  We present a pipeline for printing interactive and always-on magnetophoretic
displays using affordable Fused Deposition Modeling (FDM) 3D printers. Using
our pipeline, an end-user can convert the surface of a 3D shape into a matrix
of voxels. The generated model can be sent to an FDM 3D printer equipped with
an additional syringe-based injector. During the printing process, an oil and
iron powder-based liquid mixture is injected into each voxel cell, allowing the
appearance of the once-printed object to be editable with external magnetic
sources. To achieve this, we made modifications to the 3D printer hardware and
the firmware. We also developed a 3D editor to prepare printable models. We
demonstrate our pipeline with a variety of examples, including a printed
Stanford bunny with customizable appearances, a small espresso mug that can be
used as a post-it note surface, a board game figurine with a computationally
updated display, and a collection of flexible wearable accessories with
editable visuals.
