We present a practical and inexpensive method for creating physical objects that cast different color shadow images when illuminated by prescribed lighting configurations. The input to our system is a number of lighting configurations and corresponding desired shadow images. Our approach computes attenuation masks, which are then printed on transparent materials and stacked to form a single multi-layer attenuator. When illuminated with the input lighting configurations, this multi-layer attenuator casts the prescribed color shadow images. Alternatively, our method can compute layers so that their permutations produce different prescribed shadow images under fixed lighting. Each multi-layer attenuator is quick and inexpensive to produce, can generate multiple full-color shadows, and can be designed to respond to different types of natural or synthetic lighting setups. We illustrate the effectiveness of our multi-layer attenuators in simulation and in reality, with the sun as a light source.
@article{baran12manufacturing, author = {Baran, Ilya and Keller, Philipp and Bradley, Derek and Coros, Stelian and Jarosz, Wojciech and Nowrouzezahrai, Derek and Gross, Markus}, title = {Manufacturing Layered Attenuators for Multiple Prescribed Shadow Images}, journal = {Computer Graphics Forum (Proceedings of Eurographics)}, volume = {31}, number = {2}, year = {2012}, month = may, pages = {603--610}, issn = {0167-7055}, doi = {10/gbbdcg} }