Polytopes and Coxeter Groups My first encounter with four-dimensional polytopes was Jenn 3D (2001-2007) by Fritz Obermeyer. Jenn describes itself as follows: Jenn is a toy for playing with various quotients of Cayley graphs of finite Coxeter groups on four generators. Jenn builds the graphs using the Todd-Coxeter algorithm, embeds them into the 3-sphere, and stereographically projects them onto Euclidean 3-space. Wow. We will also go one step further, and discuss how these structures can be ray traced in realtime. Symmetries of the cube We will start out in three dimensions with a familiar object: the cube. The cube has several automorphisms - transformations that will map the cube onto itself. Including the identity transformation, and taking into account that we could also mirror each one of these transformations, we arrive at 48 automorphisms for the cube. Besides the rotation symmetries above, we can also depict the reflection symmetries. This means we can establish the following relations between the generators:
Fragmentarium In some ways path tracing is one of the simplest and most intuitive ways to do ray tracing. Imagine you want to simulate how the photons from one or more light sources bounce around a scene before reaching a camera. Each time a photon hits a surface, we choose a new randomly reflected direction and continue, adjusting the intensity according to how likely the chosen reflection is. Though this approach works, only a very tiny fraction of paths would terminate at the camera. So instead, we might start from the camera and trace the ray from here and until we hit a light source. And, if the light source is large and slowly varying (for instance when using Image Based Lighting), this may provide good results. But if the light source is small, e.g. like the sun, we have the same problem: the chance that we hit a light source using a path of random reflections is very low, and our image will be very noisy and slowly converging. Diffuse reflections How to solve the rendering equation and Sky model
examples:reaction-diffusion [Morpheus] 1D reaction-diffusion: Activator-Inhibitor Space-time plot of 1D reaction diffusion model. Introduction Model description This 1D PDE model uses a Lattice with linear structure and periodic boundary conditions. The PDE defined two species called Layers: A (activator) and I (inhibitor) with resp. low and high Diffusion rates. The results are recorded and visualized using the Logger and SpaceTimeLogger. Model ActivatorInhibitor_1D.xml <MorpheusModel version="1"><Description><Title>Example-ActivatorInhibitor1D</Title></Description><Space><Lattice class="linear"><Size value="100 0 0"/><BoundaryConditions><Condition boundary="x" type="periodic"/></BoundaryConditions><NodeLength unit="micron" value="0.25"/></Lattice></Space><Time><StartTime value="0"/><StopTime value="2000"/><SaveInterval value="0"/><! In Morpheus GUI: Examples → PDE → ActivatorInhibitor_1D.xml 2D reaction-diffusion: Activator-Inhibitor Stripe pattern generated by 2D Gierer-Meinhardt model Description ActivatorInhibitor_2D.xml
Distance Estimated 3D Fractals (III): Folding Space The previous posts (part I, part II) introduced the basics of rendering DE (Distance Estimated) systems, but left out one important question: how do we create the distance estimator function? Drawing spheres Remember that a distance estimator is nothing more than a function, that for all points in space returns a length smaller than (or equal to) the distance to the closest object. It is fairly easy to come up with distance estimators for most simple geometric shapes. (1) DE(p) = max(0.0, length(p)-R) // solid sphere, zero interior (2) DE(p) = length(p)-R // solid sphere, negative interior (3) DE(p) = abs(length(p)-R) // hollow sphere shell From the outside all of these look similar. What about the first two? From left to right: Sphere (1), with normal artifacts because the normal was not backstepped. Notice that distance estimation only tells the distance from a point to an object. Combining objects Distance fields have some nice properties. So now we have a way to combine objects.
Fixed Gear Calculator - Ratio & Skid Patch for all! Le "Fantastic Fixed Gear Calculator" vous est gentillement offert par l'quide de SURPLACE, ouai ouai on est sympa. Toutes les donnes relatives aux circonfrences de pneu proviennent du fantastique site de Sheldon Brown. Merci lajalousie pour les corrections apportes au calcul des skid patchs ambidextres A cause du manque de support (correct) des canvas et d'html5, a ne marchera probablement pas (ou mal) dans Internet Explorer, mais a intresse qui? Alors profitez !
