Abstract: We describe DynaFusion, a modeling system for interactive impossible objects. Impossible objects are defined as multiple 3D polygonal meshes with edge visibility information and a set of constraints that define pointwise relationships between the meshes. A user can easily create such models with our modeling tool. The back-end of our system is a constraint solver that seamlessly combines multiple meshes in a projected 2D domain with 3D line orientations and that maintains coherence for each successive viewpoint, thereby allowing the user to rotate the impossible object without losing visual continuity of the edges. We believe that our system will stimulate the creation of innovative artworks.