SURFSUP: Learning Fluid Simulation for Novel Surfaces

Modeling the mechanics of fluid in complex scenes is vital to applications in design, graphics, and robotics. Learning-based methods provide fast and differentiable fluid simulators, however most prior work is unable to accurately model how fluids interact with genuinely novel surfaces not seen during training. We introduce SURFSUP, a framework that represents objects implicitly using signed distance functions (SDFs), rather than an explicit representation of meshes or particles. This continuous representation of geometry enables more accurate simulation of fluid-object interactions over long time periods while simultaneously making computation more efficient. Moreover, SURFSUP trained on simple shape primitives generalizes considerably out-of-distribution, even to complex real-world scenes and objects. Finally, we show we can invert our model to design simple objects to manipulate fluid flow.Comment: Website: https://surfsup.cs.columbia.edu

Multi-Scale Vector-Ridge-Detection for Perceptual Organization Without Edges

We present a novel ridge detector that finds ridges on vector fields. It is designed to automatically find the right scale of a ridge even in the presence of noise, multiple steps and narrow valleys. One of the key features of such ridge detector is that it has a zero response at discontinuities. The ridge detector can be applied to scalar and vector quantities such as color. We also present a parallel perceptual organization scheme based on such ridge detector that works without edges; in addition to perceptual groups, the scheme computes potential focus of attention points at which to direct future processing. The relation to human perception and several theoretical findings supporting the scheme are presented. We also show results of a Connection Machine implementation of the scheme for perceptual organization (without edges) using color

ProtoSpray: Combining 3D Printing and Spraying to Create Interactive Displays with Arbitrary Shapes

ProtoSpray is a fabrication method that combines 3D printing and spray coating, to create interactive displays of arbitrary shapes. Our approach makes novel use of 3D printed conductive channels to create base electrodes on 3D shapes. This is then combined with spraying active materials to produce illumination. We demonstrate the feasibility and benefits of this combined approach in 6 evaluations exploring different shaped topologies. We analyze factors such as spray orientations, surface topologies and printer resolutions, to discuss how spray nozzles can be integrated into traditional 3D printers. We present a series of ProtoSprayed objects demonstrating how our technique goes beyond existing fabrication techniques by allowing creation of displays on objects with curvatures as complex as a Mobius strip. Our work provides a platform to empower makers to use displays as a fabrication material.<br/

ProtoSpray: Combining 3D Printing and Spraying to Create Interactive Displays with Arbitrary Shapes

ProtoSpray is a fabrication method that combines 3D printing and spray coating, to create interactive displays of arbitrary shapes. Our approach makes novel use of 3D printed conductive channels to create base electrodes on 3D shapes. This is then combined with spraying active materials to produce illumination. We demonstrate the feasibility and benefits of this combined approach in 6 evaluations exploring different shaped topologies. We analyze factors such as spray orientations, surface topologies and printer resolutions, to discuss how spray nozzles can be integrated into traditional 3D printers. We present a series of ProtoSprayed objects demonstrating how our technique goes beyond existing fabrication techniques by allowing creation of displays on objects with curvatures as complex as a Mobius strip. Our work provides a platform to empower makers to use displays as a fabrication material.<br/

Path Creation with Digital 3D Representations: Networks of Innovation in Architectural Design and Construction

We examine the wake of innovations in architecture and construction propelled by the adoption of digital three dimensional (3D) representations of buildings and their parts. Departing from the traditional view of innovation that treats information technology adoption as an unproblematic, singular event, we examine IT induced innovations and their consequences as path creation created by the network of professional communities involved in architect Frank Gehry\u27s projects. We report the results of a retrospective case study of 3D representation enabled and triggered innovation during the design and construction of the Peter B. Lewis Building at Case Western Reserve University. Our analysis suggests that the consequences of a complex information technology innovation like the use of digital 3D representations of buildings and their part cannot be fully understood as a singular adoption event. Instead, a more holistic and integrated view of the innovation process as continuous path creation by multiple actors sharing practices and feedback across professional communities while they appropriate 3D representations is required. Information technology innovation is not a single event created by a heroic individual or champion, but it involves multiple agents\u27 mindful deviations from established paths of practices and resource use. We observe that the use of 3D representations breaks down the traditional loosely coupled system in construction that relied on 2D representations to share information between different contractors. These representations essentially black-boxed and hid most information how to build the building or how different parts of design interrelate with one another. To effectively adopt and appropriate the potential of 3D representations requires that traditionally isolated actors during design and construction need to be brought together in a tightly coupled system. This system is arranged around rich and complex boundary objects enabled by the digital 3D representations and their transformations

contour interpolation by vector field combination

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Manufacturing of screw rotors via 5-axis double-flank CNC machining

We investigate a recently introduced methodology for 5-axis flank computer numerically controlled (CNC) machining, called double-flank milling [1]. We show that screw rotors are well suited for this manufacturing approach where the milling tool possesses tangential contact with the material block on two sides, yielding a more efficient variant of traditional flank milling. While the tool's motion is determined as a helical motion, the shape of the tool and its orientation with respect to the helical axis are unknowns in our optimization-based approach. We demonstrate our approach on several rotor benchmark examples where the pairs of envelopes of a custom-shaped tool meet high machining accuracy.RYC-2017-22649 KAUST-BRF grant nr. 398