The 3D Acid Test: Perceptual Attributes vs Renderable Elements

The Romantics artificially embellished light and colour to convey emotion in their artworks. Light and colour were used to ignite a sense of enchantment and to stir an emotional response from the viewer. 3D software operates within this established visual tradition: current digital artistic representation involves a similarly embellished reality. This is a testament to what we continually want to see and how we would like to be visually entertained and informed, and physically based 3D renderer Arnold provides the tools for this continuation. Inherent in the world’s most-used 3D rendering programme Arnold are light and surface attributes which have been programmed to be adjustable to achieve myriad visual results. These attributes, however, have a history rooted in computer graphics’ plight for realism by abiding by the laws of optics and physics in their creation. However, these tools were designed with an arbitrarily chosen set of limits: arbitrary in the sense that these limits define a range of possibility to be used conveniently by the artist rather than by necessity or intrinsic nature. Johann Goethe (b. 1749), a Romantic poet, was critical of how light and colour were used by his artistic peers. He was dissatisfied by the embellishment of light and colour in paintings, and endeavoured to know exactly what was happening when he looked at things. Goethe conducted a series of experiments on light and colour, which resulted in his book Theory of Colours (1810, trans. Charles Eastlake, 1840). In my study, using Theory of Colours as a guideline, I have recreated fifty of Goethe’s experiments in 3D. I explore the fundamentals of Arnold as it was created, revealing the benchmark of current achievable 3D realism. Ten of these experiments are discussed in this paper. These experiments, in my judgment, are more applicable to the scope of phenomena replicable with a renderer, and scale the vast number of Goethe’s experiments in Theory of Colours to a reasonable set of testable conditions. The human perception of reality is the baseline against which rendering qualities must be judged, and Goethe’s experiments are replicable. As an instructor of 3D rendering, I aim to instill in my students the knowledge gained from this study, with the intention to empower the students with their own rendering so that they may make informed, predictable decisions

Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest

Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument that delivers parallaxes at about 4 microarcsec on targets as faint as V = 20, differential accuracy of 0.6 microarcsec on bright targets, and with flexible scheduling. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics. SIM PlanetQuest is currently in the detailed design phase, having completed all of the enabling technologies needed for the flight instrument in 2005. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. SIM will search for planets with masses as small as an Earth orbiting in the `habitable zone' around the nearest stars using differential astrometry, and could discover many dozen if Earth-like planets are common. It will be the most capable instrument for detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. SIM will observe significant numbers of very high- and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the galactic mass distribution and the formation and evolution of the Galactic halo. (abridged)Comment: 54 pages, 28 figures, uses emulateapj. Submitted to PAS

Drained shear strength characteriestics of an argillaceous residuum from weathered mudstone

M.S.Paul W. Mayn