Question: Do you think there will ever be a 4D printer? If so, what would it do that would be different to a 3D printer?

Anthony Newell answered on 4 Mar 2020:

We actually already have 4D printing but it’s a recent development! A 4D printing uses similar methods as 3D printing like resin printing. It differs in that the material that the part is printed from is programmed to change into a specific shape after printing. It reacts with something in the environment like temperature, heat or light and this causes the shape change. Engineers and scientists are already thinking of ways to use this for making custom medical implants and smart materials.