is toxic, it removes this before grinding down the remaining contents into a powder. This is then 3D printed into frames for glasses, using mainly water as the binding material. According to Rolf, the tall, fast-growing plants are grown in tropical climates without any genetic engineering, and they don't compete with food crops.