We introduce PrintPut, a method for 3D printing that embeds interactivity directly into printed objects. PrintPut uses conductive filament to offer an assortment of sensors that an industrial designer can easily incorporate into their 3D designs, including buttons, pressure sensors, sliders, touchpads, and flex sensors. PrintPut combines physical and interactive sketching into the same process: seamlessly integrating sensors onto the surfaces of 3D objects, without the need for external sensor hardware.