PossibleImpossibles: Exploratory Procedural Design of Impossible Structures

Abstract

We present a method for generating structures in three-dimensional space that appear to be impossible when viewed from specific perspectives. Previous approaches focus on helping users to edit specific structures and require users to have knowledge of structural positioning causing the impossibility. On the contrary, our system is designed to aid users without prior knowledge to explore a wide range of potentially impossible structures. The essence of our method lies in features we call visual bridges that confuse viewers regarding the depth of the resulting structure. We use these features as starting points and employ procedural modeling to systematically generate the result. We propose scoring functions for enforcing desirable spatial arrangement of the result and use Sequential Monte Carlo to sample outputs that score well under these functions. We also present a proof-ofconcept user interface and demonstrate various results generated using our system.