Simple, Rasterization-based Liquids

International audienceRasterization pipelines are ubiquitous today. They can be found in most of our personal computers as well as in smaller, hand-held devices--like smart phones--with lower-end hardware. However, simulating particle-based liquids requires sorting the particles which is cumbersome when using a rasterization pipeline. In this chapter, we describe a method to simulate liquids without having to sort the particles. Our method was specifically designed for these architectures and low shader model specifications (starting from shader model 3 for 3D liquids). Instead of sorting the particles, we splat them onto a grid (i.e. a 3D or 2D texture) and solve the inter-particle dynamics directly on the grid. Splatting is simple to perform in a rasterization pipeline, but can also be costly. Thanks to the simplified pass on the grid, we only need to splat the particles once. The grid also provides additional benefits: we can easily add artificial obstacles for the particles to interact with, we can ray cast the grid directly to render the liquid surface, and we can even gain a speed up over sort-based liquid solvers--such as the optimized solver found in the DirectX 11 SDK

Thumb-bangers : exploring the cultural bond between video games and heavy metal

« Heavy Metal Generations » is the fourth volume in the series of papers drawn from the 2012 Music, Metal and Politics international conference (http://www.inter-disciplinary.net/publishing/product/heavy-metal-generations/).Heavy metal and video games share an almost simultaneous birth, with Black Sabbath’s debut album in 1970 and Nolan Bushnell’s Computer Space in 1971. From Judas Priest’s ‘Freewheel Burning’ music video in 1984 to Tim Schafer’s Brütal Legend in 2009, the exchanges between these two subcultures have been both reciprocal and exponential. This chapter will present a historical survey of the bond between video games and heavy metal cultures through its highest-profile examples. There are two underlying reasons for this symbiosis: 1) the historical development and popular dissemination of the video game came at an opportune time, first with the video game arcades in the 1970s and early 1980s, and then with the Nintendo Entertainment System, whose technical sound-channel limitations happened to fall in line with the typical structures of heavy metal; 2) heavy metal and video games, along with their creators and consumers, have faced similar sociocultural paths and challenges, notably through the policies set in place by the PMRC and the ESRB, and a flurry of lawsuits and attacks, especially from United States congressmen, that resulted in an overlapping of their respective spaces outside dominant culture. These reasons explain the natural bond between these cultural practices, and the more recent developments like Last Chance to Reason’s Level 2 let us foresee a future where new hybrid creations could emerge

Are U.S. CEOs Paid More than U.K. CEOs? Inferences from Risk- Adjusted Pay (CRI 2009-003)

We compute and compare risk-adjusted pay for US and UK CEOs, where the adjustment is based on estimated risk premiums stemming from the equity incentives borne by CEOs. Controlling for firm and industry characteristics, we find that US CEOs have higher pay, but also bear much higher stock and option incentives than UK CEOs. Using reasonable estimates of risk premiums, we find that risk-adjusted US CEO pay does not appear large compared to that of UK CEOs. We also examine differences in pay and equity incentives between a sample of non-UK European CEOs and a matched sample of US CEOs, and find that risk-adjusting pay may explain about half of the apparent higher pay for US CEOs

The Line of Action: an Intuitive Interface for Expressive Character Posing

International audienceThe line of action is a conceptual tool often used by cartoonists and illustrators to help make their figures more consistent and more dramatic. We often see the expression of characters--may it be the dynamism of a super hero, or the elegance of a fashion model--well captured and amplified by a single aesthetic line. Usually this line is laid down in early stages of the drawing and used to describe the body's principal shape. By focusing on this simple abstraction, the person drawing can quickly adjust and refine the overall pose of his or her character from a given viewpoint. In this paper, we propose a mathematical definition of the line of action (LOA), which allows us to automatically align a 3D virtual character to a user specified LOA by solving an optimization problem. We generalize this framework to other types of lines found in the drawing literature, such as secondary lines used to place arms. Finally, we show a wide range of poses and animations that were rapidly created using our system

Adding dynamics to sketch-based character animations

International audienceCartoonists and animators often use lines of action to emphasize dynamics in character poses. In this paper, we propose a physically-based model to simulate the line of action's motion, leading to rich motion from simple drawings. Our proposed method is decomposed into three steps. Based on user-provided strokes, we forward simulate 2D elastic motion. To ensure continuity across keyframes, we re-target the forward simulations to the drawn strokes. Finally, we synthesize a 3D character motion matching the dynamic line. The fact that the line can move freely like an elastic band raises new questions about its relationship to the body over time. The line may move faster and leave body parts behind, or the line may slide slowly towards other body parts for support. We conjecture that the artist seeks to maximize the filling of the line (with the character's body)---while respecting basic realism constraints such as balance. Based on these insights, we provide a method that synthesizes 3D character motion, given discontinuously constrained body parts that are specified by the user at key moments

Space-time sketching of character animation

International audienceWe present a space-time abstraction for the sketch-based design of character animation. It allows animators to draft a full coordinated motion using a single stroke called the space-time curve (STC). From the STC we compute a dynamic line of action (DLOA) that drives the motion of a 3D character through projective constraints. Our dynamic models for the line's motion are entirely geometric, require no pre-existing data, and allow full artistic control. The resulting DLOA can be refined by over-sketching strokes along the space-time curve, or by composing another DLOA on top leading to control over complex motions with few strokes. Additionally , the resulting dynamic line of action can be applied to arbitrary body parts or characters. To match a 3D character to the 2D line over time, we introduce a robust matching algorithm based on closed-form solutions, yielding a tight match while allowing squash and stretch of the character's skeleton. Our experiments show that space-time sketching has the potential of bringing animation design within the reach of beginners while saving time for skilled artists

Topographical coloured plasmonic coins

The use of metal nanostructures for colourization has attracted a great deal of interest with the recent developments in plasmonics. However, the current top-down colourization methods based on plasmonic concepts are tedious and time consuming, and thus unviable for large-scale industrial applications. Here we show a bottom-up approach where, upon picosecond laser exposure, a full colour palette independent of viewing angle can be created on noble metals. We show that colours are related to a single laser processing parameter, the total accumulated fluence, which makes this process suitable for high throughput industrial applications. Statistical image analyses of the laser irradiated surfaces reveal various distributions of nanoparticle sizes which control colour. Quantitative comparisons between experiments and large-scale finite-difference time-domain computations, demonstrate that colours are produced by selective absorption phenomena in heterogeneous nanoclusters. Plasmonic cluster resonances are thus found to play the key role in colour formation.Comment: 9 pages, 5 figure