what is 4d printing

4D printing is an advanced form of additive manufacturing that involves creating objects with smart materials that can transform their shape and properties over time. The "fourth dimension" in 4D printing refers to the ability of the printed object to change its shape or functionality in response to external stimuli, such as temperature, light, or moisture. The process of 4D printing is similar to that used with 3D printing, which involves designing a 3D shape and then printing the object layer by layer using an additive manufacturing process. However, in 4D printing, the use of a selected smart material that can change its properties in response to external stimuli means that the finished object has added functionalities and properties not found in 3D printed objects. The resulting 3D shape is able to morph into different forms in response to environmental stimulus, with the 4th dimension being the time-dependent shape change after the printing. The materials used in 4D printing can be programmed to change shape, color, or size when they receive an external stimulus such as humidity, light, pressure, or temperature. The technology could enable the creation of self-assembling structures or materials that are able to repair themselves when damaged. 4D printing is still in the research and development phase, but some prototypes and proof-of-concept projects have already been completed.