Typically, a 3D printer uses some sort of resin or other material to print physical objects that you can hold and touch. An architect from India named Ekaggrat Singh Kalsi has invented a system that combines light art with 3D printing to make a printer that creates virtual objects using light. A camera is required to capture the finished light print.
That means you can’t see the printed object as it is created like you can with a normal 3D printer. The camera is set on a long exposure so as the printer lays out the light layers they are captured on the digital camera.
Once the printer is done with its process, the final product can be seen on the camera. The finished product looks like a hologram. Kalsi is now able to print in full color thanks to a 5mm RGB LED that he attached to the micro platform of a 3DR delta with a special attachment.
He attached the LED to pins 4, 5, 6 of the Ramps board. The camera is also programmed to start and stop automatically so the shutter release doesn’t have to be held down. The final results from the printer are built as a rotating .GIF file. He also wrote a custom Grasshopper 3D script to take any 3D model and convert it into Gcode. That script controls the path of the LED and turns the light on and off.
SOURCE: 3D Printing Industry