studioluminaire.com Generative Art Links Some links to Generative Art, Math & Fractals, and other creative ways of creating computional imagery. The list is not meant to be exhaustive: rather, it is a list of my favorite links. Generative Art Software General-Purpose Software Processing is probably the most used platform for Generative Art. Nodebox – A Python based alternative to Processing. vvvv is “a toolkit for real time video synthesis”. PureData a “real-time graphical dataflow programming environment for audio, video, and graphical processing.” Specific Systems Context Free Art – uses Context Free Design Grammars to generate 2D images. Structure Synth – my own attempt to extend Context Free Art into three dimensions. TopMod3D – “is a free, open source, portable, platform independent topological mesh modeling system that allows users to create high genus 2-manifold meshes”. Ready. K3DSurf – 3D surface generator (for a nice example check out this one by Schmiegl). Fractals and Math Art Software Fragmentarium. GLSL Sandbox by Mr.
Architecture pour la Liturgie – Aménagement des espaces sacrés au service de la Liturgie catholique Reaction Diffusion in 3-Dimensions Articles —> Reaction Diffusion in 3-Dimensions inShare The Gray-Scott model is a mathematical model which describes behavior two chemicals based upon their diffusion, addition and removal rates, and reaction together. In an earlier article I described the details of the Gray-Scott Reaction Diffusion model. The Model in 3-Dimensions In two dimensions a reaction diffusion model is represented by a 2-dimensional grid, visualization of which is via an image in which each grid value is represented by a pixel in the corresponding image. The mathematical model itself does not vastly change, but some aspects did require modification. Visualization Visualization of the model is much more difficult in three dimensions. To nicely render each triangle using OpenGL shading the surface normals needed to be calculated. Left: No normal averaging. Finally, the process was set in motion. 3D OpenGL Reaction Diffusion User Interface (Java) Difficulties Results Videos Reaction Diffusion in 3D. Back to Articles
Bonus: Luma Pictures’ new tools for Doctor Strange Doctor Strange has been a huge film for Marvel. To achieve their sections of the film, Luma Pictures developed a set of new tools, including some they will even be sharing with the community. Luma Pictures worked on several key sequences including the opening London sequence and they also booked ended the film with the Dormammu sequence and the Dark realm. London For the London sequence Luma developed a new fractal tool to do volumetric meshing and transforming of the buildings. "With what we needed to do we needed to art direct the speed, the movement and look at all of these 'fractals'," says Cirelli. Luma pictures literally choreographed the fractals, "which is not an easy task." The Mandelboxes are different from Mandleblubs used the film Suicide Squad. "The Mandelbox that we used allowed us to do all the arranging, mirroring and manipulation of the frequency of the volume of the London buildings, along with all the slicing and dicing," explained Cirelli. Vince Cirelli VFX Supervisor
121GASSELI Hunting style wax jacket - All the collection - Maje.com Your cookies When you use our website, personal data may be collected depending on the cookie settings you select. Where you accept cookies, they will improve your experience on our site for as long as they are in use. Below is a detailed description of the cookies that can be stored on MAJE website, data controller. You can decide whether to allow each category of cookies to be stored on your device. To learn more about cookie management on our site, see our cookie management policy Cookies that are strictly necessary Technical cookies allow you to use the site and access the different products and services we offer. dwsid / uuid, cookieLab, qb_generic, qb_permanent, qb_session, qb_t003-product-id-*, stc*, wl_anonymous, headerbannerdisplay Cookies for performance and personalisation Performance and personalisation cookies are functional cookies. Cookies for advertising or personalised advertising
Turn hyper kids into power generators with this energy-storing jump rope If you have kids, there’s inevitably been a few moments in your life where you’ve found yourself exhausted, slumped over, and completely defeated as your hyperactive children run laps around you. Kids just seem to have endless amounts of energy. Well what if you could harness some of that energy and use it for something else? If humanity could somehow tap into the kinetic power reserves of all the rambunctious kids on the planet, the world’s energy problems might be solved overnight. Uncharted Play, the company behind the revolutionary power-generating SOCCKET soccer ball, has devised yet another brilliant way to make kid-power a legitimate source of renewable energy – and it’s much more humane than chaining junior inside a giant hamster wheel. PULSE is a high-tech jump rope that harnesses kinetic energy from your children’s motion, and converts it into usable electricity. These first 100 PULSE jump ropes are available from Uncharted Play for $129 apiece. Find out more here.