Visualizing Interstellar's Wormhole

Christopher Nolan's science fiction movie Interstellar offers a variety of opportunities for students in elementary courses on general relativity theory. This paper describes such opportunities, including: (i) At the motivational level, the manner in which elementary relativity concepts underlie the wormhole visualizations seen in the movie. (ii) At the briefest computational level, instructive calculations with simple but intriguing wormhole metrics, including, e.g., constructing embedding diagrams for the three-parameter wormhole that was used by our visual effects team and Christopher Nolan in scoping out possible wormhole geometries for the movie. (iii) Combining the proper reference frame of a camera with solutions of the geodesic equation, to construct a light-ray-tracing map backward in time from a camera's local sky to a wormhole's two celestial spheres. (iv) Implementing this map, for example in Mathematica, Maple or Matlab, and using that implementation to construct images of what a camera sees when near or inside a wormhole. (v) With the student's implementation, exploring how the wormhole's three parameters influence what the camera sees---which is precisely how Christopher Nolan, using our implementation, chose the parameters for \emph{Interstellar}'s wormhole. (vi) Using the student's implementation, exploring the wormhole's Einstein ring, and particularly the peculiar motions of star images near the ring; and exploring what it looks like to travel through a wormhole.Comment: 14 pages and 13 figures. In press at American Journal of Physics. Minor revisions; primarily insertion of a new, long reference 15 at the end of Section II.

Spacetime Catmull Recursive Subdivision Facilitated with Occlusion Culling

We describe an extension and a generalization of the Catmull recursive subdivision algorithm: first, an imagebased occlusion culling stage is added; second, all rendering stages, that is, view-frustum and occlusion culling, subdivision of geometric primitives into micropolygons, and rasterization, are performed in spacetime. Operating in spacetime allows to exploit temporal coherence in animated scenes

Transport-Based Neural Style Transfer for Smoke Simulations

Artistically controlling fluids has always been a challenging task. Optimization techniques rely on approximating simulation states towards target velocity or density field configurations, which are often handcrafted by artists to indirectly control smoke dynamics. Patch synthesis techniques transfer image textures or simulation features to a target flow field. However, these are either limited to adding structural patterns or augmenting coarse flows with turbulent structures, and hence cannot capture the full spectrum of different styles and semantically complex structures. In this paper, we propose the first Transport-based Neural Style Transfer (TNST) algorithm for volumetric smoke data. Our method is able to transfer features from natural images to smoke simulations, enabling general content-aware manipulations ranging from simple patterns to intricate motifs. The proposed algorithm is physically inspired, since it computes the density transport from a source input smoke to a desired target configuration. Our transport-based approach allows direct control over the divergence of the stylization velocity field by optimizing incompressible and irrotational potentials that transport smoke towards stylization. Temporal consistency is ensured by transporting and aligning subsequent stylized velocities, and 3D reconstructions are computed by seamlessly merging stylizations from different camera viewpoints.Comment: ACM Transaction on Graphics (SIGGRAPH ASIA 2019), additional materials: http://www.byungsoo.me/project/neural-flow-styl

Virtual tour

Interactive 3D Visualization of Architectural models might be the best way to get some idea about an Architecture Plan. Photo-realistic visualization often attracts the investors and customers for whom the architectural blueprints are obscure. Architectural Visualization is considered to have a bright future ahead of it as more and more architects and real estate developers are using this technology. Virtual Walk-through can give not only ideas about your building but its interiors and design too. The Architectural Virtual Environment also most widely used in Gaming and Entertainment Industry in creating a complex movie scenes or a game environment

Observing supermassive black holes in virtual reality

We present a full 360 degree (i.e., 4$\pi$ steradian) general-relativistic ray-tracing and radiative transfer calculations of accreting supermassive black holes. We perform state-of-the-art three-dimensional general relativistic magnetohydrodynamical simulations using the BHAC code, subsequently post-processing this data with the radiative transfer code RAPTOR. All relativistic and general-relativistic effects, such as Doppler boosting and gravitational redshift, as well as geometrical effects due to the local gravitational field and the observer's changing position and state of motion, are therefore calculated self-consistently. Synthetic images at four astronomically-relevant observing frequencies are generated from the perspective of an observer with a full 360-degree view inside the accretion flow, who is advected with the flow as it evolves. As an example, we calculated images based on recent best-fit models of observations of Sagittarius A*. These images are combined to generate a complete 360-degree Virtual Reality movie of the surrounding environment of the black hole and its event horizon. Our approach also enables the calculation of the local luminosity received at a given fluid element in the accretion flow, providing important applications in, e.g., radiation feedback calculations onto black hole accretion flows. In addition to scientific applications, the 360-degree Virtual Reality movies we present also represent a new medium through which to communicate black hole physics to a wider audience, serving as a powerful educational tool.Comment: 25 pages, 11 figures, 1 movie; https://www.youtube.com/watch?v=SXN4hpv977s&t=57

Ray tracing for constructive solid modeling

This thesis describes a system for the creation and realistic depiction of non-geometric, complex, three dimensional solid models by utilizing a ray tracing algorithm and a graphics relational database. Geometric primitives such as a sphere, cylinder, block, and cone are combined together by using the Boolean set operations of union (+), intersection (&), and difference (-). The three dimensional solid models are built based on the concept of constructive solid geometric modeling. The database provides functions for the creation, transformation, and deletion of the primitives and models. A model may be displayed as a wireframe for a fast display or as a shaded solid for a realistic display